IOSS  2.0
IOSS API Documentation

Availability

The IOSS library source code is available on Github at https://github.com/gsjaardema/seacas

For bug reports, documentation errors, and enhancement suggestions, contact:

Properties

General Properties

Property Value Description
LOGGING on/[off] enable/disable logging of field input/output
LOWER_CASE_VARIABLE_NAMES [on]/off Convert all variable names on database to lowercase; replace ' ' with '_'
USE_GENERIC_CANONICAL_NAMES on/[off] use block_{id} as canonical name of an element block instead of the name (if any) stored on the database. The database name will be an alias.
MINIMIZE_OPEN_FILES on/[off] If on, then close file after each timestep and then reopen on next output

Auto-Decomposition-Related Properties

Property Value Description
MODEL_DECOMPOSITION_METHOD {method} Decompose a DB with type MODEL using method
RESTART_DECOMPOSITION_METHOD {method} Decompose a DB with type RESTART_IN using method
DECOMPOSITION_METHOD {method} Decompose all input DB using method
PARALLEL_CONSISTENCY [on]/off On if the client will call Ioss functions consistently on all processors. If off, then the auto-decomp and auto-join cannot be used.
RETAIN_FREE_NODES [on]/off In auto-decomp, will nodes not connected to any elements be retained.
LOAD_BALANCE_THRESHOLD {real} [1.4] CGNS-Structured only – Load imbalance permitted Load on Proc / Avg Load

Valid values for Decomposition Method

Method Description
rcb recursive coordinate bisection
rib recursive inertial bisection
hsfc hilbert space-filling curve
metis_sfc metis space-filling-curve
kway metis kway graph-based
kway_geom metis kway graph-based method with geometry speedup
linear elements in order first n/p to proc 0, next to proc 1.
cyclic elements handed out to id % proc_count
random elements assigned randomly to processors in a way that preserves balance (do not use for a real run)
external Files are decomposed externally into a file-per-processor in a parallel run.

Output File Composition – Single File output from parallel run instead of file-per-processor

Property Value
COMPOSE_RESTART on/[off]
COMPOSE_RESULTS on/[off]
PARALLEL_IO_MODE netcdf4, hdf5, pnetcdf, (mpiio and mpiposix are deprecated)

Properties Related to byte size of reals and integers

Property Value Description
INTEGER_SIZE_DB [4] / 8 byte size of integers stored on the database.
INTEGER_SIZE_API [4] / 8 byte size of integers used in api functions.
REAL_SIZE_DB 4 / [8] byte size of floating point stored on the database.
REAL_SIZE_API 4 / [8] byte size of floating point used in api functions.

Properties related to underlying file type (exodus only)

Property Value Description
FILE_TYPE [netcdf], netcdf4, netcdf-4, hdf5 Underlying file type (bits on disk format)
COMPRESSION_LEVEL [0]-9 In the range [0..9]. A value of 0 indicates no compression, will automatically set file_type=netcdf4, recommend <=4
COMPRESSION_SHUFFLE on/[off] to enable/disable hdf5's shuffle compression algorithm.
MAXIMUM_NAME_LENGTH [32] Maximum length of names that will be returned/passed via api call.
APPEND_OUTPUT on/[off] Append output to end of existing output database
APPEND_OUTPUT_AFTER_STEP {step} Max step to read from an input db or a db being appended to (typically used with APPEND_OUTPUT)
APPEND_OUTPUT_AFTER_TIME {time} Max time to read from an input db or a db being appended to (typically used with APPEND_OUTPUT)

Properties for the heartbeat output

Property Value Description
FLUSH_INTERVAL int Minimum time interval between flushing heartbeat data to disk. Default is 10 seconds
TIME_STAMP_FORMAT [H:M:S] Format used to format time stamp. See strftime man page
SHOW_TIME_STAMP on/off Should the output lines be preceded by the timestamp
PRECISION 0..16 [5] Precision used for floating point output.
FIELD_WIDTH 0.. Width of an output field. If 0, then use natural width.
SHOW_LABELS on/[off] Should each field be preceded by its name (ke=1.3e9, ie=2.0e9)
SHOW_LEGEND [on]/off Should a legend be printed at the beginning of the output showing the field names for each column of data.
SHOW_TIME_FIELD on/[off] Should the current analysis time be output as the first field.

Experimental

Property Value Description
MEMORY_READ on/[off] experimental
MEMORY_WRITE on/[off] experimental
ENABLE_FILE_GROUPS on/[off] experimental

Debugging / Profiling

Property Value Description
LOGGING on/[off] enable/disable logging of field input/output
DECOMP_SHOW_PROGRESS on/[off] show memory and elapsed time during autodecomp.
DECOMP_SHOW_HWM on/[off] show high-water memory during autodecomp
IOSS_TIME_FILE_OPEN_CLOSE on/[off] show elapsed time during parallel-io file open/close/create
CHECK_PARALLEL_CONSISTENCY on/[off] check Ioss::GroupingEntity parallel consistency

License

The IOSS library is licensed under the BSD open source license.

 Copyright (c) 1999-2017 National Technology & Engineering Solutions
 of Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
 NTESS, the U.S. Government retains certain rights in this software.

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   notice, this list of conditions and the following disclaimer.

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