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Update documentation
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Paul Romano
parent
1fc8100034
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2 changed files with 82 additions and 79 deletions
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@ -94,6 +94,18 @@ Settings Specification -- settings.xml
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All simulation parameters and miscellaneous options are specified in the
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settings.xml file.
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``<batches>`` Element
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---------------------
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The ``<batches>`` element indicates the total number of batches to execute,
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where each batch corresponds to a tally realization. In a fixed source
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calculation, each batch consists of a number of source particles. In an
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eigenvalue calculation, each batch consists of one or many fission source
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iterations (generations), where each generation itself consists of a number of
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source neutrons.
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*Default*: None
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``<confidence_intervals>`` Element
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----------------------------------
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@ -132,67 +144,6 @@ you care. This element has the following attributes/sub-elements:
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*Default*: 0.0
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.. _eigenvalue:
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``<eigenvalue>`` Element
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------------------------
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The ``<eigenvalue>`` element indicates that a :math:`k`-eigenvalue calculation
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should be performed. It has the following attributes/sub-elements:
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:batches:
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The total number of batches, where each batch corresponds to multiple
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fission source iterations. Batching is done to eliminate correlation between
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realizations of random variables.
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*Default*: None
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:generations_per_batch:
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The number of total fission source iterations per batch.
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*Default*: 1
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:inactive:
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The number of inactive batches. In general, the starting cycles in a
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criticality calculation can not be used to contribute to tallies since the
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fission source distribution and eigenvalue are generally not converged
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immediately.
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*Default*: None
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:particles:
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The number of neutrons to simulate per fission source iteration.
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*Default*: None
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:keff_trigger:
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This tag specifies a precision trigger on the combined :math:`k_{eff}`. The
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trigger is a convergence criterion on the uncertainty of the estimated
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eigenvalue. It has the following attributes/sub-elements:
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:type:
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The type of precision trigger. Accepted options are "variance", "std_dev",
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and "rel_err".
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:variance:
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Variance of the batch mean :math:`\sigma^2`
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:std_dev:
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Standard deviation of the batch mean :math:`\sigma`
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:rel_err:
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Relative error of the batch mean :math:`\frac{\sigma}{\mu}`
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*Default*: None
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:threshold:
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The precision trigger's convergence criterion for the
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combined :math:`k_{eff}`.
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*Default*: None
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.. note:: See section on the :ref:`trigger` for more information.
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``<energy_grid>`` Element
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-------------------------
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@ -247,23 +198,57 @@ problem. It has the following attributes/sub-elements:
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*Default*: None
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``<fixed_source>`` Element
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``<generations_per_batch>`` Element
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-----------------------------------
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The ``<generations_per_batch>`` element indicates the number of total fission
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source iterations per batch for an eigenvalue calculation. This element is
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ignored for all run modes other than "eigenvalue".
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*Default*: 1
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``<inactive>`` Element
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----------------------
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The ``<inactive>`` element indicates the number of inactive batches used in a
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k-eigenvalue calculation. In general, the starting fission source iterations in
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an eigenvalue calculation can not be used to contribute to tallies since the
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fission source distribution and eigenvalue are generally not converged
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immediately.
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*Default*: 0
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``<keff_trigger>`` Element
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--------------------------
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The ``<fixed_source>`` element indicates that a fixed source calculation should
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be performed. It has the following attributes/sub-elements:
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The ``<keff_trigger>`` element specifies a precision trigger on the combined
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:math:`k_{eff}`. The trigger is a convergence criterion on the uncertainty of
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the estimated eigenvalue. It has the following attributes/sub-elements:
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:batches:
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The total number of batches. For fixed source calculations, each batch
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represents a realization of random variables for tallies.
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:type:
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The type of precision trigger. Accepted options are "variance", "std_dev",
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and "rel_err".
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:variance:
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Variance of the batch mean :math:`\sigma^2`
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:std_dev:
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Standard deviation of the batch mean :math:`\sigma`
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:rel_err:
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Relative error of the batch mean :math:`\frac{\sigma}{\mu}`
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*Default*: None
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:particles:
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The number of particles to simulate per batch.
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:threshold:
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The precision trigger's convergence criterion for the
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combined :math:`k_{eff}`.
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*Default*: None
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.. note:: See section on the :ref:`trigger` for more information.
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``<log_grid_bins>`` Element
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---------------------------
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@ -336,6 +321,15 @@ will abort.
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*Default*: Current working directory
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``<particles>`` Element
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-----------------------
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This element indicates the number of neutrons to simulate per fission source
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iteration when a k-eigenvalue calculation is performed or the number of neutrons
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per batch for a fixed source simulation.
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*Default*: None
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``<ptables>`` Element
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---------------------
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@ -408,7 +402,16 @@ The ``<run_cmfd>`` element indicates whether or not CMFD acceleration should be
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turned on or off. This element has no attributes or sub-elements and can be set
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to either "false" or "true".
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*Defualt*: false
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*Default*: false
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``<run_mode>`` Element
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----------------------
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The ``<run_mode>`` element indicates which run mode should be used when OpenMC
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is executed. This element has no attributes or sub-elements and can be set to
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"eigenvalue", "fixed source", "plot", "volume", or "particle restart".
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*Default*: None
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``<seed>`` Element
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------------------
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@ -774,13 +777,13 @@ number, and particle number, respectively.
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-------------------------
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OpenMC includes tally precision triggers which allow the user to define
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uncertainty thresholds on :math:`k_{eff}` in the ``<eigenvalue>`` subelement of
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``settings.xml``, and/or tallies in ``tallies.xml``. When using triggers,
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uncertainty thresholds on :math:`k_{eff}` in the ``<keff_trigger>`` subelement
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of ``settings.xml``, and/or tallies in ``tallies.xml``. When using triggers,
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OpenMC will run until it completes as many batches as defined by ``<batches>``.
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At this point, the uncertainties on all tallied values are computed and
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compared with their corresponding trigger thresholds. If any triggers have not
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been met, OpenMC will continue until either all trigger thresholds have been
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satisfied or ``<max_batches>`` has been reached.
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At this point, the uncertainties on all tallied values are computed and compared
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with their corresponding trigger thresholds. If any triggers have not been met,
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OpenMC will continue until either all trigger thresholds have been satisfied or
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``<max_batches>`` has been reached.
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The ``<trigger>`` element provides an active "toggle switch" for tally
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precision trigger(s), the maximum number of batches and the batch interval. It
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@ -793,8 +796,8 @@ has the following attributes/sub-elements:
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:max_batches:
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This describes the maximum number of batches allowed when using trigger(s).
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.. note:: When max_batches is set, the number of ``batches`` shown in
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``<eigenvalue>`` element represents minimum number of batches to
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.. note:: When max_batches is set, the number of ``batches`` shown in the
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``<batches>`` element represents minimum number of batches to
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simulate when using the trigger(s).
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:batch_interval:
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