# 1. State Point File Format¶

The current version of the statepoint file format is 18.1.

**/**

- Attributes
**filetype**(*char[]*) – String indicating the type of file.**version**(*int[2]*) – Major and minor version of the statepoint file format.**openmc_version**(*int[3]*) – Major, minor, and release version number for OpenMC.**git_sha1**(*char[40]*) – Git commit SHA-1 hash.**date_and_time**(*char[]*) – Date and time the summary was written.**path**(*char[]*) – Path to directory containing input files.**tallies_present**(*int*) – Flag indicating whether tallies are present (1) or not (0).**source_present**(*int*) – Flag indicating whether the source bank is present (1) or not (0).

- Datasets
**seed**(*int8_t*) – Pseudo-random number generator seed.**energy_mode**(*char[]*) – Energy mode of the run, either ‘continuous-energy’ or ‘multi-group’.**run_mode**(*char[]*) – Run mode used, either ‘eigenvalue’ or ‘fixed source’.**n_particles**(*int8_t*) – Number of particles used per generation.**n_batches**(*int*) – Number of batches to simulate.**current_batch**(*int*) – The number of batches already simulated.**n_inactive**(*int*) – Number of inactive batches. Only present when run_mode is ‘eigenvalue’.**generations_per_batch**(*int*) – Number of generations per batch. Only present when run_mode is ‘eigenvalue’.**k_generation**(*double[]*) – k-effective for each generation simulated.**entropy**(*double[]*) – Shannon entropy for each generation simulated.**k_col_abs**(*double*) – Sum of product of collision/absorption estimates of k-effective.**k_col_tra**(*double*) – Sum of product of collision/track-length estimates of k-effective.**k_abs_tra**(*double*) – Sum of product of absorption/track-length estimates of k-effective.**k_combined**(*double[2]*) – Mean and standard deviation of a combined estimate of k-effective.**n_realizations**(*int*) – Number of realizations for global tallies.**global_tallies**(*double[][2]*) – Accumulated sum and sum-of-squares for each global tally.**source_bank**(Compound type) – Source bank information for each particle. The compound type has fields`r`

,`u`

,`E`

,`time`

,`wgt`

,`delayed_group`

,`surf_id`

, and`particle`

, which represent the position, direction, energy, time, weight, delayed group, surface ID, and particle type (0=neutron, 1=photon, 2=electron, 3=positron), respectively. Only present when run_mode is ‘eigenvalue’.

**/tallies/**

- Attributes
**n_tallies**(*int*) – Number of user-defined tallies.**ids**(*int[]*) – User-defined unique ID of each tally.

**/tallies/meshes/**

- Attributes
**n_meshes**(*int*) – Number of meshes in the problem.**ids**(*int[]*) – User-defined unique ID of each mesh.

**/tallies/meshes/mesh <uid>/**

- Datasets
**type**(*char[]*) – Type of mesh.**dimension**(*int*) – Number of mesh cells in each dimension.**Regular Mesh Only:****lower_left**(*double[]*) – Coordinates of lower-left corner of mesh.**upper_right**(*double[]*) – Coordinates of upper-right corner of mesh.**width**(*double[]*) – Width of each mesh cell in each dimension.

**Rectilinear Mesh Only:****x_grid**(*double[]*) – Mesh divisions along the x-axis.**y_grid**(*double[]*) – Mesh divisions along the y-axis.**z_grid**(*double[]*) – Mesh divisions along the z-axis.

**Cylindrical & Spherical Mesh Only:****r_grid**(*double[]*) – The mesh divisions along the r-axis.**phi_grid**(*double[]*) – The mesh divisions along the phi-axis.**origin**(*double[]*) – The origin in cartesian coordinates.

**Spherical Mesh Only:****theta_grid**(*double[]*) – The mesh divisions along the theta-axis.

**Unstructured Mesh Only:****filename**(*char[]*) – Name of the mesh file.**library**(*char[]*) – Mesh library used to represent themesh (“moab” or “libmesh”).

**length_multiplier**(*double*) Scaling factor applied to the mesh.**volumes**(*double[]*) – Volume of each mesh cell.**vertices**(*double[]*) – x, y, z values of the mesh vertices.**connectivity**(*int[]*) – Connectivity array for the mesh cells.**element_types**(*int[]*) – Mesh element types.

**/tallies/filters/**

- Attributes
**n_filters**(*int*) – Number of filters in the problem.**ids**(*int[]*) – User-defined unique ID of each filter.

**/tallies/filters/filter <uid>/**

- Datasets
**type**(*char[]*) – Type of the j-th filter. Can be ‘universe’, ‘material’, ‘cell’, ‘cellborn’, ‘surface’, ‘mesh’, ‘energy’, ‘energyout’, ‘distribcell’, ‘mu’, ‘polar’, ‘azimuthal’, ‘delayedgroup’, or ‘energyfunction’.**n_bins**(*int*) – Number of bins for the j-th filter. Not present for ‘energyfunction’ filters.**bins**(*int[]*or*double[]*) – Value for each filter bin of this type. Not present for ‘energyfunction’ filters.**energy**(*double[]*) – Energy grid points for energyfunction interpolation. Only used for ‘energyfunction’ filters.**y**(*double[]*) – Interpolant values for energyfunction interpolation. Only used for ‘energyfunction’ filters.- Attributes
**interpolation**(*int*) – Interpolation type. Only used for ‘energyfunction’ filters.

**/tallies/derivatives/derivative <id>/**

- Datasets
**independent variable**(*char[]*) – Independent variable of tally derivative.**material**(*int*) – ID of the perturbed material.**nuclide**(*char[]*) – Alias of the perturbed nuclide.**estimator**(*char[]*) – Type of tally estimator, either ‘analog’, ‘tracklength’, or ‘collision’.

**/tallies/tally <uid>/**

- Attributes
**internal**(*int*) – Flag indicating the presence of tally data (0) or absence of tally data (1). All user defined tallies will have a value of 0 unless otherwise instructed.**multiply_density**(*int*) – Flag indicating whether reaction rates should be multiplied by atom density (1) or not (0).

- Datasets
**n_realizations**(*int*) – Number of realizations.**n_filters**(*int*) – Number of filters used.**filters**(*int[]*) – User-defined unique IDs of the filters on the tally**nuclides**(*char[][]*) – Array of nuclides to tally. Note that if no nuclide is specified in the user input, a single ‘total’ nuclide appears here.**derivative**(*int*) – ID of the derivative applied to the tally.**n_score_bins**(*int*) – Number of scoring bins for a single nuclide.**score_bins**(*char[][]*) – Values of specified scores.**results**(*double[][][2]*) – Accumulated sum and sum-of-squares for each bin of the i-th tally. The first dimension represents combinations of filter bins, the second dimensions represents scoring bins, and the third dimension has two entries for the sum and the sum-of-squares.

**/runtime/**

All values are given in seconds and are measured on the master process.

- Datasets
**total initialization**(*double*) – Time spent reading inputs, allocating arrays, etc.**reading cross sections**(*double*) – Time spent loading cross section libraries (this is a subset of initialization).**simulation**(*double*) – Time spent between initialization and finalization.**transport**(*double*) – Time spent transporting particles.**inactive batches**(*double*) – Time spent in the inactive batches (including non-transport activities like communicating sites).**active batches**(*double*) – Time spent in the active batches (including non-transport activities like communicating sites).**synchronizing fission bank**(*double*) – Time spent sampling source particles from fission sites and communicating them to other processes for load balancing.**sampling source sites**(*double*) – Time spent sampling source particles from fission sites.**SEND-RECV source sites**(*double*) – Time spent communicating source sites between processes for load balancing.**accumulating tallies**(*double*) – Time spent communicating tally results and evaluating their statistics.**writing statepoints**(*double*) – Time spent writing statepoint files