mirror of
https://github.com/openmc-dev/openmc.git
synced 2026-07-28 06:05:58 -04:00
adding back files to be reviewed
This commit is contained in:
Paul Romano
parent
ae28233110
commit
bc09d1ef55
1244 changed files with 301904 additions and 0 deletions
190
docs/source/usersguide/basics.rst
Normal file
190
docs/source/usersguide/basics.rst
Normal file
|
|
@ -0,0 +1,190 @@
|
|||
.. _usersguide_basics:
|
||||
|
||||
======================
|
||||
Basics of Using OpenMC
|
||||
======================
|
||||
|
||||
----------------
|
||||
Creating a Model
|
||||
----------------
|
||||
|
||||
When you build and install OpenMC, you will have an :ref:`scripts_openmc`
|
||||
executable on your system. When you run ``openmc``, the first thing it will do
|
||||
is look for a set of XML_ files that describe the model you want to
|
||||
simulation. Three of these files are required and another three are optional, as
|
||||
described below.
|
||||
|
||||
.. admonition:: Required
|
||||
:class: error
|
||||
|
||||
:ref:`io_materials`
|
||||
This file describes what materials are present in the problem and what they
|
||||
are composed of. Additionally, it indicates where OpenMC should look for a
|
||||
cross section library.
|
||||
|
||||
:ref:`io_geometry`
|
||||
This file describes how the materials defined in ``materials.xml`` occupy
|
||||
regions of space. Physical volumes are defined using constructive solid
|
||||
geometry, described in detail in :ref:`usersguide_geometry`.
|
||||
|
||||
:ref:`io_settings`
|
||||
This file indicates what mode OpenMC should be run in, how many particles
|
||||
to simulate, the source definition, and a whole host of miscellaneous
|
||||
options.
|
||||
|
||||
.. admonition:: Optional
|
||||
:class: note
|
||||
|
||||
:ref:`io_tallies`
|
||||
This file describes what physical quantities should be tallied during the
|
||||
simulation (fluxes, reaction rates, currents, etc.).
|
||||
|
||||
:ref:`io_plots`
|
||||
This file gives specifications for producing slice or voxel plots of the
|
||||
geometry.
|
||||
|
||||
eXtensible Markup Language (XML)
|
||||
--------------------------------
|
||||
|
||||
Unlike many other Monte Carlo codes which use an arbitrary-format ASCII file
|
||||
with "cards" to specify a particular geometry, materials, and associated run
|
||||
settings, the input files for OpenMC are structured in a set of `XML
|
||||
<http://www.w3.org/XML/>`_ files. XML, which stands for eXtensible Markup
|
||||
Language, is a simple format that allows data to be exchanged efficiently
|
||||
between different programs and interfaces.
|
||||
|
||||
Anyone who has ever seen webpages written in HTML will be familiar with the
|
||||
structure of XML whereby "tags" enclosed in angle brackets denote that a
|
||||
particular piece of data will follow. Let us examine the follow example:
|
||||
|
||||
.. code-block:: xml
|
||||
|
||||
<person>
|
||||
<firstname>John</firstname>
|
||||
<lastname>Smith</lastname>
|
||||
<age>27</age>
|
||||
<occupation>Health Physicist</occupation>
|
||||
</person>
|
||||
|
||||
Here we see that the first tag indicates that the following data will describe a
|
||||
person. The nested tags *firstname*, *lastname*, *age*, and *occupation*
|
||||
indicate characteristics about the person being described.
|
||||
|
||||
In much the same way, OpenMC input uses XML tags to describe the geometry, the
|
||||
materials, and settings for a Monte Carlo simulation. Note that because the XML
|
||||
files have a well-defined structure, they can be validated using the
|
||||
:ref:`scripts_validate` script or using :ref:`Emacs nXML mode
|
||||
<usersguide_nxml>`.
|
||||
|
||||
Creating Input Files
|
||||
--------------------
|
||||
|
||||
.. currentmodule:: openmc
|
||||
|
||||
The most rudimentary option for creating input files is to simply write them
|
||||
from scratch using the :ref:`XML format specifications
|
||||
<io_file_formats_input>`. This approach will feel familiar to users of other
|
||||
Monte Carlo codes such as MCNP and Serpent, with the added bonus that the XML
|
||||
formats feel much more "readable". Alternatively, input files can be generated
|
||||
using OpenMC's :ref:`Python API <pythonapi>`, which is introduced in the
|
||||
following section.
|
||||
|
||||
----------
|
||||
Python API
|
||||
----------
|
||||
|
||||
OpenMC's :ref:`Python API <pythonapi>` defines a set of functions and classes
|
||||
that roughly correspond to elements in the XML files. For example, the
|
||||
:class:`openmc.Cell` Python class directly corresponds to the
|
||||
:ref:`cell_element` in XML. Each XML file itself also has a corresponding class:
|
||||
:class:`openmc.Geometry` for ``geometry.xml``, :class:`openmc.Materials` for
|
||||
``materials.xml``, :class:`openmc.Settings` for ``settings.xml``, and so on. To
|
||||
create a model then, one creates instances of these classes and then uses the
|
||||
``export_to_xml()`` method, e.g., :meth:`Geometry.export_to_xml`. Most scripts
|
||||
that generate a full model will look something like the following:
|
||||
|
||||
.. code-block:: Python
|
||||
|
||||
# Create materials
|
||||
materials = openmc.Materials()
|
||||
...
|
||||
materials.export_to_xml()
|
||||
|
||||
# Create geometry
|
||||
geometry = openmc.Geometry()
|
||||
...
|
||||
geometry.export_to_xml()
|
||||
|
||||
# Assign simulation settings
|
||||
settings = openmc.Settings()
|
||||
...
|
||||
settings.export_to_xml()
|
||||
|
||||
Once a model has been created and exported to XML, a simulation can be run either
|
||||
by calling :ref:`scripts_openmc` directly from a shell or by using the
|
||||
:func:`openmc.run()` function from Python.
|
||||
|
||||
Identifying Objects
|
||||
-------------------
|
||||
|
||||
In the XML user input files, each object (cell, surface, tally, etc.) has to be
|
||||
uniquely identified by a positive integer (ID) in the same manner as MCNP and
|
||||
Serpent. In the Python API, integer IDs can be assigned but it is not strictly
|
||||
required. When IDs are not explicitly assigned to instances of the OpenMC Python
|
||||
classes, they will be automatically assigned.
|
||||
|
||||
.. _result_files:
|
||||
|
||||
-----------------------------
|
||||
Viewing and Analyzing Results
|
||||
-----------------------------
|
||||
|
||||
After a simulation has been completed by running :ref:`scripts_openmc`, you will
|
||||
have several output files that were created:
|
||||
|
||||
``tallies.out``
|
||||
An ASCII file showing the mean and standard deviation of the mean for any
|
||||
user-defined tallies.
|
||||
|
||||
``summary.h5``
|
||||
An HDF5 file with a complete description of the geometry and materials used in
|
||||
the simulation.
|
||||
|
||||
``statepoint.#.h5``
|
||||
An HDF5 file with the complete results of the simulation, including tallies as
|
||||
well as the final source distribution. This file can be used both to
|
||||
view/analyze results as well as restart a simulation if desired.
|
||||
|
||||
For a simple simulation with few tallies, looking at the ``tallies.out`` file
|
||||
might be sufficient. For anything more complicated (plotting results, finding a
|
||||
subset of results, etc.), you will likely find it easier to work with the
|
||||
statepoint file directly using the :class:`openmc.StatePoint` class. For more
|
||||
details on working with statepoints, see :ref:`usersguide_statepoint`.
|
||||
|
||||
--------------
|
||||
Physical Units
|
||||
--------------
|
||||
|
||||
Unless specified otherwise, all length quantities are assumed to be in units of
|
||||
centimeters, all energy quantities are assumed to be in electronvolts, and all
|
||||
time quantities are assumed to be in seconds.
|
||||
|
||||
======= ============ ======
|
||||
Measure Default unit Symbol
|
||||
======= ============ ======
|
||||
length centimeter cm
|
||||
energy electronvolt eV
|
||||
time second s
|
||||
======= ============ ======
|
||||
|
||||
------------------------------------
|
||||
ERSN-OpenMC Graphical User Interface
|
||||
------------------------------------
|
||||
|
||||
A third-party Java-based user-friendly graphical user interface for creating XML
|
||||
input files called ERSN-OpenMC_ is developed and maintained by members of the
|
||||
Radiation and Nuclear Systems Group at the Faculty of Sciences Tetouan, Morocco.
|
||||
The GUI also allows one to automatically download prerequisites for installing and
|
||||
running OpenMC.
|
||||
|
||||
.. _ERSN-OpenMC: https://github.com/EL-Bakkali-Jaafar/ERSN-OpenMC
|
||||
Loading…
Add table
Add a link
Reference in a new issue