I/O Parameters

General

There are three ways to specify the frequency of outputs: time-based, cycle-based (a cycle is a top-grid timestep), and, for cosmology simulations, redshift-based. There is also a shortened output format intended for visualization (movie format). Please have a look at Controlling Enzo Data Output for more information.

dtDataDump (external)
The time interval, in code units, between time-based outputs. A value of 0 turns off the time-based outputs. Default: 0
dtInterpolatedDataDump (external)
The time interval, in code units, between time-based interpolated outputs. A value of 0 turns off the time-based outputs. Default: 0
CycleSkipDataDump (external)
The number of cycles (top grid timesteps) between cycle-based outputs. Zero turns off the cycle-based outputs. Default: 0
SubcycleSkipDataDump (external)
The number of subcycles between subcycle-based outputs. Zero turns off the subcycle-based outputs. Default: 0
dtTracerParticleDump (external)
The time interval, in code units, between time-based tracer particle outputs (defined in ComputeRandomForcingNormalization.C). A value of 0 turns off this output. Default: 0
DataDumpName (external)
The base file name used for both time and cycle based outputs. Default: data
RedshiftDumpName (external)
The base file name used for redshift-based outputs (this can be overridden by the CosmologyOutputRedshiftName parameter). Normally a four digit identification number is appended to the end of this name, starting from 0000 and incrementing by one for every output. This can be over-ridden by including four consecutive R’s in the name (e.g. RedshiftRRRR) in which case the an identification number will not be appended but the four R’s will be converted to a redshift with an implied decimal point in the middle (i.e. z=1.24 becomes 0124). Default: RedshiftOutput
TracerParticleDumpName (external)
The base file name used for tracer particle outputs. Default:
TracerParticleDumpDir (external)
The dir name used for tracer particle outputs. Default:
dtRestartDump
Reserved for future use.
dtHistoryDump
Reserved for future use.
CycleSkipRestartDump
Reserved for future use.
CycleSkipHistoryDump
Reserved for future use.
RestartDumpName
Reserved for future use.
HistoryDumpName
Reserved for future use.
CosmologyOutputRedshift[NNNN] (external)
The time and cycle-based outputs occur regularly at constant intervals, but the redshift outputs are specified individually. This is done by the use of this statement, which sets the output redshift for a specific identification number (this integer is between 0000 and 9999 and is used in forming the name). So the statement CosmologyOutputRedshift[1] = 4.0 will cause an output to be written out at z=4 with the name RedshiftOutput0001 (unless the base name is changed either with the previous parameter or the next one). This parameter can be repeated with different values for the number (NNNN) Default: none
CosmologyOutputRedshiftName[NNNN] (external)
This parameter overrides the parameter RedshiftOutputName for this (only only this) redshift output. Can be used repeatedly in the same manner as the previous parameter. Default: none
FileDirectedOutput
If this parameter is set to 1, whenever the finest level has finished evolving Enzo will check for new signal files to output. (See Force Output Now.) Default 1.
TracerParticleOn
This parameter is used to set the velocities of the tracer particles equal to the gas velocities in the current cells. Tracer particles are massless and can be used to output values of the gas as they advect with the fluid. Default: 0
TracerParticleOutputVelocity
This parameter is used to output tracer particle velocity as well as position, density, and temperature. Default: 0
OutputFirstTimeAtLevel (external)
This forces Enzo to output when a given level is reached, and at every level thereafter. Default is 0 (off). User can usefully specify anything up to the maximum number of levels in a given simulation.
ParallelRootGridIO (external)
Normally for the mpi version, the root grid is read into the root processor and then partitioned to separate processors using communication. However, for very large root grids (e.g. 5123), the root processor may not have enough memory. If this toggle switch is set on (i.e. to the value 1), then each processor reads its own section of the root grid. More I/O is required (to split up the grids and particles), but it is more balanced in terms of memory. ParallelRootGridIO and ParallelParticleIO MUST be set to 1 (TRUE) for runs involving > 64 cpus! Default: 0 (FALSE). See ParallelParticleIO in Particle Parameters. See also Unigrid in Initialization Parameters.
OutputTemperature (external)
Set to 1 if you want to output a temperature field in the datasets. Always 1 for cosmology simulations. Default: 0.
OutputCoolingTime (external)
Set to 1 if you want to output the cooling time in the datasets. Default: 0.
OutputSmoothedDarkMatter (external)
Set to 1 if you want to output a dark matter density field, smoothed by an SPH kernel. Set to 2 to also output smoothed dark matter velocities and velocity dispersion. Set to 0 to turn off. Default: 0.
SmoothedDarkMatterNeighbors (external)
Number of nearest neighbors to smooth dark matter quantities over. Default: 32.
OutputGriddedStarParticle (external)
Set to 1 or 2 to write out star particle data gridded onto mesh. This will be useful e.g. if you have lots of star particles in a galactic scale simulation. 1 will output just star_particle_density; and 2 will dump actively_forming_stellar_mass_density, SFR_density, etc. Default: 0.
PopIIIOutputOnFeedback (external)
Writes an interpolated output when a Pop III is formed or goes supernova. Default: 0
OutputOnDensity (external)
Should interpolated outputs be generated at varying peak density? Default: 0
StartDensityOutput (external)
The first density (in log g/cc) at which to output.
CurrentDensityOutput (internal)
The most recent density at which output was generated.
IncrementDensityOutput (external)
After a density-directed output, how much should the density be increased by? Default: 999
ComputePotential (external)
When turned on, the gravitational potential is computed and stored in memory. Always done when SelfGravity is on. Default: 0
WritePotential (external)
When turned on, the gravitational potential is written to file. Default: 0
WriteGhostZones (external)
Should ghost zones be written to disk? Default: 0
ReadGhostZones (external)
Are ghost zones present in the files on disk? Default: 0
VelAnyl (external)
Set to 1 if you want to output the divergence and vorticity of velocity. Works in 2D and 3D.
BAnyl (external)
Set to 1 if you want to output the divergence and vorticity of Bfield. Works in 2D and 3D.
ExtractFieldsOnly (external)
Used for extractions (enzo -x ...) when only field data are needed instead of field + particle data. Default is 1 (TRUE).
XrayLowerCutoffkeV, XrayUpperCutoffkeV, XrayTableFileName (external)
These parameters are used in 2D projections (enzo -p ...). The first two specify the X-ray band (observed at z=0) to be used, and the last gives the name of an ascii file that contains the X-ray spectral information. A gzipped version of this file good for bands within the 0.1 - 20 keV range is provided in the distribution in input/lookup_metal0.3.data. If these parameters are specified, then the second field is replaced with integrated emissivity along the line of sight in units of 10-23 erg/cm2/s. Default: XrayLowerCutoffkeV = 0.5, XrayUpperCutoffkeV = 2.5.
ParticleTypeInFile (external)
Output ParticleType to disk? Default: 1
OutputParticleTypeGrouping (external)
In the grid HDF5 groups, particles are sorted by type, and a reference is created to indicate which particle index range corresponds to each type. Default: 0
HierarchyFileInputFormat (external)
See Controlling the Hierarchy File Output Format.
HierarchyFileOutputFormat (external)
See Controlling the Hierarchy File Output Format.
TimingCycleSkip (external)
Controls how many cycles to skip when timing information is collected, reduced, and written out to performance.out. Default: 1
DatabaseLocation (external)
(Not recommended for use at this point) Where should the SQLite database of outputs be placed?
CubeDumpEnabled (external)
not recommended for use at this point. Default: 0
CubeDump[] (external)
not recommended for use at this point
LocalDir (external)
See Controlling Enzo Data Output.
GlobalDir (external)
See Controlling Enzo Data Output.

Stopping Parameters

StopTime (external)
This parameter specifies the time (in code units) when the calculation will halt. For cosmology simulations, this variable is automatically set by CosmologyFinalRedshift. No default.
StopCycle (external)
The cycle (top grid timestep) at which the calculation stops. A value of zero indicates that this criterion is not be used. Default: 100,000
StopFirstTimeAtLevel (external)
Causes the simulation to immediately stop when a specified level is reached. Default value 0 (off), possible values are levels 1 through maximum number of levels in a given simulation.
StopFirstTimeAtDensity (external)
Causes the simulation to immediately stop when the maximum gas density reaches this value. In units of proper g/cm^3. Not used if less than or equal to zero. Default: 0.0
StopFirstTimeAtMetalEnrichedDensity (external)
Causes the simulation to immediately stop when the maximum gas density with above some metallicity, specified by EnrichedMetalFraction, is reached. In units of g/cm^3. Not used if less than or equal to zero. Default: 0.0
EnrichedMetalFraction (external)
See StopFirstTimeAtMetalEnrichedDensity. In units of absolute metal fraction. Default: 1e-8
NumberOfOutputsBeforeExit (external)
After this many datadumps have been written, the code will exit. If set to 0 (default), this option will not be used. Default: 0.
StopCPUTime (external)
Causes the simulation to stop if the wall time exceeds StopCPUTime. The simulation will output if the wall time after the next top-level timestep will exceed StopCPUTime, assuming that the wall time elapsed during a top-level timestep the same as the previous timestep. In units of seconds. Default: 2.592e6 (30 days)
ResubmitOn (external)
If set to 1, the simulation will stop if the wall time will exceed StopCPUTime within the next top-level timestep and run a shell script defined in ResubmitCommand that should resubmit the job for the user. Default: 0.
ResubmitCommand (external)
Filename of a shell script that creates a queuing (e.g. PBS) script from two arguments, the number of processors and parameter file. This script is run by the root processor when stopping with ResubmitOn. An example script can be found in input/resubmit.sh. Default: (null)

Streaming Data Format

NewMovieLeftEdge, NewMovieRightEdge (external)
These two parameters control the region for which the streaming data are written. Default: DomainLeftEdge and DomainRightEdge.
MovieSkipTimestep (external)
Controls how many timesteps on a level are skipped between outputs in the streaming data. Streaming format is off if this equals INT_UNDEFINED. Default: INT_UNDEFINED
Movie3DVolume (external)
Set to 1 to write streaming data as 3-D arrays. This should always be set to 1 if using the streaming format. A previous version had 2D maximum intensity projections, which now defunct. Default: 0.
MovieVertexCentered (external)
Set to 1 to write the streaming data interpolated to vertices. Set to 0 for cell-centered data. Default: 0.
NewMovieDumpNumber (internal)
Counter for streaming data files. This should equal the cycle number.
MovieTimestepCounter (internal)
Timestep counter for the streaming data files.
MovieDataField (external)
A maximum of 6 data fields can be written in the streaming format. The data fields are specified by the array element of BaryonField, i.e. 0 = Density, 7 = HII Density. For writing temperature, a special value of 1000 is used. This should be improved to be more transparent in which fields will be written. Any element that equals INT_UNDEFINED indicates no field will be written. Default: INT_UNDEFINED x 6
NewMovieParticleOn (external)
Set to 1 to write all particles in the grids. Set to 2 to write ONLY particles that aren’t dark matter, e.g. stars. Set to 3/4 to write ONLY particles that aren’t dark matter into a file separate from the grid info. (For example, MoviePackParticle_P000.hdf5, etc. will be the file name; this will be very helpful in speeding up the access to the star particle data, especially for the visualization or for the star particle. See AMRH5writer.C) Set to 0 for no particle output. Default: 0.

Simulation Identifiers and UUIDs

These parameters help to track, identify and group datasets. For reference, Universally Unique Identifiers (UUIDs) are opaque identifiers using random 128-bit numbers, with an extremely low chance of collision. (See Simulation Names and Identifiers for a longer description of these parameters.)

MetaDataIdentifier (external)
This is a character string without spaces (specifically, something that can be picked by “%s”), that can be defined in a parameter file, and will be written out in every following output, if it is found.
MetaDataSimulationUUID (internal)
A UUID that will be written out in all of the following outputs. Like MetaDataIdentifier, an existing UUID will be kept, but if one is not found, and new one will be generated.
MetaDataDatasetUUID (internal)
A UUID created for each specific output.
MetaDataRestartDatasetUUID (internal)
If a MetaDataDatasetUUID UUID is found when the parameter file is read in, it will written to the following datasets. This is used to track simulations across restarts and parameter adjustments.
MetaDataInitialConditionsUUID (internal)
This is similar to MetaDataRestartDatasetUUID, except it’s used to track which initial conditions were used.