Merge pull request #1004 from nelsonag/cpp_math

Convert math.f90 to C++
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Paul Romano 2018-05-19 15:24:29 -05:00 committed by GitHub
commit 04441ca619
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15 changed files with 1463 additions and 871 deletions

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@ -435,6 +435,7 @@ set(LIBOPENMC_CXX_SRC
src/initialize.cpp
src/finalize.cpp
src/hdf5_interface.cpp
src/math_functions.cpp
src/message_passing.cpp
src/plot.cpp
src/random_lcg.cpp

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@ -47,3 +47,4 @@ from .mesh import *
from .filter import *
from .tally import *
from .settings import settings
from .math import *

250
openmc/capi/math.py Normal file
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@ -0,0 +1,250 @@
from ctypes import (c_int, c_double, POINTER)
import numpy as np
from numpy.ctypeslib import ndpointer
from . import _dll
_dll.t_percentile_c.restype = c_double
_dll.t_percentile_c.argtypes = [c_double, c_int]
_dll.calc_pn_c.restype = None
_dll.calc_pn_c.argtypes = [c_int, c_double, ndpointer(c_double)]
_dll.evaluate_legendre_c.restype = c_double
_dll.evaluate_legendre_c.argtypes = [c_int, POINTER(c_double), c_double]
_dll.calc_rn_c.restype = None
_dll.calc_rn_c.argtypes = [c_int, ndpointer(c_double), ndpointer(c_double)]
_dll.calc_zn_c.restype = None
_dll.calc_zn_c.argtypes = [c_int, c_double, c_double, ndpointer(c_double)]
_dll.rotate_angle_c.restype = None
_dll.rotate_angle_c.argtypes = [ndpointer(c_double), c_double,
POINTER(c_double)]
_dll.maxwell_spectrum_c.restype = c_double
_dll.maxwell_spectrum_c.argtypes = [c_double]
_dll.watt_spectrum_c.restype = c_double
_dll.watt_spectrum_c.argtypes = [c_double, c_double]
_dll.broaden_wmp_polynomials_c.restype = None
_dll.broaden_wmp_polynomials_c.argtypes = [c_double, c_double, c_int,
ndpointer(c_double)]
def t_percentile(p, df):
""" Calculate the percentile of the Student's t distribution with a
specified probability level and number of degrees of freedom
Parameters
----------
p : float
Probability level
df : int
Degrees of freedom
Returns
-------
float
Corresponding t-value
"""
return _dll.t_percentile_c(p, df)
def calc_pn(n, x):
""" Calculate the n-th order Legendre polynomial at the value of x.
Parameters
----------
n : int
Legendre order
x : float
Independent variable to evaluate the Legendre at
Returns
-------
float
Corresponding Legendre polynomial result
"""
pnx = np.empty(n + 1, dtype=np.float64)
_dll.calc_pn_c(n, x, pnx)
return pnx
def evaluate_legendre(data, x):
""" Finds the value of f(x) given a set of Legendre coefficients
and the value of x.
Parameters
----------
data : iterable of float
Legendre coefficients
x : float
Independent variable to evaluate the Legendre at
Returns
-------
float
Corresponding Legendre expansion result
"""
data_arr = np.array(data, dtype=np.float64)
return _dll.evaluate_legendre_c(len(data),
data_arr.ctypes.data_as(POINTER(c_double)),
x)
def calc_rn(n, uvw):
""" Calculate the n-th order real Spherical Harmonics for a given angle;
all Rn,m values are provided for all n (where -n <= m <= n).
Parameters
----------
n : int
Harmonics order
uvw : iterable of float
Independent variable to evaluate the Legendre at
Returns
-------
numpy.ndarray
Corresponding real harmonics value
"""
num_nm = (n + 1) * (n + 1)
rn = np.empty(num_nm, dtype=np.float64)
uvw_arr = np.array(uvw, dtype=np.float64)
_dll.calc_rn_c(n, uvw_arr, rn)
return rn
def calc_zn(n, rho, phi):
""" Calculate the n-th order modified Zernike polynomial moment for a
given angle (rho, theta) location in the unit disk. The normalization of
the polynomials is such that the integral of Z_pq*Z_pq over the unit disk
is exactly pi
Parameters
----------
n : int
Maximum order
rho : float
Radial location in the unit disk
phi : float
Theta (radians) location in the unit disk
Returns
-------
numpy.ndarray
Corresponding resulting list of coefficients
"""
num_bins = ((n + 1) * (n + 2)) // 2
zn = np.zeros(num_bins, dtype=np.float64)
_dll.calc_zn_c(n, rho, phi, zn)
return zn
def rotate_angle(uvw0, mu, phi=None):
""" Rotates direction cosines through a polar angle whose cosine is
mu and through an azimuthal angle sampled uniformly.
Parameters
----------
uvw0 : iterable of float
Original direction cosine
mu : float
Polar angle cosine to rotate
phi : float, optional
Azimuthal angle; if None, one will be sampled uniformly
Returns
-------
numpy.ndarray
Rotated direction cosine
"""
uvw0_arr = np.array(uvw0, dtype=np.float64)
if phi is None:
_dll.rotate_angle_c(uvw0_arr, mu, None)
else:
_dll.rotate_angle_c(uvw0_arr, mu, c_double(phi))
uvw = uvw0_arr
return uvw
def maxwell_spectrum(T):
""" Samples an energy from the Maxwell fission distribution based
on a direct sampling scheme.
Parameters
----------
T : float
Spectrum parameter
Returns
-------
float
Sampled outgoing energy
"""
return _dll.maxwell_spectrum_c(T)
def watt_spectrum(a, b):
""" Samples an energy from the Watt energy-dependent fission spectrum.
Parameters
----------
a : float
Spectrum parameter a
b : float
Spectrum parameter b
Returns
-------
float
Sampled outgoing energy
"""
return _dll.watt_spectrum_c(a, b)
def broaden_wmp_polynomials(E, dopp, n):
""" Doppler broadens the windowed multipole curvefit. The curvefit is a
polynomial of the form a/E + b/sqrt(E) + c + d sqrt(E) ...
Parameters
----------
E : float
Energy to evaluate at
dopp : float
sqrt(atomic weight ratio / kT), with kT given in eV
n : int
Number of components to the polynomial
Returns
-------
numpy.ndarray
Resultant leading coefficients
"""
factors = np.zeros(n, dtype=np.float64)
_dll.broaden_wmp_polynomials_c(E, dopp, n, factors)
return factors

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@ -10,6 +10,7 @@ module openmc_api
use geometry_header
use hdf5_interface
use material_header
use math
use mesh_header
use message_passing
use nuclide_header

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@ -119,7 +119,7 @@ contains
else
! Sample azimuthal angle
phi = this % phi % sample()
uvw(:) = rotate_angle(this % reference_uvw, mu, phi)
uvw = rotate_angle(this % reference_uvw, mu, phi)
end if
end function polar_azimuthal_sample

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@ -1,5 +1,5 @@
/* Copyright (c) 2012 Massachusetts Institute of Technology
*
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
@ -7,17 +7,17 @@
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* Available at: http://ab-initio.mit.edu/Faddeeva

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@ -6,6 +6,18 @@ module math
use random_lcg, only: prn
implicit none
private
public :: t_percentile
public :: calc_pn
public :: calc_rn
public :: calc_zn
public :: evaluate_legendre
public :: rotate_angle
public :: maxwell_spectrum
public :: watt_spectrum
public :: faddeeva
public :: w_derivative
public :: broaden_wmp_polynomials
!===============================================================================
! FADDEEVA_W evaluates the scaled complementary error function. This
@ -13,6 +25,86 @@ module math
!===============================================================================
interface
pure function t_percentile(p, df) bind(C, name='t_percentile_c') &
result(t)
use ISO_C_BINDING
implicit none
real(C_DOUBLE), value, intent(in) :: p
integer(C_INT), value, intent(in) :: df
real(C_DOUBLE) :: t
end function t_percentile
pure subroutine calc_pn(n, x, pnx) bind(C, name='calc_pn_c')
use ISO_C_BINDING
implicit none
integer(C_INT), value, intent(in) :: n
real(C_DOUBLE), value, intent(in) :: x
real(C_DOUBLE), intent(out) :: pnx(n + 1)
end subroutine calc_pn
pure function evaluate_legendre_c_intfc(n, data, x) &
bind(C, name='evaluate_legendre_c') result(val)
use ISO_C_BINDING
implicit none
integer(C_INT), value, intent(in) :: n
real(C_DOUBLE), intent(in) :: data(n)
real(C_DOUBLE), value, intent(in) :: x
real(C_DOUBLE) :: val
end function evaluate_legendre_c_intfc
pure subroutine calc_rn(n, uvw, rn) bind(C, name='calc_rn_c')
use ISO_C_BINDING
implicit none
integer(C_INT), value, intent(in) :: n
real(C_DOUBLE), intent(in) :: uvw(3)
real(C_DOUBLE), intent(out) :: rn(2 * n + 1)
end subroutine calc_rn
pure subroutine calc_zn(n, rho, phi, zn) bind(C, name='calc_zn_c')
use ISO_C_BINDING
implicit none
integer(C_INT), value, intent(in) :: n
real(C_DOUBLE), value, intent(in) :: rho
real(C_DOUBLE), value, intent(in) :: phi
real(C_DOUBLE), intent(out) :: zn(((n + 1) * (n + 2)) / 2)
end subroutine calc_zn
subroutine rotate_angle_c_intfc(uvw, mu, phi) bind(C, name='rotate_angle_c')
use ISO_C_BINDING
implicit none
real(C_DOUBLE), intent(inout) :: uvw(3)
real(C_DOUBLE), value, intent(in) :: mu
real(C_DOUBLE), optional, intent(in) :: phi
end subroutine rotate_angle_c_intfc
function maxwell_spectrum(T) bind(C, name='maxwell_spectrum_c') &
result(E_out)
use ISO_C_BINDING
implicit none
real(C_DOUBLE), value, intent(in) :: T
real(C_DOUBLE) :: E_out
end function maxwell_spectrum
function watt_spectrum(a, b) bind(C, name='watt_spectrum_c') &
result(E_out)
use ISO_C_BINDING
implicit none
real(C_DOUBLE), value, intent(in) :: a
real(C_DOUBLE), value, intent(in) :: b
real(C_DOUBLE) :: E_out
end function watt_spectrum
subroutine broaden_wmp_polynomials(E, dopp, n, factors) &
bind(C, name='broaden_wmp_polynomials_c')
use ISO_C_BINDING
implicit none
real(C_DOUBLE), value, intent(in) :: E
real(C_DOUBLE), value, intent(in) :: dopp
integer(C_INT), value, intent(in) :: n
real(C_DOUBLE), intent(inout) :: factors(n)
end subroutine broaden_wmp_polynomials
function faddeeva_w(z, relerr) bind(C, name='Faddeeva_w') result(w)
use ISO_C_BINDING
implicit none
@ -24,696 +116,17 @@ module math
contains
!===============================================================================
! NORMAL_PERCENTILE calculates the percentile of the standard normal
! distribution with a specified probability level
!===============================================================================
elemental function normal_percentile(p) result(z)
real(8), intent(in) :: p ! probability level
real(8) :: z ! corresponding z-value
real(8) :: q
real(8) :: r
real(8), parameter :: p_low = 0.02425_8
real(8), parameter :: a(6) = (/ &
-3.969683028665376e1_8, 2.209460984245205e2_8, -2.759285104469687e2_8, &
1.383577518672690e2_8, -3.066479806614716e1_8, 2.506628277459239e0_8 /)
real(8), parameter :: b(5) = (/ &
-5.447609879822406e1_8, 1.615858368580409e2_8, -1.556989798598866e2_8, &
6.680131188771972e1_8, -1.328068155288572e1_8 /)
real(8), parameter :: c(6) = (/ &
-7.784894002430293e-3_8, -3.223964580411365e-1_8, -2.400758277161838_8, &
-2.549732539343734_8, 4.374664141464968_8, 2.938163982698783_8 /)
real(8), parameter :: d(4) = (/ &
7.784695709041462e-3_8, 3.224671290700398e-1_8, &
2.445134137142996_8, 3.754408661907416_8 /)
! The rational approximation used here is from an unpublished work at
! http://home.online.no/~pjacklam/notes/invnorm/
if (p < p_low) then
! Rational approximation for lower region.
q = sqrt(-TWO*log(p))
z = (((((c(1)*q + c(2))*q + c(3))*q + c(4))*q + c(5))*q + c(6)) / &
((((d(1)*q + d(2))*q + d(3))*q + d(4))*q + ONE)
elseif (p <= ONE - p_low) then
! Rational approximation for central region
q = p - HALF
r = q*q
z = (((((a(1)*r + a(2))*r + a(3))*r + a(4))*r + a(5))*r + a(6))*q / &
(((((b(1)*r + b(2))*r + b(3))*r + b(4))*r + b(5))*r + ONE)
else
! Rational approximation for upper region
q = sqrt(-TWO*log(ONE - p))
z = -(((((c(1)*q + c(2))*q + c(3))*q + c(4))*q + c(5))*q + c(6)) / &
((((d(1)*q + d(2))*q + d(3))*q + d(4))*q + ONE)
endif
! Refinement based on Newton's method
#ifndef NO_F2008
z = z - (HALF * erfc(-z/sqrt(TWO)) - p) * sqrt(TWO*PI) * exp(HALF*z*z)
#endif
end function normal_percentile
!===============================================================================
! T_PERCENTILE calculates the percentile of the Student's t distribution with a
! specified probability level and number of degrees of freedom
!===============================================================================
elemental function t_percentile(p, df) result(t)
real(8), intent(in) :: p ! probability level
integer, intent(in) :: df ! degrees of freedom
real(8) :: t ! corresponding t-value
real(8) :: n ! degrees of freedom as a real(8)
real(8) :: k ! n - 2
real(8) :: z ! percentile of normal distribution
real(8) :: z2 ! z * z
if (df == 1) then
! For one degree of freedom, the t-distribution becomes a Cauchy
! distribution whose cdf we can invert directly
t = tan(PI*(p - HALF))
elseif (df == 2) then
! For two degrees of freedom, the cdf is given by 1/2 + x/(2*sqrt(x^2 +
! 2)). This can be directly inverted to yield the solution below
t = TWO*sqrt(TWO)*(p - HALF)/sqrt(ONE - FOUR*(p - HALF)**2)
else
! This approximation is from E. Olusegun George and Meenakshi Sivaram, "A
! modification of the Fisher-Cornish approximation for the student t
! percentiles," Communication in Statistics - Simulation and Computation,
! 16 (4), pp. 1123-1132 (1987).
n = real(df,8)
k = ONE/(n - TWO)
z = normal_percentile(p)
z2 = z * z
t = sqrt(n*k) * (z + (z2 - THREE)*z*k/FOUR + ((5._8*z2 - 56._8)*z2 + &
75._8)*z*k*k/96._8 + (((z2 - 27._8)*THREE*z2 + 417._8)*z2 - 315._8) &
*z*k*k*k/384._8)
end if
end function t_percentile
!===============================================================================
! CALC_PN calculates the n-th order Legendre polynomial at the value of x.
! Since this function is called repeatedly during the neutron transport process,
! neither n or x is checked to see if they are in the applicable range.
! This is left to the client developer to use where applicable. x is to be in
! the domain of [-1,1], and 0<=n<=5. If x is outside of the range, the return
! value will be outside the expected range; if n is outside the stated range,
! the return value will be 1.0.
!===============================================================================
elemental function calc_pn(n,x) result(pnx)
integer, intent(in) :: n ! Legendre order requested
real(8), intent(in) :: x ! Independent variable the Legendre is to be
! evaluated at; x must be in the domain [-1,1]
real(8) :: pnx ! The Legendre poly of order n evaluated at x
select case(n)
case(1)
pnx = x
case(2)
pnx = 1.5_8 * x * x - HALF
case(3)
pnx = 2.5_8 * x * x * x - 1.5_8 * x
case(4)
pnx = 4.375_8 * (x ** 4) - 3.75_8 * x * x + 0.375_8
case(5)
pnx = 7.875_8 * (x ** 5) - 8.75_8 * x * x * x + 1.875 * x
case(6)
pnx = 14.4375_8 * (x ** 6) - 19.6875_8 * (x ** 4) + &
6.5625_8 * x * x - 0.3125_8
case(7)
pnx = 26.8125_8 * (x ** 7) - 43.3125_8 * (x ** 5) + &
19.6875_8 * x * x * x - 2.1875_8 * x
case(8)
pnx = 50.2734375_8 * (x ** 8) - 93.84375_8 * (x ** 6) + &
54.140625 * (x ** 4) - 9.84375_8 * x * x + 0.2734375_8
case(9)
pnx = 94.9609375_8 * (x ** 9) - 201.09375_8 * (x ** 7) + &
140.765625_8 * (x ** 5) - 36.09375_8 * x * x * x + 2.4609375_8 * x
case(10)
pnx = 180.42578125_8 * (x ** 10) - 427.32421875_8 * (x ** 8) + &
351.9140625_8 * (x ** 6) - 117.3046875_8 * (x ** 4) + &
13.53515625_8 * x * x - 0.24609375_8
case default
pnx = ONE ! correct for case(0), incorrect for the rest
end select
end function calc_pn
!===============================================================================
! CALC_RN calculates the n-th order real spherical harmonics for a given angle
! (in terms of (u,v,w)). All Rn,m values are provided (where -n<=m<=n)
!===============================================================================
pure function calc_rn(n,uvw) result(rn)
integer, intent(in) :: n ! Order requested
real(8), intent(in) :: uvw(3) ! Direction of travel, assumed to be on unit sphere
real(8) :: rn(2*n + 1) ! The resultant R_n(uvw)
real(8) :: phi, w ! Azimuthal and Cosine of Polar angles (from uvw)
real(8) :: w2m1 ! (w^2 - 1), frequently used in these
w = uvw(3) ! z = cos(polar)
if (uvw(1) == ZERO) then
phi = ZERO
else
phi = atan2(uvw(2), uvw(1))
end if
w2m1 = (ONE - w**2)
select case(n)
case (0)
! l = 0, m = 0
rn(1) = ONE
case (1)
! l = 1, m = -1
rn(1) = -(ONE*sqrt(w2m1) * sin(phi))
! l = 1, m = 0
rn(2) = ONE * w
! l = 1, m = 1
rn(3) = -(ONE*sqrt(w2m1) * cos(phi))
case (2)
! l = 2, m = -2
rn(1) = 0.288675134594813_8 * (-THREE * w**2 + THREE) * sin(TWO*phi)
! l = 2, m = -1
rn(2) = -(1.73205080756888_8 * w*sqrt(w2m1) * sin(phi))
! l = 2, m = 0
rn(3) = 1.5_8 * w**2 - HALF
! l = 2, m = 1
rn(4) = -(1.73205080756888_8 * w*sqrt(w2m1) * cos(phi))
! l = 2, m = 2
rn(5) = 0.288675134594813_8 * (-THREE * w**2 + THREE) * cos(TWO*phi)
case (3)
! l = 3, m = -3
rn(1) = -(0.790569415042095_8 * (w2m1)**(THREE/TWO) * sin(THREE * phi))
! l = 3, m = -2
rn(2) = 1.93649167310371_8 * w*(w2m1) * sin(TWO*phi)
! l = 3, m = -1
rn(3) = -(0.408248290463863_8*sqrt(w2m1)*((15.0_8/TWO)*w**2 - THREE/TWO) * &
sin(phi))
! l = 3, m = 0
rn(4) = 2.5_8 * w**3 - 1.5_8 * w
! l = 3, m = 1
rn(5) = -(0.408248290463863_8*sqrt(w2m1)*((15.0_8/TWO)*w**2 - THREE/TWO) * &
cos(phi))
! l = 3, m = 2
rn(6) = 1.93649167310371_8 * w*(w2m1) * cos(TWO*phi)
! l = 3, m = 3
rn(7) = -(0.790569415042095_8 * (w2m1)**(THREE/TWO) * cos(THREE* phi))
case (4)
! l = 4, m = -4
rn(1) = 0.739509972887452_8 * (w2m1)**2 * sin(4.0_8*phi)
! l = 4, m = -3
rn(2) = -(2.09165006633519_8 * w*(w2m1)**(THREE/TWO) * sin(THREE* phi))
! l = 4, m = -2
rn(3) = 0.074535599249993_8 * (w2m1)*((105.0_8/TWO)*w**2 - 15.0_8/TWO) * &
sin(TWO*phi)
! l = 4, m = -1
rn(4) = -(0.316227766016838_8*sqrt(w2m1)*((35.0_8/TWO)*w**3 - 15.0_8/TWO*w)&
* sin(phi))
! l = 4, m = 0
rn(5) = 4.375_8 * w**4 - 3.75_8 * w**2 + 0.375_8
! l = 4, m = 1
rn(6) = -(0.316227766016838_8*sqrt(w2m1)*((35.0_8/TWO)*w**3 - 15.0_8/TWO*w)&
* cos(phi))
! l = 4, m = 2
rn(7) = 0.074535599249993_8 * (w2m1)*((105.0_8/TWO)*w**2 - 15.0_8/TWO) * &
cos(TWO*phi)
! l = 4, m = 3
rn(8) = -(2.09165006633519_8 * w*(w2m1)**(THREE/TWO) * cos(THREE* phi))
! l = 4, m = 4
rn(9) = 0.739509972887452_8 * (w2m1)**2 * cos(4.0_8*phi)
case (5)
! l = 5, m = -5
rn(1) = -(0.701560760020114_8 * (w2m1)**(5.0_8/TWO) * sin(5.0_8*phi))
! l = 5, m = -4
rn(2) = 2.21852991866236_8 * w*(w2m1)**2 * sin(4.0_8*phi)
! l = 5, m = -3
rn(3) = -(0.00996023841111995_8 * (w2m1)**(THREE/TWO)* &
((945.0_8 /TWO)*w**2 - 105.0_8/TWO) * sin(THREE*phi))
! l = 5, m = -2
rn(4) = 0.0487950036474267_8 * (w2m1) &
* ((315.0_8/TWO)*w**3 - 105.0_8/TWO*w) * sin(TWO*phi)
! l = 5, m = -1
rn(5) = -(0.258198889747161_8*sqrt(w2m1)* &
((315.0_8/8.0_8)*w**4 - 105.0_8/4.0_8 * w**2 + 15.0_8/8.0_8) &
* sin(phi))
! l = 5, m = 0
rn(6) = 7.875_8 * w**5 - 8.75_8 * w**3 + 1.875_8 * w
! l = 5, m = 1
rn(7) = -(0.258198889747161_8*sqrt(w2m1)* &
((315.0_8/8.0_8)*w**4 - 105.0_8/4.0_8 * w**2 + 15.0_8/8.0_8) &
* cos(phi))
! l = 5, m = 2
rn(8) = 0.0487950036474267_8 * (w2m1)* &
((315.0_8/TWO)*w**3 - 105.0_8/TWO*w) * cos(TWO*phi)
! l = 5, m = 3
rn(9) = -(0.00996023841111995_8 * (w2m1)**(THREE/TWO)* &
((945.0_8 /TWO)*w**2 - 105.0_8/TWO) * cos(THREE*phi))
! l = 5, m = 4
rn(10) = 2.21852991866236_8 * w*(w2m1)**2 * cos(4.0_8*phi)
! l = 5, m = 5
rn(11) = -(0.701560760020114_8 * (w2m1)**(5.0_8/TWO) * cos(5.0_8* phi))
case (6)
! l = 6, m = -6
rn(1) = 0.671693289381396_8 * (w2m1)**3 * sin(6.0_8*phi)
! l = 6, m = -5
rn(2) = -(2.32681380862329_8 * w*(w2m1)**(5.0_8/TWO) * sin(5.0_8*phi))
! l = 6, m = -4
rn(3) = 0.00104990131391452_8 * (w2m1)**2 * &
((10395.0_8/TWO)*w**2 - 945.0_8/TWO) * sin(4.0_8*phi)
! l = 6, m = -3
rn(4) = -(0.00575054632785295_8 * (w2m1)**(THREE/TWO) * &
((3465.0_8/TWO)*w**3 - 945.0_8/TWO*w) * sin(THREE*phi))
! l = 6, m = -2
rn(5) = 0.0345032779671177_8 * (w2m1) * &
((3465.0_8/8.0_8)*w**4 - 945.0_8/4.0_8 * w**2 + 105.0_8/8.0_8) &
* sin(TWO*phi)
! l = 6, m = -1
rn(6) = -(0.218217890235992_8*sqrt(w2m1) * &
((693.0_8/8.0_8)*w**5- 315.0_8/4.0_8 * w**3 + (105.0_8/8.0_8)*w) &
* sin(phi))
! l = 6, m = 0
rn(7) = 14.4375_8 * w**6 - 19.6875_8 * w**4 + 6.5625_8 * w**2 - 0.3125_8
! l = 6, m = 1
rn(8) = -(0.218217890235992_8*sqrt(w2m1) * &
((693.0_8/8.0_8)*w**5- 315.0_8/4.0_8 * w**3 + (105.0_8/8.0_8)*w) &
* cos(phi))
! l = 6, m = 2
rn(9) = 0.0345032779671177_8 * (w2m1) * &
((3465.0_8/8.0_8)*w**4 -945.0_8/4.0_8 * w**2 + 105.0_8/8.0_8) &
* cos(TWO*phi)
! l = 6, m = 3
rn(10) = -(0.00575054632785295_8 * (w2m1)**(THREE/TWO) * &
((3465.0_8/TWO)*w**3 - 945.0_8/TWO*w) * cos(THREE*phi))
! l = 6, m = 4
rn(11) = 0.00104990131391452_8 * (w2m1)**2 * &
((10395.0_8/TWO)*w**2 - 945.0_8/TWO) * cos(4.0_8*phi)
! l = 6, m = 5
rn(12) = -(2.32681380862329_8 * w*(w2m1)**(5.0_8/TWO) * cos(5.0_8*phi))
! l = 6, m = 6
rn(13) = 0.671693289381396_8 * (w2m1)**3 * cos(6.0_8*phi)
case (7)
! l = 7, m = -7
rn(1) = -(0.647259849287749_8 * (w2m1)**(7.0_8/TWO) * sin(7.0_8*phi))
! l = 7, m = -6
rn(2) = 2.42182459624969_8 * w*(w2m1)**3 * sin(6.0_8*phi)
! l = 7, m = -5
rn(3) = -(9.13821798555235d-5*(w2m1)**(5.0_8/TWO)* &
((135135.0_8/TWO)*w**2 - 10395.0_8/TWO) * sin(5.0_8*phi))
! l = 7, m = -4
rn(4) = 0.000548293079133141_8 * (w2m1)**2* &
((45045.0_8/TWO)*w**3 - 10395.0_8/TWO*w) * sin(4.0_8*phi)
! l = 7, m = -3
rn(5) = -(0.00363696483726654_8 * (w2m1)**(THREE/TWO)* &
((45045.0_8/8.0_8)*w**4 - 10395.0_8/4.0_8 * w**2 + 945.0_8/8.0_8)* &
sin(THREE*phi))
! l = 7, m = -2
rn(6) = 0.025717224993682_8 * (w2m1)* &
((9009.0_8/8.0_8)*w**5 -3465.0_8/4.0_8 * w**3 + (945.0_8/8.0_8)*w)* &
sin(TWO*phi)
! l = 7, m = -1
rn(7) = -(0.188982236504614_8*sqrt(w2m1)* &
((3003.0_8/16.0_8)*w**6 - 3465.0_8/16.0_8 * w**4 + &
(945.0_8/16.0_8)*w**2 - 35.0_8/16.0_8) * sin(phi))
! l = 7, m = 0
rn(8) = 26.8125_8 * w**7 - 43.3125_8 * w**5 + 19.6875_8 * w**3 -2.1875_8 &
* w
! l = 7, m = 1
rn(9) = -(0.188982236504614_8*sqrt(w2m1)* &
((3003.0_8/16.0_8)*w**6 - 3465.0_8/16.0_8 * w**4 + &
(945.0_8/16.0_8)*w**2 - 35.0_8/16.0_8) * cos(phi))
! l = 7, m = 2
rn(10) = 0.025717224993682_8 * (w2m1)* &
((9009.0_8/8.0_8)*w**5 -3465.0_8/4.0_8 * w**3 + (945.0_8/8.0_8)*w)* &
cos(TWO*phi)
! l = 7, m = 3
rn(11) = -(0.00363696483726654_8 * (w2m1)**(THREE/TWO)* &
((45045.0_8/8.0_8)*w**4 - 10395.0_8/4.0_8 * w**2 + 945.0_8/8.0_8)* &
cos(THREE*phi))
! l = 7, m = 4
rn(12) = 0.000548293079133141_8 * (w2m1)**2 * &
((45045.0_8/TWO)*w**3 - 10395.0_8/TWO*w) * cos(4.0_8*phi)
! l = 7, m = 5
rn(13) = -(9.13821798555235d-5*(w2m1)**(5.0_8/TWO)* &
((135135.0_8/TWO)*w**2 - 10395.0_8/TWO) * cos(5.0_8*phi))
! l = 7, m = 6
rn(14) = 2.42182459624969_8 * w*(w2m1)**3 * cos(6.0_8*phi)
! l = 7, m = 7
rn(15) = -(0.647259849287749_8 * (w2m1)**(7.0_8/TWO) * cos(7.0_8*phi))
case (8)
! l = 8, m = -8
rn(1) = 0.626706654240044_8 * (w2m1)**4 * sin(8.0_8*phi)
! l = 8, m = -7
rn(2) = -(2.50682661696018_8 * w*(w2m1)**(7.0_8/TWO) * sin(7.0_8*phi))
! l = 8, m = -6
rn(3) = 6.77369783729086d-6*(w2m1)**3* &
((2027025.0_8/TWO)*w**2 - 135135.0_8/TWO) * sin(6.0_8*phi)
! l = 8, m = -5
rn(4) = -(4.38985792528482d-5*(w2m1)**(5.0_8/TWO)* &
((675675.0_8/TWO)*w**3 - 135135.0_8/TWO*w) * sin(5.0_8*phi))
! l = 8, m = -4
rn(5) = 0.000316557156832328_8 * (w2m1)**2* &
((675675.0_8/8.0_8)*w**4 - 135135.0_8/4.0_8 * w**2 &
+ 10395.0_8/8.0_8) * sin(4.0_8*phi)
! l = 8, m = -3
rn(6) = -(0.00245204119306875_8 * (w2m1)**(THREE/TWO)* &
((135135.0_8/8.0_8)*w**5 - 45045.0_8/4.0_8 * w**3 &
+ (10395.0_8/8.0_8)*w) * sin(THREE*phi))
! l = 8, m = -2
rn(7) = 0.0199204768222399_8 * (w2m1)* &
((45045.0_8/16.0_8)*w**6- 45045.0_8/16.0_8 * w**4 + &
(10395.0_8/16.0_8)*w**2 - 315.0_8/16.0_8) * sin(TWO*phi)
! l = 8, m = -1
rn(8) = -(0.166666666666667_8*sqrt(w2m1)* &
((6435.0_8/16.0_8)*w**7 - 9009.0_8/16.0_8 * w**5 + &
(3465.0_8/16.0_8)*w**3 - 315.0_8/16.0_8 * w) * sin(phi))
! l = 8, m = 0
rn(9) = 50.2734375_8 * w**8 - 93.84375_8 * w**6 + 54.140625_8 * w**4 -&
9.84375_8 * w**2 + 0.2734375_8
! l = 8, m = 1
rn(10) = -(0.166666666666667_8*sqrt(w2m1)* &
((6435.0_8/16.0_8)*w**7 - 9009.0_8/16.0_8 * w**5 + &
(3465.0_8/16.0_8)*w**3 - 315.0_8/16.0_8 * w) * cos(phi))
! l = 8, m = 2
rn(11) = 0.0199204768222399_8 * (w2m1)*((45045.0_8/16.0_8)*w**6- &
45045.0_8/16.0_8 * w**4 + (10395.0_8/16.0_8)*w**2 - &
315.0_8/16.0_8) * cos(TWO*phi)
! l = 8, m = 3
rn(12) = -(0.00245204119306875_8 * (w2m1)**(THREE/TWO)* &
((135135.0_8/8.0_8)*w**5 - 45045.0_8/4.0_8 * w**3 + &
(10395.0_8/8.0_8)*w) * cos(THREE*phi))
! l = 8, m = 4
rn(13) = 0.000316557156832328_8 * (w2m1)**2*((675675.0_8/8.0_8)*w**4 - &
135135.0_8/4.0_8 * w**2 + 10395.0_8/8.0_8) * cos(4.0_8*phi)
! l = 8, m = 5
rn(14) = -(4.38985792528482d-5*(w2m1)**(5.0_8/TWO)*((675675.0_8/TWO)*w**3 -&
135135.0_8/TWO*w) * cos(5.0_8*phi))
! l = 8, m = 6
rn(15) = 6.77369783729086d-6*(w2m1)**3*((2027025.0_8/TWO)*w**2 - &
135135.0_8/TWO) * cos(6.0_8*phi)
! l = 8, m = 7
rn(16) = -(2.50682661696018_8 * w*(w2m1)**(7.0_8/TWO) * cos(7.0_8*phi))
! l = 8, m = 8
rn(17) = 0.626706654240044_8 * (w2m1)**4 * cos(8.0_8*phi)
case (9)
! l = 9, m = -9
rn(1) = -(0.609049392175524_8 * (w2m1)**(9.0_8/TWO) * sin(9.0_8*phi))
! l = 9, m = -8
rn(2) = 2.58397773170915_8 * w*(w2m1)**4 * sin(8.0_8*phi)
! l = 9, m = -7
rn(3) = -(4.37240315267812d-7*(w2m1)**(7.0_8/TWO)* &
((34459425.0_8/TWO)*w**2 - 2027025.0_8/TWO) * sin(7.0_8*phi))
! l = 9, m = -6
rn(4) = 3.02928976464514d-6*(w2m1)**3* &
((11486475.0_8/TWO)*w**3 - 2027025.0_8/TWO*w) * sin(6.0_8*phi)
! l = 9, m = -5
rn(5) = -(2.34647776186144d-5*(w2m1)**(5.0_8/TWO)* &
((11486475.0_8/8.0_8)*w**4 - 2027025.0_8/4.0_8 * w**2 + &
135135.0_8/8.0_8) * sin(5.0_8*phi))
! l = 9, m = -4
rn(6) = 0.000196320414650061_8 * (w2m1)**2*((2297295.0_8/8.0_8)*w**5 - &
675675.0_8/4.0_8 * w**3 + (135135.0_8/8.0_8)*w) * sin(4.0_8*phi)
! l = 9, m = -3
rn(7) = -(0.00173385495536766_8 * (w2m1)**(THREE/TWO)* &
((765765.0_8/16.0_8)*w**6 - 675675.0_8/16.0_8 * w**4 + &
(135135.0_8/16.0_8)*w**2 - 3465.0_8/16.0_8) * sin(THREE*phi))
! l = 9, m = -2
rn(8) = 0.0158910431540932_8 * (w2m1)*((109395.0_8/16.0_8)*w**7- &
135135.0_8/16.0_8 * w**5 + (45045.0_8/16.0_8)*w**3 &
- 3465.0_8/16.0_8 * w) * sin(TWO*phi)
! l = 9, m = -1
rn(9) = -(0.149071198499986_8*sqrt(w2m1)*((109395.0_8/128.0_8)*w**8 - &
45045.0_8/32.0_8 * w**6 + (45045.0_8/64.0_8)*w**4 - 3465.0_8/32.0_8 &
* w**2 + 315.0_8/128.0_8) * sin(phi))
! l = 9, m = 0
rn(10) = 94.9609375_8 * w**9 - 201.09375_8 * w**7 + 140.765625_8 * w**5- &
36.09375_8 * w**3 + 2.4609375_8 * w
! l = 9, m = 1
rn(11) = -(0.149071198499986_8*sqrt(w2m1)*((109395.0_8/128.0_8)*w**8 - &
45045.0_8/32.0_8 * w**6 + (45045.0_8/64.0_8)*w**4 -3465.0_8/32.0_8 &
* w**2 + 315.0_8/128.0_8) * cos(phi))
! l = 9, m = 2
rn(12) = 0.0158910431540932_8 * (w2m1)*((109395.0_8/16.0_8)*w**7 - &
135135.0_8/16.0_8 * w**5 + (45045.0_8/16.0_8)*w**3 &
- 3465.0_8/ 16.0_8 * w) * cos(TWO*phi)
! l = 9, m = 3
rn(13) = -(0.00173385495536766_8 * (w2m1)**(THREE/TWO)*((765765.0_8/16.0_8)&
*w**6 - 675675.0_8/16.0_8 * w**4 + (135135.0_8/16.0_8)*w**2 &
- 3465.0_8/16.0_8)* cos(THREE*phi))
! l = 9, m = 4
rn(14) = 0.000196320414650061_8 * (w2m1)**2*((2297295.0_8/8.0_8)*w**5 - &
675675.0_8/4.0_8 * w**3 + (135135.0_8/8.0_8)*w) * cos(4.0_8*phi)
! l = 9, m = 5
rn(15) = -(2.34647776186144d-5*(w2m1)**(5.0_8/TWO)*((11486475.0_8/8.0_8)* &
w**4 - 2027025.0_8/4.0_8 * w**2 + 135135.0_8/8.0_8) * cos(5.0_8*phi))
! l = 9, m = 6
rn(16) = 3.02928976464514d-6*(w2m1)**3*((11486475.0_8/TWO)*w**3 - &
2027025.0_8/TWO*w) * cos(6.0_8*phi)
! l = 9, m = 7
rn(17) = -(4.37240315267812d-7*(w2m1)**(7.0_8/TWO)* &
((34459425.0_8/TWO)*w**2 - 2027025.0_8/TWO) * cos(7.0_8*phi))
! l = 9, m = 8
rn(18) = 2.58397773170915_8 * w*(w2m1)**4 * cos(8.0_8*phi)
! l = 9, m = 9
rn(19) = -(0.609049392175524_8 * (w2m1)**(9.0_8/TWO) * cos(9.0_8*phi))
case (10)
! l = 10, m = -10
rn(1) = 0.593627917136573_8 * (w2m1)**5 * sin(10.0_8*phi)
! l = 10, m = -9
rn(2) = -(2.65478475211798_8 * w*(w2m1)**(9.0_8/TWO) * sin(9.0_8*phi))
! l = 10, m = -8
rn(3) = 2.49953651452314d-8*(w2m1)**4*((654729075.0_8/TWO)*w**2 - &
34459425.0_8/TWO) * sin(8.0_8*phi)
! l = 10, m = -7
rn(4) = -(1.83677671621093d-7*(w2m1)**(7.0_8/TWO)* &
((218243025.0_8/TWO)*w**3 - 34459425.0_8/TWO*w) * sin(7.0_8*phi))
! l = 10, m = -6
rn(5) = 1.51464488232257d-6*(w2m1)**3*((218243025.0_8/8.0_8)*w**4 - &
34459425.0_8/4.0_8 * w**2 + 2027025.0_8/8.0_8) * sin(6.0_8*phi)
! l = 10, m = -5
rn(6) = -(1.35473956745817d-5*(w2m1)**(5.0_8/TWO)* &
((43648605.0_8/8.0_8)*w**5 - 11486475.0_8/4.0_8 * w**3 + &
(2027025.0_8/8.0_8)*w) * sin(5.0_8*phi))
! l = 10, m = -4
rn(7) = 0.000128521880085575_8 * (w2m1)**2*((14549535.0_8/16.0_8)*w**6 - &
11486475.0_8/16.0_8 * w**4 + (2027025.0_8/16.0_8)*w**2 - &
45045.0_8/16.0_8) * sin(4.0_8*phi)
! l = 10, m = -3
rn(8) = -(0.00127230170115096_8 * (w2m1)**(THREE/TWO)* &
((2078505.0_8/16.0_8)*w**7 - 2297295.0_8/16.0_8 * w**5 + &
(675675.0_8/16.0_8)*w**3 - 45045.0_8/16.0_8 * w) * sin(THREE*phi))
! l = 10, m = -2
rn(9) = 0.012974982402692_8 * (w2m1)*((2078505.0_8/128.0_8)*w**8 - &
765765.0_8/32.0_8 * w**6 + (675675.0_8/64.0_8)*w**4 - &
45045.0_8/32.0_8 * w**2 + 3465.0_8/128.0_8) * sin(TWO*phi)
! l = 10, m = -1
rn(10) = -(0.134839972492648_8*sqrt(w2m1)*((230945.0_8/128.0_8)*w**9 - &
109395.0_8/32.0_8 * w**7 + (135135.0_8/64.0_8)*w**5 - &
15015.0_8/32.0_8 * w**3 + (3465.0_8/128.0_8)*w) * sin(phi))
! l = 10, m = 0
rn(11) = 180.42578125_8 * w**10 - 427.32421875_8 * w**8 +351.9140625_8 &
* w**6 - 117.3046875_8 * w**4 + 13.53515625_8 * w**2 -0.24609375_8
! l = 10, m = 1
rn(12) = -(0.134839972492648_8*sqrt(w2m1)*((230945.0_8/128.0_8)*w**9 - &
109395.0_8/32.0_8 * w**7 + (135135.0_8/64.0_8)*w**5 -15015.0_8/ &
32.0_8 * w**3 + (3465.0_8/128.0_8)*w) * cos(phi))
! l = 10, m = 2
rn(13) = 0.012974982402692_8 * (w2m1)*((2078505.0_8/128.0_8)*w**8 - &
765765.0_8/32.0_8 * w**6 + (675675.0_8/64.0_8)*w**4 -&
45045.0_8/32.0_8 * w**2 + 3465.0_8/128.0_8) * cos(TWO*phi)
! l = 10, m = 3
rn(14) = -(0.00127230170115096_8 * (w2m1)**(THREE/TWO)* &
((2078505.0_8/16.0_8)*w**7 - 2297295.0_8/16.0_8 * w**5 + &
(675675.0_8/16.0_8)*w**3 - 45045.0_8/16.0_8 * w) * cos(THREE*phi))
! l = 10, m = 4
rn(15) = 0.000128521880085575_8 * (w2m1)**2*((14549535.0_8/16.0_8)*w**6 -&
11486475.0_8/16.0_8 * w**4 + (2027025.0_8/16.0_8)*w**2 - &
45045.0_8/16.0_8) * cos(4.0_8*phi)
! l = 10, m = 5
rn(16) = -(1.35473956745817d-5*(w2m1)**(5.0_8/TWO)* &
((43648605.0_8/8.0_8)*w**5 - 11486475.0_8/4.0_8 * w**3 + &
(2027025.0_8/8.0_8)*w) * cos(5.0_8*phi))
! l = 10, m = 6
rn(17) = 1.51464488232257d-6*(w2m1)**3*((218243025.0_8/8.0_8)*w**4 - &
34459425.0_8/4.0_8 * w**2 + 2027025.0_8/8.0_8) * cos(6.0_8*phi)
! l = 10, m = 7
rn(18) = -(1.83677671621093d-7*(w2m1)**(7.0_8/TWO)* &
((218243025.0_8/TWO)*w**3 - 34459425.0_8/TWO*w) * cos(7.0_8*phi))
! l = 10, m = 8
rn(19) = 2.49953651452314d-8*(w2m1)**4* &
((654729075.0_8/TWO)*w**2 - 34459425.0_8/TWO) * cos(8.0_8*phi)
! l = 10, m = 9
rn(20) = -(2.65478475211798_8 * w*(w2m1)**(9.0_8/TWO) * cos(9.0_8*phi))
! l = 10, m = 10
rn(21) = 0.593627917136573_8 * (w2m1)**5 * cos(10.0_8*phi)
case default
rn = ONE
end select
end function calc_rn
!===============================================================================
! CALC_ZN calculates the n-th order modified Zernike polynomial moment for a
! given angle (rho, theta) location in the unit disk. The normlization of the
! polynomials is such that the integral of Z_pq*Z_pq over the unit disk is
! exactly pi
!===============================================================================
subroutine calc_zn(n, rho, phi, zn)
! This procedure uses the modified Kintner's method for calculating Zernike
! polynomials as outlined in Chong, C. W., Raveendran, P., & Mukundan,
! R. (2003). A comparative analysis of algorithms for fast computation of
! Zernike moments. Pattern Recognition, 36(3), 731-742.
integer, intent(in) :: n ! Maximum order
real(8), intent(in) :: rho ! Radial location in the unit disk
real(8), intent(in) :: phi ! Theta (radians) location in the unit disk
real(8), intent(out) :: zn(:) ! The resulting list of coefficients
real(8) :: sin_phi, cos_phi ! Sine and Cosine of phi
real(8) :: sin_phi_vec(n+1) ! Contains sin(n*phi)
real(8) :: cos_phi_vec(n+1) ! Contains cos(n*phi)
real(8) :: zn_mat(n+1, n+1) ! Matrix form of the coefficients which is
! easier to work with
real(8) :: k1, k2, k3, k4 ! Variables for R_m_n calculation
integer :: i,p,q ! Loop counters
! n == radial degree
! m == azimuthal frequency
! ==========================================================================
! Determine vector of sin(n*phi) and cos(n*phi). This takes advantage of the
! following recurrence relations so that only a single sin/cos have to be
! evaluated (http://mathworld.wolfram.com/Multiple-AngleFormulas.html)
!
! sin(nx) = 2 cos(x) sin((n-1)x) - sin((n-2)x)
! cos(nx) = 2 cos(x) cos((n-1)x) - cos((n-2)x)
sin_phi = sin(phi)
cos_phi = cos(phi)
sin_phi_vec(1) = 1.0_8
cos_phi_vec(1) = 1.0_8
sin_phi_vec(2) = 2.0_8 * cos_phi
cos_phi_vec(2) = cos_phi
do i = 3, n+1
sin_phi_vec(i) = 2.0_8 * cos_phi * sin_phi_vec(i-1) - sin_phi_vec(i-2)
cos_phi_vec(i) = 2.0_8 * cos_phi * cos_phi_vec(i-1) - cos_phi_vec(i-2)
end do
do i = 1, n+1
sin_phi_vec(i) = sin_phi_vec(i) * sin_phi
end do
! ==========================================================================
! Calculate R_pq(rho)
! Fill the main diagonal first (Eq. 3.9 in Chong)
do p = 0, n
zn_mat(p+1, p+1) = rho**p
end do
! Fill in the second diagonal (Eq. 3.10 in Chong)
do q = 0, n-2
zn_mat(q+2+1, q+1) = (q+2) * zn_mat(q+2+1, q+2+1) - (q+1) * zn_mat(q+1, q+1)
end do
! Fill in the rest of the values using the original results (Eq. 3.8 in Chong)
do p = 4, n
k2 = 2 * p * (p - 1) * (p - 2)
do q = p-4, 0, -2
k1 = (p + q) * (p - q) * (p - 2) / 2
k3 = -q**2*(p - 1) - p * (p - 1) * (p - 2)
k4 = -p * (p + q - 2) * (p - q - 2) / 2
zn_mat(p+1, q+1) = ((k2 * rho**2 + k3) * zn_mat(p-2+1, q+1) + k4 * zn_mat(p-4+1, q+1)) / k1
end do
end do
! Roll into a single vector for easier computation later
! The vector is ordered (0,0), (1,-1), (1,1), (2,-2), (2,0),
! (2, 2), .... in (n,m) indices
! Note that the cos and sin vectors are offset by one
! sin_phi_vec = [sin(x), sin(2x), sin(3x) ...]
! cos_phi_vec = [1.0, cos(x), cos(2x)... ]
i = 1
do p = 0, n
do q = -p, p, 2
if (q < 0) then
zn(i) = zn_mat(p+1, abs(q)+1) * sin_phi_vec(abs(q))
else if (q == 0) then
zn(i) = zn_mat(p+1, q+1)
else
zn(i) = zn_mat(p+1, q+1) * cos_phi_vec(abs(q)+1)
end if
i = i + 1
end do
end do
end subroutine calc_zn
!===============================================================================
! EXPAND_HARMONIC expands a given series of real spherical harmonics
!===============================================================================
pure function expand_harmonic(data, order, uvw) result(val)
real(8), intent(in) :: data(:)
integer, intent(in) :: order
real(8), intent(in) :: uvw(3)
real(8) :: val
integer :: l, lm_lo, lm_hi
val = data(1)
lm_lo = 2
lm_hi = 4
do l = 1, order - 1
val = val + sqrt(TWO * real(l,8) + ONE) * &
dot_product(calc_rn(l,uvw), data(lm_lo:lm_hi))
lm_lo = lm_hi + 1
lm_hi = lm_lo + 2 * (l + 1)
end do
end function expand_harmonic
!===============================================================================
! EVALUATE_LEGENDRE Find the value of f(x) given a set of Legendre coefficients
! and the value of x
!===============================================================================
pure function evaluate_legendre(data, x) result(val)
real(8), intent(in) :: data(:)
real(8), intent(in) :: x
real(8) :: val
pure function evaluate_legendre(data, x) result(val) bind(C)
real(C_DOUBLE), intent(in) :: data(:)
real(C_DOUBLE), intent(in) :: x
real(C_DOUBLE) :: val
integer :: l
val = HALF * data(1)
do l = 1, size(data) - 1
val = val + (real(l,8) + HALF) * data(l + 1) * calc_pn(l,x)
end do
val = evaluate_legendre_c_intfc(size(data) - 1, data, x)
end function evaluate_legendre
@ -724,108 +137,24 @@ contains
!===============================================================================
function rotate_angle(uvw0, mu, phi) result(uvw)
real(8), intent(in) :: uvw0(3) ! directional cosine
real(8), intent(in) :: mu ! cosine of angle in lab or CM
real(8), optional :: phi ! azimuthal angle
real(8) :: uvw(3) ! rotated directional cosine
real(C_DOUBLE), intent(in) :: uvw0(3) ! directional cosine
real(C_DOUBLE), intent(in) :: mu ! cosine of angle in lab or CM
real(C_DOUBLE), intent(in), optional :: phi ! azimuthal angle
real(8) :: phi_ ! azimuthal angle
real(8) :: sinphi ! sine of azimuthal angle
real(8) :: cosphi ! cosine of azimuthal angle
real(8) :: a ! sqrt(1 - mu^2)
real(8) :: b ! sqrt(1 - w^2)
real(8) :: u0 ! original cosine in x direction
real(8) :: v0 ! original cosine in y direction
real(8) :: w0 ! original cosine in z direction
real(C_DOUBLE) :: uvw(3) ! rotated directional cosine
! Copy original directional cosines
u0 = uvw0(1)
v0 = uvw0(2)
w0 = uvw0(3)
! Sample azimuthal angle in [0,2pi) if none provided
if (present(phi)) then
phi_ = phi
else
phi_ = TWO * PI * prn()
end if
! Precompute factors to save flops
sinphi = sin(phi_)
cosphi = cos(phi_)
a = sqrt(max(ZERO, ONE - mu*mu))
b = sqrt(max(ZERO, ONE - w0*w0))
! Need to treat special case where sqrt(1 - w**2) is close to zero by
! expanding about the v component rather than the w component
if (b > 1e-10) then
uvw(1) = mu*u0 + a*(u0*w0*cosphi - v0*sinphi)/b
uvw(2) = mu*v0 + a*(v0*w0*cosphi + u0*sinphi)/b
uvw(3) = mu*w0 - a*b*cosphi
else
b = sqrt(ONE - v0*v0)
uvw(1) = mu*u0 + a*(u0*v0*cosphi + w0*sinphi)/b
uvw(2) = mu*v0 - a*b*cosphi
uvw(3) = mu*w0 + a*(v0*w0*cosphi - u0*sinphi)/b
end if
uvw = uvw0
call rotate_angle_c_intfc(uvw, mu, phi)
end function rotate_angle
!===============================================================================
! MAXWELL_SPECTRUM samples an energy from the Maxwell fission distribution based
! on a direct sampling scheme. The probability distribution function for a
! Maxwellian is given as p(x) = 2/(T*sqrt(pi))*sqrt(x/T)*exp(-x/T). This PDF can
! be sampled using rule C64 in the Monte Carlo Sampler LA-9721-MS.
!===============================================================================
function maxwell_spectrum(T) result(E_out)
real(8), intent(in) :: T ! tabulated function of incoming E
real(8) :: E_out ! sampled energy
real(8) :: r1, r2, r3 ! random numbers
real(8) :: c ! cosine of pi/2*r3
r1 = prn()
r2 = prn()
r3 = prn()
! determine cosine of pi/2*r
c = cos(PI/TWO*r3)
! determine outgoing energy
E_out = -T*(log(r1) + log(r2)*c*c)
end function maxwell_spectrum
!===============================================================================
! WATT_SPECTRUM samples the outgoing energy from a Watt energy-dependent fission
! spectrum. Although fitted parameters exist for many nuclides, generally the
! continuous tabular distributions (LAW 4) should be used in lieu of the Watt
! spectrum. This direct sampling scheme is an unpublished scheme based on the
! original Watt spectrum derivation (See F. Brown's MC lectures).
!===============================================================================
function watt_spectrum(a, b) result(E_out)
real(8), intent(in) :: a ! Watt parameter a
real(8), intent(in) :: b ! Watt parameter b
real(8) :: E_out ! energy of emitted neutron
real(8) :: w ! sampled from Maxwellian
w = maxwell_spectrum(a)
E_out = w + a*a*b/4. + (TWO*prn() - ONE)*sqrt(a*a*b*w)
end function watt_spectrum
!===============================================================================
! FADDEEVA the Faddeeva function, using Stephen Johnson's implementation
!===============================================================================
function faddeeva(z) result(wv)
complex(C_DOUBLE_COMPLEX), intent(in) :: z ! The point to evaluate Z at
complex(8) :: wv ! The resulting w(z) value
function faddeeva(z) result(wv) bind(C)
complex(C_DOUBLE_COMPLEX), intent(in) :: z ! The point to evaluate Z at
complex(C_DOUBLE_COMPLEX) :: wv ! The resulting w(z) value
real(C_DOUBLE) :: relerr ! Target relative error in inner loop of MIT
! Faddeeva
@ -853,10 +182,10 @@ contains
end function faddeeva
recursive function w_derivative(z, order) result(wv)
recursive function w_derivative(z, order) result(wv) bind(C)
complex(C_DOUBLE_COMPLEX), intent(in) :: z ! The point to evaluate Z at
integer, intent(in) :: order
complex(8) :: wv ! The resulting w(z) value
integer(C_INT), intent(in) :: order
complex(C_DOUBLE_COMPLEX) :: wv ! The resulting w(z) value
select case(order)
case (0)
@ -869,62 +198,4 @@ contains
end select
end function w_derivative
!===============================================================================
! BROADEN_WMP_POLYNOMIALS Doppler broadens the windowed multipole curvefit. The
! curvefit is a polynomial of the form
! a/E + b/sqrt(E) + c + d sqrt(E) ...
!===============================================================================
subroutine broaden_wmp_polynomials(E, dopp, n, factors)
real(8), intent(in) :: E ! Energy to evaluate at
real(8), intent(in) :: dopp ! sqrt(atomic weight ratio / kT),
! kT given in eV.
integer, intent(in) :: n ! number of components to polynomial
real(8), intent(out):: factors(n) ! output leading coefficient
integer :: i
real(8) :: sqrtE ! sqrt(energy)
real(8) :: beta ! sqrt(atomic weight ratio * E / kT)
real(8) :: half_inv_dopp2 ! 0.5 / dopp**2
real(8) :: quarter_inv_dopp4 ! 0.25 / dopp**4
real(8) :: erf_beta ! error function of beta
real(8) :: exp_m_beta2 ! exp(-beta**2)
sqrtE = sqrt(E)
beta = sqrtE * dopp
half_inv_dopp2 = HALF / dopp**2
quarter_inv_dopp4 = half_inv_dopp2**2
if (beta > 6.0_8) then
! Save time, ERF(6) is 1 to machine precision.
! beta/sqrtpi*exp(-beta**2) is also approximately 1 machine epsilon.
erf_beta = ONE
exp_m_beta2 = ZERO
else
erf_beta = erf(beta)
exp_m_beta2 = exp(-beta**2)
end if
! Assume that, for sure, we'll use a second order (1/E, 1/V, const)
! fit, and no less.
factors(1) = erf_beta / E
factors(2) = ONE / sqrtE
factors(3) = factors(1) * (half_inv_dopp2 + E) &
+ exp_m_beta2 / (beta * SQRT_PI)
! Perform recursive broadening of high order components
do i = 1, n-3
if (i /= 1) then
factors(i+3) = -factors(i-1) * (i - ONE) * i * quarter_inv_dopp4 &
+ factors(i+1) * (E + (ONE + TWO * i) * half_inv_dopp2)
else
! Although it's mathematically identical, factors(0) will contain
! nothing, and we don't want to have to worry about memory.
factors(i+3) = factors(i+1)*(E + (ONE + TWO * i) * half_inv_dopp2)
end if
end do
end subroutine broaden_wmp_polynomials
end module math

693
src/math_functions.cpp Normal file
View file

@ -0,0 +1,693 @@
#include "math_functions.h"
namespace openmc {
//==============================================================================
// Mathematical methods
//==============================================================================
double normal_percentile_c(double p) {
constexpr double p_low = 0.02425;
constexpr double a[6] = {-3.969683028665376e1, 2.209460984245205e2,
-2.759285104469687e2, 1.383577518672690e2,
-3.066479806614716e1, 2.506628277459239e0};
constexpr double b[5] = {-5.447609879822406e1, 1.615858368580409e2,
-1.556989798598866e2, 6.680131188771972e1,
-1.328068155288572e1};
constexpr double c[6] = {-7.784894002430293e-3, -3.223964580411365e-1,
-2.400758277161838, -2.549732539343734,
4.374664141464968, 2.938163982698783};
constexpr double d[4] = {7.784695709041462e-3, 3.224671290700398e-1,
2.445134137142996, 3.754408661907416};
// The rational approximation used here is from an unpublished work at
// http://home.online.no/~pjacklam/notes/invnorm/
double z;
double q;
if (p < p_low) {
// Rational approximation for lower region.
q = std::sqrt(-2.0 * std::log(p));
z = (((((c[0]*q + c[1])*q + c[2])*q + c[3])*q + c[4])*q + c[5]) /
((((d[0]*q + d[1])*q + d[2])*q + d[3])*q + 1.0);
} else if (p <= 1.0 - p_low) {
// Rational approximation for central region
q = p - 0.5;
double r = q * q;
z = (((((a[0]*r + a[1])*r + a[2])*r + a[3])*r + a[4])*r + a[5])*q /
(((((b[0]*r + b[1])*r + b[2])*r + b[3])*r + b[4])*r + 1.0);
} else {
// Rational approximation for upper region
q = std::sqrt(-2.0*std::log(1.0 - p));
z = -(((((c[0]*q + c[1])*q + c[2])*q + c[3])*q + c[4])*q + c[5]) /
((((d[0]*q + d[1])*q + d[2])*q + d[3])*q + 1.0);
}
// Refinement based on Newton's method
z = z - (0.5 * std::erfc(-z / std::sqrt(2.0)) - p) * std::sqrt(2.0 * PI) *
std::exp(0.5 * z * z);
return z;
}
double t_percentile_c(double p, int df){
double t;
if (df == 1) {
// For one degree of freedom, the t-distribution becomes a Cauchy
// distribution whose cdf we can invert directly
t = std::tan(PI*(p - 0.5));
} else if (df == 2) {
// For two degrees of freedom, the cdf is given by 1/2 + x/(2*sqrt(x^2 +
// 2)). This can be directly inverted to yield the solution below
t = 2.0 * std::sqrt(2.0)*(p - 0.5) /
std::sqrt(1. - 4. * std::pow(p - 0.5, 2.));
} else {
// This approximation is from E. Olusegun George and Meenakshi Sivaram, "A
// modification of the Fisher-Cornish approximation for the student t
// percentiles," Communication in Statistics - Simulation and Computation,
// 16 (4), pp. 1123-1132 (1987).
double n = df;
double k = 1. / (n - 2.);
double z = normal_percentile_c(p);
double z2 = z * z;
t = std::sqrt(n * k) * (z + (z2 - 3.) * z * k / 4. + ((5. * z2 - 56.) * z2 +
75.) * z * k * k / 96. + (((z2 - 27.) * 3. * z2 + 417.) * z2 - 315.) *
z * k * k * k / 384.);
}
return t;
}
void calc_pn_c(int n, double x, double pnx[]) {
pnx[0] = 1.;
if (n >= 1) {
pnx[1] = x;
}
// Use recursion relation to build the higher orders
for (int l = 1; l < n; l ++) {
pnx[l + 1] = ((2 * l + 1) * x * pnx[l] - l * pnx[l - 1]) / (l + 1);
}
}
double evaluate_legendre_c(int n, const double data[], double x) {
double pnx[n + 1];
double val = 0.0;
calc_pn_c(n, x, pnx);
for (int l = 0; l <= n; l++) {
val += (l + 0.5) * data[l] * pnx[l];
}
return val;
}
void calc_rn_c(int n, const double uvw[3], double rn[]){
// rn[] is assumed to have already been allocated to the correct size
// Store the cosine of the polar angle and the azimuthal angle
double w = uvw[2];
double phi;
if (uvw[0] == 0.) {
phi = 0.;
} else {
phi = std::atan2(uvw[1], uvw[0]);
}
// Store the shorthand of 1-w * w
double w2m1 = 1. - w * w;
// Now evaluate the spherical harmonics function
rn[0] = 1.;
int i = 0;
for (int l = 1; l <= n; l++) {
// Set the index to the start of this order
i += 2 * (l - 1) + 1;
// Now evaluate each
switch (l) {
case 1:
// l = 1, m = -1
rn[i] = -(std::sqrt(w2m1) * std::sin(phi));
// l = 1, m = 0
rn[i + 1] = w;
// l = 1, m = 1
rn[i + 2] = -(std::sqrt(w2m1) * std::cos(phi));
break;
case 2:
// l = 2, m = -2
rn[i] = 0.288675134594813 * (-3. * w * w + 3.) * std::sin(2. * phi);
// l = 2, m = -1
rn[i + 1] = -(1.73205080756888 * w*std::sqrt(w2m1) * std::sin(phi));
// l = 2, m = 0
rn[i + 2] = 1.5 * w * w - 0.5;
// l = 2, m = 1
rn[i + 3] = -(1.73205080756888 * w*std::sqrt(w2m1) * std::cos(phi));
// l = 2, m = 2
rn[i + 4] = 0.288675134594813 * (-3. * w * w + 3.) * std::cos(2. * phi);
break;
case 3:
// l = 3, m = -3
rn[i] = -(0.790569415042095 * std::pow(w2m1, 1.5) * std::sin(3. * phi));
// l = 3, m = -2
rn[i + 1] = 1.93649167310371 * w*(w2m1) * std::sin(2.*phi);
// l = 3, m = -1
rn[i + 2] = -(0.408248290463863*std::sqrt(w2m1)*((7.5)*w * w - 3./2.) *
std::sin(phi));
// l = 3, m = 0
rn[i + 3] = 2.5 * std::pow(w, 3) - 1.5 * w;
// l = 3, m = 1
rn[i + 4] = -(0.408248290463863*std::sqrt(w2m1)*((7.5)*w * w - 3./2.) *
std::cos(phi));
// l = 3, m = 2
rn[i + 5] = 1.93649167310371 * w*(w2m1) * std::cos(2.*phi);
// l = 3, m = 3
rn[i + 6] = -(0.790569415042095 * std::pow(w2m1, 1.5) * std::cos(3.* phi));
break;
case 4:
// l = 4, m = -4
rn[i] = 0.739509972887452 * (w2m1 * w2m1) * std::sin(4.0*phi);
// l = 4, m = -3
rn[i + 1] = -(2.09165006633519 * w * std::pow(w2m1, 1.5) * std::sin(3.* phi));
// l = 4, m = -2
rn[i + 2] = 0.074535599249993 * (w2m1)*(52.5 * w * w - 7.5) * std::sin(2. *phi);
// l = 4, m = -1
rn[i + 3] = -(0.316227766016838*std::sqrt(w2m1)*(17.5 * std::pow(w, 3) - 7.5 * w) *
std::sin(phi));
// l = 4, m = 0
rn[i + 4] = 4.375 * std::pow(w, 4) - 3.75 * w * w + 0.375;
// l = 4, m = 1
rn[i + 5] = -(0.316227766016838*std::sqrt(w2m1)*(17.5 * std::pow(w, 3) - 7.5*w) *
std::cos(phi));
// l = 4, m = 2
rn[i + 6] = 0.074535599249993 * (w2m1)*(52.5*w * w - 7.5) * std::cos(2.*phi);
// l = 4, m = 3
rn[i + 7] = -(2.09165006633519 * w * std::pow(w2m1, 1.5) * std::cos(3.* phi));
// l = 4, m = 4
rn[i + 8] = 0.739509972887452 * w2m1 * w2m1 * std::cos(4.0*phi);
break;
case 5:
// l = 5, m = -5
rn[i] = -(0.701560760020114 * std::pow(w2m1, 2.5) * std::sin(5.0 * phi));
// l = 5, m = -4
rn[i + 1] = 2.21852991866236 * w * w2m1 * w2m1 * std::sin(4.0 * phi);
// l = 5, m = -3
rn[i + 2] = -(0.00996023841111995 * std::pow(w2m1, 1.5) *
((945.0 /2.)* w * w - 52.5) * std::sin(3.*phi));
// l = 5, m = -2
rn[i + 3] = 0.0487950036474267 * (w2m1)
* ((315.0/2.)* std::pow(w, 3) - 52.5 * w) * std::sin(2.*phi);
// l = 5, m = -1
rn[i + 4] = -(0.258198889747161*std::sqrt(w2m1) *
(39.375 * std::pow(w, 4) - 105.0/4.0 * w * w + 15.0/8.0) * std::sin(phi));
// l = 5, m = 0
rn[i + 5] = 7.875 * std::pow(w, 5) - 8.75 * std::pow(w, 3) + 1.875 * w;
// l = 5, m = 1
rn[i + 6] = -(0.258198889747161 * std::sqrt(w2m1)*
(39.375 * std::pow(w, 4) - 105.0/4.0 * w * w + 15.0/8.0) * std::cos(phi));
// l = 5, m = 2
rn[i + 7] = 0.0487950036474267 * (w2m1) *
((315.0 / 2.) * std::pow(w, 3) - 52.5*w) * std::cos(2.*phi);
// l = 5, m = 3
rn[i + 8] = -(0.00996023841111995 * std::pow(w2m1, 1.5) *
((945.0 / 2.) * w * w - 52.5) * std::cos(3.*phi));
// l = 5, m = 4
rn[i + 9] = 2.21852991866236 * w * w2m1 * w2m1 * std::cos(4.0*phi);
// l = 5, m = 5
rn[i + 10] = -(0.701560760020114 * std::pow(w2m1, 2.5) * std::cos(5.0* phi));
break;
case 6:
// l = 6, m = -6
rn[i] = 0.671693289381396 * std::pow(w2m1, 3) * std::sin(6.0*phi);
// l = 6, m = -5
rn[i + 1] = -(2.32681380862329 * w*std::pow(w2m1, 2.5) * std::sin(5.0*phi));
// l = 6, m = -4
rn[i + 2] = 0.00104990131391452 * w2m1 * w2m1 *
((10395.0/2.) * w * w - 945.0/2.) * std::sin(4.0 * phi);
// l = 6, m = -3
rn[i + 3] = -(0.00575054632785295 * std::pow(w2m1, 1.5) *
((3465.0/2.) * std::pow(w, 3) - 945.0/2.*w) * std::sin(3.*phi));
// l = 6, m = -2
rn[i + 4] = 0.0345032779671177 * (w2m1) *
((3465.0/8.0)* std::pow(w, 4) - 945.0/4.0 * w * w + 105.0/8.0) *
std::sin(2. * phi);
// l = 6, m = -1
rn[i + 5] = -(0.218217890235992*std::sqrt(w2m1) *
((693.0/8.0)* std::pow(w, 5)- 315.0/4.0 * std::pow(w, 3) + (105.0/8.0)*w) *
std::sin(phi));
// l = 6, m = 0
rn[i + 6] = 14.4375 * std::pow(w, 6) - 19.6875 * std::pow(w, 4) + 6.5625 * w * w -
0.3125;
// l = 6, m = 1
rn[i + 7] = -(0.218217890235992*std::sqrt(w2m1) *
((693.0/8.0)* std::pow(w, 5)- 315.0/4.0 * std::pow(w, 3) + (105.0/8.0)*w) *
std::cos(phi));
// l = 6, m = 2
rn[i + 8] = 0.0345032779671177 * w2m1 *
((3465.0/8.0)* std::pow(w, 4) -945.0/4.0 * w * w + 105.0/8.0) *
std::cos(2.*phi);
// l = 6, m = 3
rn[i + 9] = -(0.00575054632785295 * std::pow(w2m1, 1.5) *
((3465.0/2.) * std::pow(w, 3) - 945.0/2.*w) * std::cos(3.*phi));
// l = 6, m = 4
rn[i + 10] = 0.00104990131391452 * w2m1 * w2m1 *
((10395.0/2.)*w * w - 945.0/2.) * std::cos(4.0*phi);
// l = 6, m = 5
rn[i + 11] = -(2.32681380862329 * w * std::pow(w2m1, 2.5) * std::cos(5.0*phi));
// l = 6, m = 6
rn[i + 12] = 0.671693289381396 * std::pow(w2m1, 3) * std::cos(6.0*phi);
break;
case 7:
// l = 7, m = -7
rn[i] = -(0.647259849287749 * std::pow(w2m1, 3.5) * std::sin(7.0*phi));
// l = 7, m = -6
rn[i + 1] = 2.42182459624969 * w*std::pow(w2m1, 3) * std::sin(6.0*phi);
// l = 7, m = -5
rn[i + 2] = -(9.13821798555235e-5*std::pow(w2m1, 2.5) *
((135135.0/2.)*w * w - 10395.0/2.) * std::sin(5.0*phi));
// l = 7, m = -4
rn[i + 3] = 0.000548293079133141 * w2m1 * w2m1 *
((45045.0/2.)*std::pow(w, 3) - 10395.0/2.*w) * std::sin(4.0*phi);
// l = 7, m = -3
rn[i + 4] = -(0.00363696483726654 * std::pow(w2m1, 1.5) *
((45045.0/8.0)* std::pow(w, 4) - 10395.0/4.0 * w * w + 945.0/8.0) *
std::sin(3.*phi));
// l = 7, m = -2
rn[i + 5] = 0.025717224993682 * (w2m1) *
((9009.0/8.0)* std::pow(w, 5) -3465.0/4.0 * std::pow(w, 3) + (945.0/8.0)*w) *
std::sin(2.*phi);
// l = 7, m = -1
rn[i + 6] = -(0.188982236504614*std::sqrt(w2m1) *
((3003.0/16.0)* std::pow(w, 6) - 3465.0/16.0 * std::pow(w, 4) +
(945.0/16.0)*w * w - 35.0/16.0) * std::sin(phi));
// l = 7, m = 0
rn[i + 7] = 26.8125 * std::pow(w, 7) - 43.3125 * std::pow(w, 5) + 19.6875 * std::pow(w, 3) -
2.1875 * w;
// l = 7, m = 1
rn[i + 8] = -(0.188982236504614*std::sqrt(w2m1) * ((3003.0/16.0) * std::pow(w, 6) -
3465.0/16.0 * std::pow(w, 4) + (945.0/16.0)*w * w - 35.0/16.0) * std::cos(phi));
// l = 7, m = 2
rn[i + 9] = 0.025717224993682 * (w2m1) * ((9009.0/8.0)* std::pow(w, 5) -
3465.0/4.0 * std::pow(w, 3) + (945.0/8.0)*w) * std::cos(2.*phi);
// l = 7, m = 3
rn[i + 10] = -(0.00363696483726654 * std::pow(w2m1, 1.5) *
((45045.0/8.0)* std::pow(w, 4) - 10395.0/4.0 * w * w + 945.0/8.0) *
std::cos(3.*phi));
// l = 7, m = 4
rn[i + 11] = 0.000548293079133141 * w2m1 * w2m1 *
((45045.0/2.)*std::pow(w, 3) - 10395.0/2.*w) * std::cos(4.0*phi);
// l = 7, m = 5
rn[i + 12] = -(9.13821798555235e-5*std::pow(w2m1, 2.5) *
((135135.0/2.)*w * w - 10395.0/2.) * std::cos(5.0*phi));
// l = 7, m = 6
rn[i + 13] = 2.42182459624969 * w*std::pow(w2m1, 3) * std::cos(6.0*phi);
// l = 7, m = 7
rn[i + 14] = -(0.647259849287749 * std::pow(w2m1, 3.5) * std::cos(7.0*phi));
break;
case 8:
// l = 8, m = -8
rn[i] = 0.626706654240044 * std::pow(w2m1, 4) * std::sin(8.0*phi);
// l = 8, m = -7
rn[i + 1] = -(2.50682661696018 * w*std::pow(w2m1, 3.5) * std::sin(7.0*phi));
// l = 8, m = -6
rn[i + 2] = 6.77369783729086e-6*std::pow(w2m1, 3)*
((2027025.0/2.)*w * w - 135135.0/2.) * std::sin(6.0*phi);
// l = 8, m = -5
rn[i + 3] = -(4.38985792528482e-5*std::pow(w2m1, 2.5) *
((675675.0/2.)*std::pow(w, 3) - 135135.0/2.*w) * std::sin(5.0*phi));
// l = 8, m = -4
rn[i + 4] = 0.000316557156832328 * w2m1 * w2m1 *
((675675.0/8.0)* std::pow(w, 4) - 135135.0/4.0 * w * w + 10395.0/8.0) *
std::sin(4.0*phi);
// l = 8, m = -3
rn[i + 5] = -(0.00245204119306875 * std::pow(w2m1, 1.5) * ((135135.0/8.0) *
std::pow(w, 5) - 45045.0/4.0 * std::pow(w, 3) + (10395.0/8.0)*w) * std::sin(3.*phi));
// l = 8, m = -2
rn[i + 6] = 0.0199204768222399 * (w2m1) *
((45045.0/16.0)* std::pow(w, 6)- 45045.0/16.0 * std::pow(w, 4) +
(10395.0/16.0)*w * w - 315.0/16.0) * std::sin(2.*phi);
// l = 8, m = -1
rn[i + 7] = -(0.166666666666667*std::sqrt(w2m1) *
((6435.0/16.0)* std::pow(w, 7) - 9009.0/16.0 * std::pow(w, 5) +
(3465.0/16.0)*std::pow(w, 3) - 315.0/16.0 * w) * std::sin(phi));
// l = 8, m = 0
rn[i + 8] = 50.2734375 * std::pow(w, 8) - 93.84375 * std::pow(w, 6) + 54.140625 *
std::pow(w, 4) - 9.84375 * w * w + 0.2734375;
// l = 8, m = 1
rn[i + 9] = -(0.166666666666667*std::sqrt(w2m1) *
((6435.0/16.0)* std::pow(w, 7) - 9009.0/16.0 * std::pow(w, 5) +
(3465.0/16.0)*std::pow(w, 3) - 315.0/16.0 * w) * std::cos(phi));
// l = 8, m = 2
rn[i + 10] = 0.0199204768222399 * (w2m1)*((45045.0/16.0)* std::pow(w, 6)-
45045.0/16.0 * std::pow(w, 4) + (10395.0/16.0)*w * w -
315.0/16.0) * std::cos(2.*phi);
// l = 8, m = 3
rn[i + 11] = -(0.00245204119306875 * std::pow(w2m1, 1.5)*
((135135.0/8.0) * std::pow(w, 5) - 45045.0/4.0 * std::pow(w, 3) +
(10395.0/8.0)*w) * std::cos(3.*phi));
// l = 8, m = 4
rn[i + 12] = 0.000316557156832328 * w2m1 * w2m1*((675675.0/8.0)* std::pow(w, 4) -
135135.0/4.0 * w * w + 10395.0/8.0) * std::cos(4.0*phi);
// l = 8, m = 5
rn[i + 13] = -(4.38985792528482e-5*std::pow(w2m1, 2.5)*((675675.0/2.)*std::pow(w, 3) -
135135.0/2.*w) * std::cos(5.0*phi));
// l = 8, m = 6
rn[i + 14] = 6.77369783729086e-6*std::pow(w2m1, 3)*((2027025.0/2.)*w * w -
135135.0/2.) * std::cos(6.0*phi);
// l = 8, m = 7
rn[i + 15] = -(2.50682661696018 * w*std::pow(w2m1, 3.5) * std::cos(7.0*phi));
// l = 8, m = 8
rn[i + 16] = 0.626706654240044 * std::pow(w2m1, 4) * std::cos(8.0*phi);
break;
case 9:
// l = 9, m = -9
rn[i] = -(0.609049392175524 * std::pow(w2m1, 4.5) * std::sin(9.0 * phi));
// l = 9, m = -8
rn[i + 1] = 2.58397773170915 * w*std::pow(w2m1, 4) * std::sin(8.0 * phi);
// l = 9, m = -7
rn[i + 2] = -(4.37240315267812e-7*std::pow(w2m1, 3.5) *
((34459425.0/2.)*w * w - 2027025.0/2.) * std::sin(7.0 * phi));
// l = 9, m = -6
rn[i + 3] = 3.02928976464514e-6*std::pow(w2m1, 3)*
((11486475.0/2.)*std::pow(w, 3) - 2027025.0/2.*w) * std::sin(6.0 * phi);
// l = 9, m = -5
rn[i + 4] = -(2.34647776186144e-5*std::pow(w2m1, 2.5) *
((11486475.0/8.0)* std::pow(w, 4) - 2027025.0 / 4.0 * w * w +
135135.0/8.0) * std::sin(5.0 * phi));
// l = 9, m = -4
rn[i + 5] = 0.000196320414650061 * w2m1 * w2m1*((2297295.0/8.0)* std::pow(w, 5) -
675675.0/4.0 * std::pow(w, 3) + (135135.0/8.0)*w) * std::sin(4.0*phi);
// l = 9, m = -3
rn[i + 6] = -(0.00173385495536766 * std::pow(w2m1, 1.5) *
((765765.0/16.0)* std::pow(w, 6) - 675675.0/16.0 * std::pow(w, 4) +
(135135.0/16.0)*w * w - 3465.0/16.0) * std::sin(3. * phi));
// l = 9, m = -2
rn[i + 7] = 0.0158910431540932 * (w2m1)*((109395.0/16.0)* std::pow(w, 7)-
135135.0/16.0 * std::pow(w, 5) + (45045.0/16.0)*std::pow(w, 3) -
3465.0/16.0 * w) * std::sin(2. * phi);
// l = 9, m = -1
rn[i + 8] = -(0.149071198499986*std::sqrt(w2m1)*((109395.0/128.0)* std::pow(w, 8) -
45045.0/32.0 * std::pow(w, 6) + (45045.0/64.0)* std::pow(w, 4) -
3465.0/32.0 * w * w + 315.0/128.0) * std::sin(phi));
// l = 9, m = 0
rn[i + 9] = 94.9609375 * std::pow(w, 9) - 201.09375 * std::pow(w, 7) +
140.765625 * std::pow(w, 5)- 36.09375 * std::pow(w, 3) + 2.4609375 * w;
// l = 9, m = 1
rn[i + 10] = -(0.149071198499986*std::sqrt(w2m1)*((109395.0/128.0)* std::pow(w, 8) -
45045.0/32.0 * std::pow(w, 6) + (45045.0/64.0)* std::pow(w, 4) -
3465.0/32.0 * w * w + 315.0/128.0) * std::cos(phi));
// l = 9, m = 2
rn[i + 11] = 0.0158910431540932 * (w2m1)*((109395.0/16.0)* std::pow(w, 7) -
135135.0/16.0 * std::pow(w, 5) + (45045.0/16.0)*std::pow(w, 3) -
3465.0/ 16.0 * w) * std::cos(2. * phi);
// l = 9, m = 3
rn[i + 12] = -(0.00173385495536766 * std::pow(w2m1, 1.5)*((765765.0/16.0) *
std::pow(w, 6) - 675675.0/16.0 * std::pow(w, 4) +
(135135.0/16.0)* w * w - 3465.0/16.0)* std::cos(3. * phi));
// l = 9, m = 4
rn[i + 13] = 0.000196320414650061 * w2m1 * w2m1*((2297295.0/8.0) * std::pow(w, 5) -
675675.0/4.0 * std::pow(w, 3) + (135135.0/8.0)*w) * std::cos(4.0 * phi);
// l = 9, m = 5
rn[i + 14] = -(2.34647776186144e-5*std::pow(w2m1, 2.5)*((11486475.0/8.0) *
std::pow(w, 4) - 2027025.0/4.0 * w * w + 135135.0/8.0) *
std::cos(5.0 * phi));
// l = 9, m = 6
rn[i + 15] = 3.02928976464514e-6*std::pow(w2m1, 3)*((11486475.0/2.)*std::pow(w, 3) -
2027025.0/2. * w) * std::cos(6.0 * phi);
// l = 9, m = 7
rn[i + 16] = -(4.37240315267812e-7*std::pow(w2m1, 3.5)*
((34459425.0/2.) * w * w - 2027025.0/2.) * std::cos(7.0 * phi));
// l = 9, m = 8
rn[i + 17] = 2.58397773170915 * w*std::pow(w2m1, 4) * std::cos(8.0 * phi);
// l = 9, m = 9
rn[i + 18] = -(0.609049392175524 * std::pow(w2m1, 4.5) * std::cos(9.0 * phi));
break;
case 10:
// l = 10, m = -10
rn[i] = 0.593627917136573 * std::pow(w2m1, 5) * std::sin(10.0 * phi);
// l = 10, m = -9
rn[i + 1] = -(2.65478475211798 * w * std::pow(w2m1, 4.5) * std::sin(9.0 * phi));
// l = 10, m = -8
rn[i + 2] = 2.49953651452314e-8 * std::pow(w2m1, 4) *
((654729075.0/2.) * w * w - 34459425.0/2.) * std::sin(8.0 * phi);
// l = 10, m = -7
rn[i + 3] = -(1.83677671621093e-7*std::pow(w2m1, 3.5)*
((218243025.0/2.)*std::pow(w, 3) - 34459425.0/2.*w) *
std::sin(7.0 * phi));
// l = 10, m = -6
rn[i + 4] = 1.51464488232257e-6*std::pow(w2m1, 3)*((218243025.0/8.0)* std::pow(w, 4) -
34459425.0/4.0 * w * w + 2027025.0/8.0) * std::sin(6.0 * phi);
// l = 10, m = -5
rn[i + 5] = -(1.35473956745817e-5*std::pow(w2m1, 2.5)*
((43648605.0/8.0)* std::pow(w, 5) - 11486475.0/4.0 * std::pow(w, 3) +
(2027025.0/8.0)*w) * std::sin(5.0 * phi));
// l = 10, m = -4
rn[i + 6] = 0.000128521880085575 * w2m1 * w2m1*((14549535.0/16.0)* std::pow(w, 6) -
11486475.0/16.0 * std::pow(w, 4) + (2027025.0/16.0)*w * w -
45045.0/16.0) * std::sin(4.0 * phi);
// l = 10, m = -3
rn[i + 7] = -(0.00127230170115096 * std::pow(w2m1, 1.5)*
((2078505.0/16.0)* std::pow(w, 7) - 2297295.0/16.0 * std::pow(w, 5) +
(675675.0/16.0)*std::pow(w, 3) - 45045.0/16.0 * w) * std::sin(3. * phi));
// l = 10, m = -2
rn[i + 8] = 0.012974982402692 * (w2m1)*((2078505.0/128.0)* std::pow(w, 8) -
765765.0/32.0 * std::pow(w, 6) + (675675.0/64.0)* std::pow(w, 4) -
45045.0/32.0 * w * w + 3465.0/128.0) * std::sin(2. * phi);
// l = 10, m = -1
rn[i + 9] = -(0.134839972492648*std::sqrt(w2m1)*((230945.0/128.0)* std::pow(w, 9) -
109395.0/32.0 * std::pow(w, 7) + (135135.0/64.0)* std::pow(w, 5) -
15015.0/32.0 * std::pow(w, 3) + (3465.0/128.0)*w) * std::sin(phi));
// l = 10, m = 0
rn[i + 10] = 180.42578125 * std::pow(w, 10) - 427.32421875 * std::pow(w, 8) +351.9140625
* std::pow(w, 6) - 117.3046875 * std::pow(w, 4) + 13.53515625 * w * w -0.24609375;
// l = 10, m = 1
rn[i + 11] = -(0.134839972492648*std::sqrt(w2m1)*((230945.0/128.0)* std::pow(w, 9) -
109395.0/32.0 * std::pow(w, 7) + (135135.0/64.0)* std::pow(w, 5) -15015.0/
32.0 * std::pow(w, 3) + (3465.0/128.0)*w) * std::cos(phi));
// l = 10, m = 2
rn[i + 12] = 0.012974982402692 * (w2m1)*((2078505.0/128.0)* std::pow(w, 8) -
765765.0/32.0 * std::pow(w, 6) + (675675.0/64.0)* std::pow(w, 4) -
45045.0/32.0 * w * w + 3465.0/128.0) * std::cos(2. * phi);
// l = 10, m = 3
rn[i + 13] = -(0.00127230170115096 * std::pow(w2m1, 1.5)*
((2078505.0/16.0)* std::pow(w, 7) - 2297295.0/16.0 * std::pow(w, 5) +
(675675.0/16.0)*std::pow(w, 3) - 45045.0/16.0 * w) * std::cos(3. * phi));
// l = 10, m = 4
rn[i + 14] = 0.000128521880085575 * w2m1 * w2m1*((14549535.0/16.0)* std::pow(w, 6) -
11486475.0/16.0 * std::pow(w, 4) + (2027025.0/16.0) * w * w -
45045.0/16.0) * std::cos(4.0 * phi);
// l = 10, m = 5
rn[i + 15] = -(1.35473956745817e-5*std::pow(w2m1, 2.5)*
((43648605.0/8.0)* std::pow(w, 5) - 11486475.0/4.0 * std::pow(w, 3) +
(2027025.0/8.0)*w) * std::cos(5.0 * phi));
// l = 10, m = 6
rn[i + 16] = 1.51464488232257e-6*std::pow(w2m1, 3)*((218243025.0/8.0)* std::pow(w, 4) -
34459425.0/4.0 * w * w + 2027025.0/8.0) * std::cos(6.0 * phi);
// l = 10, m = 7
rn[i + 17] = -(1.83677671621093e-7*std::pow(w2m1, 3.5) *
((218243025.0/2.)*std::pow(w, 3) - 34459425.0/2.*w) * std::cos(7.0 * phi));
// l = 10, m = 8
rn[i + 18] = 2.49953651452314e-8*std::pow(w2m1, 4)*
((654729075.0/2.)*w * w - 34459425.0/2.) * std::cos(8.0 * phi);
// l = 10, m = 9
rn[i + 19] = -(2.65478475211798 * w*std::pow(w2m1, 4.5) * std::cos(9.0 * phi));
// l = 10, m = 10
rn[i + 20] = 0.593627917136573 * std::pow(w2m1, 5) * std::cos(10.0 * phi);
}
}
}
void calc_zn_c(int n, double rho, double phi, double zn[]) {
// ===========================================================================
// Determine vector of sin(n*phi) and cos(n*phi). This takes advantage of the
// following recurrence relations so that only a single sin/cos have to be
// evaluated (http://mathworld.wolfram.com/Multiple-AngleFormulas.html)
//
// sin(nx) = 2 cos(x) sin((n-1)x) - sin((n-2)x)
// cos(nx) = 2 cos(x) cos((n-1)x) - cos((n-2)x)
double sin_phi = std::sin(phi);
double cos_phi = std::cos(phi);
double sin_phi_vec[n + 1]; // Sin[n * phi]
double cos_phi_vec[n + 1]; // Cos[n * phi]
sin_phi_vec[0] = 1.0;
cos_phi_vec[0] = 1.0;
sin_phi_vec[1] = 2.0 * cos_phi;
cos_phi_vec[1] = cos_phi;
for (int i = 2; i <= n; i++) {
sin_phi_vec[i] = 2. * cos_phi * sin_phi_vec[i - 1] - sin_phi_vec[i - 2];
cos_phi_vec[i] = 2. * cos_phi * cos_phi_vec[i - 1] - cos_phi_vec[i - 2];
}
for (int i = 0; i <= n; i++) {
sin_phi_vec[i] *= sin_phi;
}
// ===========================================================================
// Calculate R_pq(rho)
double zn_mat[n + 1][n + 1]; // Matrix forms of the coefficients which are
// easier to work with
// Fill the main diagonal first (Eq 3.9 in Chong)
for (int p = 0; p <= n; p++) {
zn_mat[p][p] = std::pow(rho, p);
}
// Fill the 2nd diagonal (Eq 3.10 in Chong)
for (int q = 0; q <= n - 2; q++) {
zn_mat[q][q+2] = (q + 2) * zn_mat[q+2][q+2] - (q + 1) * zn_mat[q][q];
}
// Fill in the rest of the values using the original results (Eq. 3.8 in Chong)
for (int p = 4; p <= n; p++) {
double k2 = 2 * p * (p - 1) * (p - 2);
for (int q = p - 4; q >= 0; q -= 2) {
double k1 = ((p + q) * (p - q) * (p - 2)) / 2.;
double k3 = -q * q * (p - 1) - p * (p - 1) * (p - 2);
double k4 = (-p * (p + q - 2) * (p - q - 2)) / 2.;
zn_mat[q][p] =
((k2 * rho * rho + k3) * zn_mat[q][p-2] + k4 * zn_mat[q][p-4]) / k1;
}
}
// Roll into a single vector for easier computation later
// The vector is ordered (0,0), (1,-1), (1,1), (2,-2), (2,0),
// (2, 2), .... in (n,m) indices
// Note that the cos and sin vectors are offset by one
// sin_phi_vec = [sin(x), sin(2x), sin(3x) ...]
// cos_phi_vec = [1.0, cos(x), cos(2x)... ]
int i = 0;
for (int p = 0; p <= n; p++) {
for (int q = -p; q <= p; q += 2) {
if (q < 0) {
zn[i] = zn_mat[std::abs(q)][p] * sin_phi_vec[std::abs(q) - 1];
} else if (q == 0) {
zn[i] = zn_mat[q][p];
} else {
zn[i] = zn_mat[q][p] * cos_phi_vec[q];
}
i++;
}
}
}
void rotate_angle_c(double uvw[3], double mu, double* phi) {
// Copy original directional cosines
double u0 = uvw[0]; // original cosine in x direction
double v0 = uvw[1]; // original cosine in y direction
double w0 = uvw[2]; // original cosine in z direction
// Sample azimuthal angle in [0,2pi) if none provided
double phi_;
if (phi != nullptr) {
phi_ = (*phi);
} else {
phi_ = 2. * PI * prn();
}
// Precompute factors to save flops
double sinphi = std::sin(phi_);
double cosphi = std::cos(phi_);
double a = std::sqrt(std::fmax(0., 1. - mu * mu));
double b = std::sqrt(std::fmax(0., 1. - w0 * w0));
// Need to treat special case where sqrt(1 - w**2) is close to zero by
// expanding about the v component rather than the w component
if (b > 1e-10) {
uvw[0] = mu * u0 + a * (u0 * w0 * cosphi - v0 * sinphi) / b;
uvw[1] = mu * v0 + a * (v0 * w0 * cosphi + u0 * sinphi) / b;
uvw[2] = mu * w0 - a * b * cosphi;
} else {
b = std::sqrt(1. - v0 * v0);
uvw[0] = mu * u0 + a * (u0 * v0 * cosphi + w0 * sinphi) / b;
uvw[1] = mu * v0 - a * b * cosphi;
uvw[2] = mu * w0 + a * (v0 * w0 * cosphi - u0 * sinphi) / b;
}
}
double maxwell_spectrum_c(double T) {
// Set the random numbers
double r1 = prn();
double r2 = prn();
double r3 = prn();
// determine cosine of pi/2*r
double c = std::cos(PI / 2. * r3);
// Determine outgoing energy
double E_out = -T * (std::log(r1) + std::log(r2) * c * c);
return E_out;
}
double watt_spectrum_c(double a, double b) {
double w = maxwell_spectrum_c(a);
double E_out = w + 0.25 * a * a * b + (2. * prn() - 1.) * std::sqrt(a * a * b * w);
return E_out;
}
void broaden_wmp_polynomials_c(double E, double dopp, int n, double factors[]) {
// Factors is already pre-allocated
double sqrtE = std::sqrt(E);
double beta = sqrtE * dopp;
double half_inv_dopp2 = 0.5 / (dopp * dopp);
double quarter_inv_dopp4 = half_inv_dopp2 * half_inv_dopp2;
double erf_beta; // error function of beta
double exp_m_beta2; // exp(-beta**2)
if (beta > 6.0) {
// Save time, ERF(6) is 1 to machine precision.
// beta/sqrtpi*exp(-beta**2) is also approximately 1 machine epsilon.
erf_beta = 1.;
exp_m_beta2 = 0.;
} else {
erf_beta = std::erf(beta);
exp_m_beta2 = std::exp(-beta * beta);
}
// Assume that, for sure, we'll use a second order (1/E, 1/V, const)
// fit, and no less.
factors[0] = erf_beta / E;
factors[1] = 1. / sqrtE;
factors[2] = factors[0] * (half_inv_dopp2 + E) + exp_m_beta2 /
(beta * SQRT_PI);
// Perform recursive broadening of high order components
for (int i = 0; i < n - 3; i++) {
double ip1_dbl = i + 1;
if (i != 0) {
factors[i + 3] = -factors[i - 1] * (ip1_dbl - 1.) * ip1_dbl *
quarter_inv_dopp4 + factors[i + 1] *
(E + (1. + 2. * ip1_dbl) * half_inv_dopp2);
} else {
// Although it's mathematically identical, factors[0] will contain
// nothing, and we don't want to have to worry about memory.
factors[i + 3] = factors[i + 1] *
(E + (1. + 2. * ip1_dbl) * half_inv_dopp2);
}
}
}
} // namespace openmc

163
src/math_functions.h Normal file
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@ -0,0 +1,163 @@
//! \file math_functions.h
//! A collection of elementary math functions.
#ifndef MATH_FUNCTIONS_H
#define MATH_FUNCTIONS_H
#include <cmath>
#include <cstdlib>
#include "random_lcg.h"
namespace openmc {
//==============================================================================
// Module constants.
//==============================================================================
// TODO: cmath::M_PI has 3 more digits precision than the Fortran constant we
// use so for now we will reuse the Fortran constant until we are OK with
// modifying test results
extern "C" constexpr double PI {3.1415926535898};
extern "C" const double SQRT_PI {std::sqrt(PI)};
//==============================================================================
//! Calculate the percentile of the standard normal distribution with a
//! specified probability level.
//!
//! @param p The probability level
//! @return The requested percentile
//==============================================================================
extern "C" double normal_percentile_c(double p);
//==============================================================================
//! Calculate the percentile of the Student's t distribution with a specified
//! probability level and number of degrees of freedom.
//!
//! @param p The probability level
//! @param df The degrees of freedom
//! @return The requested percentile
//==============================================================================
extern "C" double t_percentile_c(double p, int df);
//==============================================================================
//! Calculate the n-th order Legendre polynomials at the value of x.
//!
//! @param n The maximum order requested
//! @param x The value to evaluate at; x is expected to be within [-1,1]
//! @param pnx The requested Legendre polynomials of order 0 to n (inclusive)
//! evaluated at x.
//==============================================================================
extern "C" void calc_pn_c(int n, double x, double pnx[]);
//==============================================================================
//! Find the value of f(x) given a set of Legendre coefficients and the value
//! of x.
//!
//! @param n The maximum order of the expansion
//! @param data The polynomial expansion coefficient data; without the (2l+1)/2
//! factor.
//! @param x The value to evaluate at; x is expected to be within [-1,1]
//! @return The requested Legendre polynomials of order 0 to n (inclusive)
//! evaluated at x
//==============================================================================
extern "C" double evaluate_legendre_c(int n, const double data[], double x);
//==============================================================================
//! Calculate the n-th order real spherical harmonics for a given angle (in
//! terms of (u,v,w)) for all 0<=n and -m<=n<=n.
//!
//! @param n The maximum order requested
//! @param uvw[3] The direction the harmonics are requested at
//! @param rn The requested harmonics of order 0 to n (inclusive)
//! evaluated at uvw.
//==============================================================================
extern "C" void calc_rn_c(int n, const double uvw[3], double rn[]);
//==============================================================================
//! Calculate the n-th order modified Zernike polynomial moment for a given
//! angle (rho, theta) location on the unit disk.
//!
//! This procedure uses the modified Kintner's method for calculating Zernike
//! polynomials as outlined in Chong, C. W., Raveendran, P., & Mukundan,
//! R. (2003). A comparative analysis of algorithms for fast computation of
//! Zernike moments. Pattern Recognition, 36(3), 731-742.
//! The normalization of the polynomials is such that the integral of Z_pq^2
//! over the unit disk is exactly pi.
//!
//! @param n The maximum order requested
//! @param rho The radial parameter to specify location on the unit disk
//! @param phi The angle parameter to specify location on the unit disk
//! @param zn The requested moments of order 0 to n (inclusive)
//! evaluated at rho and phi.
//==============================================================================
extern "C" void calc_zn_c(int n, double rho, double phi, double zn[]);
//==============================================================================
//! Rotate the direction cosines through a polar angle whose cosine is mu and
//! through an azimuthal angle sampled uniformly.
//!
//! This is done with direct sampling rather than rejection sampling as is done
//! in MCNP and Serpent.
//!
//! @param uvw[3] The initial, and final, direction vector
//! @param mu The cosine of angle in lab or CM
//! @param phi The azimuthal angle; will randomly chosen angle if a nullptr
//! is passed
//==============================================================================
extern "C" void rotate_angle_c(double uvw[3], double mu, double* phi);
//==============================================================================
//! Samples an energy from the Maxwell fission distribution based on a direct
//! sampling scheme.
//!
//! The probability distribution function for a Maxwellian is given as
//! p(x) = 2/(T*sqrt(pi))*sqrt(x/T)*exp(-x/T). This PDF can be sampled using
//! rule C64 in the Monte Carlo Sampler LA-9721-MS.
//!
//! @param T The tabulated function of the incoming energy
//! @result The sampled outgoing energy
//==============================================================================
extern "C" double maxwell_spectrum_c(double T);
//==============================================================================
//! Samples an energy from a Watt energy-dependent fission distribution.
//!
//! Although fitted parameters exist for many nuclides, generally the
//! continuous tabular distributions (LAW 4) should be used in lieu of the Watt
//! spectrum. This direct sampling scheme is an unpublished scheme based on the
//! original Watt spectrum derivation (See F. Brown's MC lectures).
//!
//! @param a Watt parameter a
//! @param b Watt parameter b
//! @result The sampled outgoing energy
//==============================================================================
extern "C" double watt_spectrum_c(double a, double b);
//==============================================================================
//! Doppler broadens the windowed multipole curvefit.
//!
//! The curvefit is a polynomial of the form a/E + b/sqrt(E) + c + d sqrt(E)...
//!
//! @param E The energy to evaluate the broadening at
//! @param dopp sqrt(atomic weight ratio / kT) with kT given in eV
//! @param n The number of components to the polynomial
//! @param factors The output leading coefficient
//==============================================================================
extern "C" void broaden_wmp_polynomials_c(double E, double dopp, int n,
double factors[]);
} // namespace openmc
#endif // MATH_FUNCTIONS_H

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@ -7,7 +7,7 @@ module tally
use dict_header, only: EMPTY
use error, only: fatal_error
use geometry_header
use math, only: t_percentile, calc_pn, calc_rn
use math, only: t_percentile
use mesh_header, only: RegularMesh, meshes
use message_passing
use mgxs_header

View file

@ -51,13 +51,12 @@ contains
type(TallyFilterMatch), intent(inout) :: match
integer :: i
real(8) :: wgt
real(C_DOUBLE) :: wgt(this % n_bins)
! TODO: Use recursive formula to calculate higher orders
do i = 0, this % order
wgt = calc_pn(i, p % mu)
call match % bins % push_back(i + 1)
call match % weights % push_back(wgt)
call calc_pn(this % order, p % mu, wgt)
do i = 1, this % n_bins
call match % bins % push_back(i)
call match % weights % push_back(wgt(i))
end do
end subroutine get_all_bins

View file

@ -74,30 +74,32 @@ contains
integer :: i, j, n
integer :: num_nm
real(8) :: wgt
real(8) :: rn(2*this % order + 1)
real(C_DOUBLE) :: wgt(this % order + 1)
real(C_DOUBLE) :: rn(this % n_bins)
! Determine cosine term for scatter expansion if necessary
if (this % cosine == COSINE_SCATTER) then
call calc_pn(this % order, p % mu, wgt)
else
wgt = ONE
end if
! Find the Rn,m values
call calc_rn(this % order, p % last_uvw, rn)
! TODO: Use recursive formula to calculate higher orders
j = 0
do n = 0, this % order
! Determine cosine term for scatter expansion if necessary
if (this % cosine == COSINE_SCATTER) then
wgt = calc_pn(n, p % mu)
else
wgt = ONE
end if
! Calculate n-th order spherical harmonics for (u,v,w)
num_nm = 2*n + 1
rn(1:num_nm) = calc_rn(n, p % last_uvw)
! Append matching (bin,weight) for each moment
do i = 1, num_nm
j = j + 1
call match % bins % push_back(j)
call match % weights % push_back(wgt * rn(i))
call match % weights % push_back(wgt(n + 1) * rn(j))
end do
end do
end subroutine get_all_bins
subroutine to_statepoint(this, filter_group)

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@ -75,20 +75,19 @@ contains
type(TallyFilterMatch), intent(inout) :: match
integer :: i
real(8) :: wgt
real(8) :: x ! Position on specified axis
real(8) :: x_norm ! Normalized position
real(C_DOUBLE) :: wgt(this % n_bins)
real(C_DOUBLE) :: x ! Position on specified axis
real(C_DOUBLE) :: x_norm ! Normalized position
x = p % coord(1) % xyz(this % axis)
if (this % min <= x .and. x <= this % max) then
! Calculate normalized position between min and max
x_norm = TWO*(x - this % min)/(this % max - this % min) - ONE
! TODO: Use recursive formula to calculate higher orders
do i = 0, this % order
wgt = calc_pn(i, x_norm)
call match % bins % push_back(i + 1)
call match % weights % push_back(wgt)
call calc_pn(this % order, x_norm, wgt)
do i = 1, this % n_bins
call match % bins % push_back(i)
call match % weights % push_back(wgt(i))
end do
end if
end subroutine get_all_bins

View file

@ -61,7 +61,7 @@ contains
integer :: i
real(8) :: x, y, r, theta
real(8) :: zn(this % n_bins)
real(C_DOUBLE) :: zn(this % n_bins)
! Determine normalized (r,theta) positions
x = p % coord(1) % xyz(1) - this % x

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@ -0,0 +1,212 @@
import numpy as np
import scipy as sp
import openmc
import openmc.capi
def test_t_percentile():
# Permutations include 1 DoF, 2 DoF, and > 2 DoF
# We will test 5 p-values at 3-DoF values
test_ps = [0.02, 0.4, 0.5, 0.6, 0.98]
test_dfs = [1, 2, 5]
# The reference solutions come from Scipy
ref_ts = [[sp.stats.t.ppf(p, df) for p in test_ps] for df in test_dfs]
test_ts = [[openmc.capi.math.t_percentile(p, df) for p in test_ps]
for df in test_dfs]
# The 5 DoF approximation in openmc.capi.math.t_percentile is off by up to
# 8e-3 from the scipy solution, so test that one separately with looser
# tolerance
assert np.allclose(ref_ts[:-1], test_ts[:-1])
assert np.allclose(ref_ts[-1], test_ts[-1], atol=1e-2)
def test_calc_pn():
max_order = 10
test_xs = np.linspace(-1., 1., num=5, endpoint=True)
# Reference solutions from scipy
ref_vals = np.array([sp.special.eval_legendre(n, test_xs)
for n in range(0, max_order + 1)])
test_vals = []
for x in test_xs:
test_vals.append(openmc.capi.math.calc_pn(max_order, x).tolist())
test_vals = np.swapaxes(np.array(test_vals), 0, 1)
assert np.allclose(ref_vals, test_vals)
def test_evaluate_legendre():
max_order = 10
# Coefficients are set to 1, but will incorporate the (2l+1)/2 norm factor
# for the reference solution
test_coeffs = [0.5 * (2. * l + 1.) for l in range(max_order + 1)]
test_xs = np.linspace(-1., 1., num=5, endpoint=True)
ref_vals = np.polynomial.legendre.legval(test_xs, test_coeffs)
# Set the coefficients back to 1s for the test values since
# evaluate legendre incorporates the (2l+1)/2 term on its own
test_coeffs = [1. for l in range(max_order + 1)]
test_vals = np.array([openmc.capi.math.evaluate_legendre(test_coeffs, x)
for x in test_xs])
assert np.allclose(ref_vals, test_vals)
def test_calc_rn():
max_order = 10
test_ns = np.array([i for i in range(0, max_order + 1)])
azi = 0.1 # Longitude
pol = 0.2 # Latitude
test_uvw = np.array([np.sin(pol) * np.cos(azi),
np.sin(pol) * np.sin(azi),
np.cos(pol)])
# Reference solutions from the equations
ref_vals = []
def coeff(n, m):
return np.sqrt((2. * n + 1) * sp.special.factorial(n - m) /
(sp.special.factorial(n + m)))
def pnm_bar(n, m, mu):
val = coeff(n, m)
if m != 0:
val *= np.sqrt(2.)
val *= sp.special.lpmv([m], [n], [mu])
return val[0]
ref_vals = []
for n in test_ns:
for m in range(-n, n + 1):
if m < 0:
ylm = pnm_bar(n, np.abs(m), np.cos(pol)) * \
np.sin(np.abs(m) * azi)
else:
ylm = pnm_bar(n, m, np.cos(pol)) * np.cos(m * azi)
# Un-normalize for comparison
ylm /= np.sqrt(2. * n + 1.)
ref_vals.append(ylm)
test_vals = []
test_vals = openmc.capi.math.calc_rn(max_order, test_uvw)
assert np.allclose(ref_vals, test_vals)
def test_calc_zn():
n = 10
rho = 0.5
phi = 0.5
# Reference solution from running the Fortran implementation
ref_vals = np.array([
1.00000000e+00, 2.39712769e-01, 4.38791281e-01,
2.10367746e-01, -5.00000000e-01, 1.35075576e-01,
1.24686873e-01, -2.99640962e-01, -5.48489101e-01,
8.84215021e-03, 5.68310892e-02, -4.20735492e-01,
-1.25000000e-01, -2.70151153e-01, -2.60091773e-02,
1.87022545e-02, -3.42888902e-01, 1.49820481e-01,
2.74244551e-01, -2.43159131e-02, -2.50357380e-02,
2.20500013e-03, -1.98908812e-01, 4.07587508e-01,
4.37500000e-01, 2.61708929e-01, 9.10321205e-02,
-1.54686328e-02, -2.74049397e-03, -7.94845816e-02,
4.75368705e-01, 7.11647284e-02, 1.30266162e-01,
3.37106977e-02, 1.06401886e-01, -7.31606787e-03,
-2.95625975e-03, -1.10250006e-02, 3.55194307e-01,
-1.44627826e-01, -2.89062500e-01, -9.28644588e-02,
-1.62557358e-01, 7.73431638e-02, -2.55329539e-03,
-1.90923851e-03, 1.57578403e-02, 1.72995854e-01,
-3.66267690e-01, -1.81657333e-01, -3.32521518e-01,
-2.59738162e-02, -2.31580576e-01, 4.20673902e-02,
-4.11710546e-04, -9.36449487e-04, 1.92156884e-02,
2.82515641e-02, -3.90713738e-01, -1.69280296e-01,
-8.98437500e-02, -1.08693628e-01, 1.78813094e-01,
-1.98191857e-01, 1.65964201e-02, 2.77013853e-04])
test_vals = openmc.capi.math.calc_zn(n, rho, phi)
assert np.allclose(ref_vals, test_vals)
def test_rotate_angle():
uvw0 = np.array([1., 0., 0.])
phi = 0.
mu = 0.
# reference: mu of 0 pulls the vector the bottom, so:
ref_uvw = np.array([0., 0., -1.])
test_uvw = openmc.capi.math.rotate_angle(uvw0, mu, phi)
assert np.array_equal(ref_uvw, test_uvw)
# Repeat for mu = 1 (no change)
mu = 1.
ref_uvw = np.array([1., 0., 0.])
test_uvw = openmc.capi.math.rotate_angle(uvw0, mu, phi)
assert np.array_equal(ref_uvw, test_uvw)
# Now to test phi is None
mu = 0.9
settings = openmc.capi.settings
settings.seed = 1
# When seed = 1, phi will be sampled as 1.9116495709698769
# The resultant reference is from hand-calculations given the above
ref_uvw = [0.9, 0.410813051297112, 0.1457142302040]
test_uvw = openmc.capi.math.rotate_angle(uvw0, mu)
assert np.allclose(ref_uvw, test_uvw)
def test_maxwell_spectrum():
settings = openmc.capi.settings
settings.seed = 1
T = 0.5
ref_val = 0.6129982175261098
test_val = openmc.capi.math.maxwell_spectrum(T)
assert ref_val == test_val
def test_watt_spectrum():
settings = openmc.capi.settings
settings.seed = 1
a = 0.5
b = 0.75
ref_val = 0.6247242713640233
test_val = openmc.capi.math.watt_spectrum(a, b)
assert ref_val == test_val
def test_broaden_wmp_polynomials():
# Two branches of the code to worry about, beta > 6 and otherwise
# beta = sqrtE * dopp
# First lets do beta > 6
test_E = 0.5
test_dopp = 100. # approximately U235 at room temperature
n = 6
ref_val = [2., 1.41421356, 1.0001, 0.70731891, 0.50030001, 0.353907]
test_val = openmc.capi.math.broaden_wmp_polynomials(test_E, test_dopp, n)
assert np.allclose(ref_val, test_val)
# now beta < 6
test_dopp = 5.
ref_val = [1.99999885, 1.41421356, 1.04, 0.79195959, 0.6224, 0.50346003]
test_val = openmc.capi.math.broaden_wmp_polynomials(test_E, test_dopp, n)
assert np.allclose(ref_val, test_val)