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Move custom source description to user's guide

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Paul Romano 2020-04-13 07:22:57 -05:00
parent 5547ecf88f
commit b73f07655b
2 changed files with 60 additions and 61 deletions
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61
docs/source/io_formats/settings.rst
View file

@ -600,67 +600,6 @@ attributes/sub-elements:
*Default*: false
.. _custom_source:
Custom Sources
++++++++++++++
It is often the case that one may wish to simulate a complex source
distribution, which may include physics not present within OpenMC or to be phase
space complex. It is possible to define a complex source with an externally
defined source function that is loaded at runtime. A simple example source is
shown below.
.. code-block:: c++
#include "openmc/random_lcg.h"
#include "openmc/source.h"
#include "openmc/particle.h"
// you must have external C linkage here
extern "C" openmc::Particle::Bank sample_source(uint64_t* seed) {
openmc::Particle::Bank particle;
// weight
particle.particle = openmc::Particle::Type::neutron;
particle.wgt = 1.0;
// position
double angle = 2.0 * M_PI * openmc::prn(seed);
double radius = 3.0;
particle.r.x = radius * std::cos(angle);
particle.r.y = radius * std::sin(angle);
particle.r.z = 0.0;
// angle
particle.u = {1.0, 0.0, 0.0};
particle.E = 14.08e6;
particle.delayed_group = 0;
return particle;
}
The above source, creates 14.08 MeV neutrons, with an istropic direction
vector but distributed in a ring with a 3 cm radius. This routine is
not particularly complex, but should serve as an example upon which to build
more complicated sources.
.. note:: The function signature must be declared to be extern "C".
.. note:: You should only use the openmc::prn() random number generator
In order to build your external source, you will need to link it against the
OpenMC shared library. This can be done by writing a CMakeLists.txt file:
.. code-block:: cmake
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(openmc_sources CXX)
add_library(source SHARED source_ring.cpp)
find_package(OpenMC REQUIRED HINTS <path to openmc>)
target_link_libraries(source OpenMC::libopenmc)
After running ``cmake`` and ``make``, you will have a libsource.so (or .dylib)
file in your build directory. Setting the :attr:`openmc.Source.library`
attribute to the path of this shared library will indicate that it should be
used for sampling source particles at runtime.
.. _univariate:
Univariate Probability Distributions

60
docs/source/usersguide/settings.rst
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@ -164,6 +164,66 @@ following would generate a photon source::
For a full list of all classes related to statistical distributions, see
:ref:`pythonapi_stats`.
.. _custom_source:
Custom Sources
--------------
It is often the case that one may wish to simulate a complex source distribution
that is not possible to represent with the classes described above. For these
situations, it is possible to define a complex source with an externally defined
source function that is loaded at runtime. A simple example source is shown
below.
.. code-block:: c++
#include "openmc/random_lcg.h"
#include "openmc/source.h"
#include "openmc/particle.h"
// you must have external C linkage here
extern "C" openmc::Particle::Bank sample_source(uint64_t* seed) {
openmc::Particle::Bank particle;
// weight
particle.particle = openmc::Particle::Type::neutron;
particle.wgt = 1.0;
// position
double angle = 2.0 * M_PI * openmc::prn(seed);
double radius = 3.0;
particle.r.x = radius * std::cos(angle);
particle.r.y = radius * std::sin(angle);
particle.r.z = 0.0;
// angle
particle.u = {1.0, 0.0, 0.0};
particle.E = 14.08e6;
particle.delayed_group = 0;
return particle;
}
The above source creates monodirectional 14.08 MeV neutrons that are distributed
in a ring with a 3 cm radius. This routine is not particularly complex, but
should serve as an example upon which to build more complicated sources.
.. note:: The function signature must be declared ``extern "C"``.
.. note:: You should only use the openmc::prn() random number generator
In order to build your external source, you will need to link it against the
OpenMC shared library. This can be done by writing a CMakeLists.txt file:
.. code-block:: cmake
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(openmc_sources CXX)
add_library(source SHARED source_ring.cpp)
find_package(OpenMC REQUIRED HINTS <path to openmc>)
target_link_libraries(source OpenMC::libopenmc)
After running ``cmake`` and ``make``, you will have a libsource.so (or .dylib)
file in your build directory. Setting the :attr:`openmc.Source.library`
attribute to the path of this shared library will indicate that it should be
used for sampling source particles at runtime.
---------------
Shannon Entropy
---------------