From 80ecd2406ba6a2c6cef901e9a1c8a5db69b7456f Mon Sep 17 00:00:00 2001
From: Adam Nelson <nelsonag@umich.edu>
Date: Mon, 6 Jun 2016 05:19:56 -0400
Subject: [PATCH] Repeated the more analytic integration in the conversion of
 Legendre to Tabular data

---
 src/mgxs_header.F90      | 14 +++++++++++++-
 src/scattdata_header.F90 |  1 -
 src/tally.F90            |  2 --
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/mgxs_header.F90 b/src/mgxs_header.F90
index 750a8df98..fd909ca00 100644
--- a/src/mgxs_header.F90
+++ b/src/mgxs_header.F90
@@ -277,7 +277,7 @@ module mgxs_header
       real(8), allocatable    :: scatt_coeffs(:, :, :)
       real(8), allocatable    :: input_scatt(:, :, :)
       real(8), allocatable    :: temp_scatt(:, :, :)
-      real(8)                 :: dmu, mu, norm
+      real(8)                 :: dmu, mu, norm, p0, m, mu0
       integer                 :: order, order_dim, gin, gout, l, arr_len
       integer                 :: legendre_mu_points, imu
 
@@ -496,6 +496,18 @@ module mgxs_header
                        (scatt_coeffs(imu - 1, gout, gin) + &
                         scatt_coeffs(imu, gout, gin))
                 end if
+                ! Now create CDF from fmu with the analytical integral of a
+                ! piecewise linear function
+                if (imu > 1) then
+                  p0 = scatt_coeffs(imu - 1, gout, gin)
+                  mu0 = mu - dmu
+                  m = (scatt_coeffs(imu, gout, gin) - &
+                       scatt_coeffs(imu - 1, gout, gin)) / dmu
+                  norm = norm + &
+                       HALF * m * mu * mu + &
+                       (p0 - m * mu0) * mu + &
+                       (HALF * m * mu0 * mu0 - p0 * mu0)
+                end if
               end do
               ! Now that we have the integral, lets ensure that the distribution
               ! is normalized such that it preserves the original scattering xs
diff --git a/src/scattdata_header.F90 b/src/scattdata_header.F90
index 06e052eec..6fca89190 100644
--- a/src/scattdata_header.F90
+++ b/src/scattdata_header.F90
@@ -420,7 +420,6 @@ contains
             this % dist(gin) % data(imu, gout) = HALF * m * mu1 * mu1 + &
                  (p0 - m * mu0) * mu1 + &
                  (HALF * m * mu0 * mu0 - p0 * mu0)
-
           end do
           ! Ensure we normalize to 1 still
           norm = this % dist(gin) % data(order, gout)
diff --git a/src/tally.F90 b/src/tally.F90
index 0c41b6f98..b40a39ce0 100644
--- a/src/tally.F90
+++ b/src/tally.F90
@@ -107,8 +107,6 @@ contains
     real(8) :: atom_density_        ! atom/b-cm
     real(8) :: f                    ! interpolation factor
     real(8) :: score                ! analog tally score
-    real(8) :: macro_total          ! material macro total xs
-    real(8) :: macro_scatt          ! material macro scatt xs
     real(8) :: E                    ! particle energy
 
     i = 0