# SYSSETTING

I/O Options EntryUsed to alter system settings. Any setting defined here may be over-ridden by command line arguments (Run Options). Most of these options can also be specified in one of the config files (Configuration File).

## Format

SYSSETTING(setting=option_list,setting=option_list, ...)

## Examples

SYSSETTING(RAMDISK=100)
SYSSETTING(SCRFMODE=buffered,stripe)
SYSSETTING(SPSYNTAX=mixed,RAMDISK=100,SCRFMODE=buffered,stripe,OS_RAM=1234)

## Definitions

Setting Options Description
YES
Second order solid elements with missing mid-side nodes are allowed in the solution. Also, if matching edges of two adjacent second order elements are both missing mid-side nodes, then they are equivalenced together.
DUP
Second order solid elements with missing mid-side nodes are allowed in the solution. However, if matching edges of two adjacent second order elements are both missing mid-side nodes, then they are not equivalenced together.
NO (Default)
Second order solid elements with missing mid-side nodes are not allowed and OptiStruct will error out for such cases.
AXEGORD <0, 1> Element grid numbering for axisymmetric elements.
0 (Default)
Element grids are numbered in the order in which they are encountered as you move along the perimeter of the element. First grid is a corner grid, the next is an edge grid, and this alternating pattern repeats until all grids are accounted for. 10
1
Element grids are numbered by first listing all corner grids and then all the corresponding edge grids are listed, for each element.
BARPROP <STRICT, MIXED>
STRICT (Default)
The CBAR and CBEAM beam element connections cannot reference the PBEAM beam property entries, respectively.
MIXED
The CBAR and CBEAM beam element connections can reference the PBEAM and PBAR beam property entries, respectively.
BUFFSIZE BUFFSIZE = 65537 The maximum size in 8 byte words of the records of data written to the .op2 file.
-1
Turns off buffering
CARDLENGTH <Integer>

Default = 80

Defines the number of characters read on a single line in the I/O Options and Subcase Information Entry sections. This can vary between 80 and 132 characters.

In the Bulk Data Entry section, CARDLENGTH applies to free and long free format lines only (fixed and long format lines are always limited to 72 characters).

CORE <IN, OUT, MIN> This is same as the -core run option, but allows control from the input file.
IN
In-core solution is forced
OUT
Out-of-core solution is forced
MIN
Minimum core solution is forced
DUPGRTOL <Real>

No default

Controls the elimination of potential duplicate GRID entries based on the distance between the grids. If GRID points with the same ID are closer than the specified distance (DUPGRTOL), they are considered to be equivalent. If GRID points with the same ID are farther than the specified distance, OptiStruct errors out.
DUPTOL Integer <0-5> Controls accuracy used during elimination of potential duplicate cards. Two cards with identical ID's are replaced by the first one, if all integer values on both cards match exactly, and all float values match with accuracy controlled by this setting, otherwise identical IDs are flagged as ERROR. Currently only GRID, CORDxx, and base MAT/PROP entry duplicates are allowed (MATX, MATT, and PROPX entries do not allow duplicates).
0 (Default)
No tolerance, the values defined must be an exact match.
1
For standard fixed 8-character without exponent, the value must match up to 6 decimal places.
2
For standard fixed 8-character without exponent, the value must match up to 5 decimal places.
3
For standard fixed 8-character without exponent, the value must match up to 4 decimal places.
4
For standard fixed 8-character without exponent, the value must match up to 3 decimal places.
5
For standard fixed 8-character without exponent, the value must match up to just 2 decimal places.

If values are too large or too small to represent without exponent, both values must match exactly when converted to 8-character form. Also, for negative values, the accuracy is one digit lower.

ECHOFMT <FIXED,LONG, FREE8,FREE12, FREE16,AUTO> Used to determine the ECHO formatting option for ECHO results. Formatting options on the ECHO entry are disabled as of OptiStruct 14.0.
FIXED
Fixed format
LONG
Long format
FREEn
n=8,12,16: selects the FREE format with different float point precision. It reserves up to n characters for each real valued field. For example, FREE12 option allows real value field to be echoed with up to 12 characters.
AUTO (Default)
Selects the FIXED format automatically, but switches to FREE12 option if real valued data is present in a particular line.
ELEMENTID <UNIQUE, ALLOWFIX> Controls the numbering scheme of scalar elements (CELASi, CMASSi, CDAMPi, PLOTELi Bulk Data Entries) and PLOTEL elements.
UNIQUE (Default)
Requires all scalar and PLOTEL elements have unique element IDs.
ALLOWFIX
Allows OptiStruct to automatically fix duplicate ID for scalar and PLOTEL elements. If scalar and PLOTEL elements have the same IDs as some other elements, OptiStruct renumbers the IDs of all scalar and PLOTEL elements by adding a large offset value.
ELMERRCMF <YES, NO> Controls output of elements failing quality checks to the HM.elcheck.cmf file.
YES
Element quality checks are automatically turned on even if PARAM,CHECKEL,NO is present. Along with regular element quality errors, the elements which failed due to negative Jacobian and collapsed grids are also printed to the HM.elcheck.cmf file in new categories called “jacobian” and “collapsed", respectively.
NO (Default)
Element quality checks are not automatically turned on if PARAM,CHECKEL,NO is present. The additional categories of element failures are not printed to the HM.elcheck.cmf file.
FDOFLERR <YES, NO> Controls if loads on free degrees-of-freedom will error out.
YES
Run will error out, if loads on free degrees-of-freedom exist in the model.
NO (Default)
Run will not result in an error, if loads on free degrees-of-freedom exist in the model.
GPFMPC <BOTH, FMPC, SEPAR> Controls the handling of Grid Point Force contribution from MPCs and rigid elements (RBEx, RROD, RSPLIN and so on) in the .gpf file.
BOTH (Default)
F-MPC is output in addition to MPC and separate rigid element GPF contributions.
FMPC
Only F-MPC is output. In this case, rigid element GPF contributions and MPC GPF contributions are not output separately in the .gpf file.
SEPAR
F-MPC is not output. Only separated items are output; rigid element GPF contributions and MPC GPF contributions are output separately.

F-MPC printing in the .gpf file is the total grid point force value of all the MPC and rigid body elements in the .gpf file, meaning F-MPC is the sum of MPC and rigid element contributions.

H3DVTAG <YES, NO>

Default = NO

Appends the version of the H3D format used, onto the .h3d file output by OptiStruct.

So the results file would be {filename}.h3d11 or {filename}.h3d12.

Note: It is not possible to select the H3D format used for output; this is built into the executable.
HOSTMEM <YES, NO, blank> This setting is available for MPI runs.
YES or blank
This is the default interpretation of memory options defined by -fixlen, -minlen, -maxlen, -len, and -ramdisk. It means that the specified memory options input the total memory of all processes on each host.
This can also be set using the run option, -hostmem yes/blank.
NO
This switches the interpretation of memory options defined by -fixlen, -minlen, -maxlen, -len, and -ramdisk to the memory for each MPI process.
Note: -hostmem yes or SYSSETING,HOSTMEM,YES is the default starting from OptiStruct 2021.1 (prior to this release, the default behavior was consistent with -hostmem no or SYSSETTING,HOSTMEM,NO).
IR4MECH <YES, NO> With SYSSETTING(IR4MECH = YES) in conjunction with PARAM,INREL,-2, the EIGRL-based Inertia Relief will be activated for all static subcases with SPC’s in the model.
Note: For subcases without SPC’s, if the number of degrees of freedom is equal to 6, the constraint-based method will be used. If number of degrees of freedom is more than 6, then no inertia relief is applied.
M2ONLYFKM <ALLOW, NO>

Default = NO

When SYSETTING(M2ONLYFKM) is set to ALLOW, the MSS1 field on the MATFAT entry will interpreted as the MSS2 value which is used for FKM mean stress correction.
Note: If this setting is set to ALLOW, the MSS2, MSS3, MSS4 fields should be blank.
MAT9ORT <NU31, NU13>
NU31 (Default)
The 8th field on the MAT9OR entry is interpreted as NU31.
NU13
The 8th field on the MAT9OR entry is interpreted as NU13.
MAXLEN <Integer> Used to define the maximum allowable amount of memory to be used in MB. There is no default.

MAXLEN is not supported when the MUMPS solver is used (including -ddm parallel runs).

MAXRATIO <value, option>

Value: <Real>

Option: ERROR, WARN

Default = No default for value, but ERROR is the default if a value is specified and option field is blank.

Defines the maximum allowed value of the ratio of terms on the diagonal of the stiffness matrix to the corresponding diagonal terms of the triangular factor matrix during decomposition.

If the value of the ratio exceeds that specified on the value field, then OptiStruct will terminate the run with an error (ERROR) or issue a warning (WARN), depending on the value of the Option field. For additional information, refer to the Comments in PARAM,MAXRATIO.

MESHNLPTB <0, 1, 2> H3D output flag for Nonlinear Static (NLSTAT) preloaded linear analysis.
0 (Default)
Use the NLSTAT-deformed mesh and the BYSUB H3D output (refer to OUTPUT,H3D,BYSUB) if large-displacement NLSTAT preloaded linear analysis is present; otherwise, use the initial mesh and the single-file H3D output.
1
Use the NLSTAT-deformed mesh and the BYSUB H3D output for NLSTAT preloaded linear analyses.
2
Use the initial mesh and the single-file H3D output for NLSTAT preloaded linear analyses.

If the value of MESHNLPTB is outside the allowable range (other than 0, 1, or 2), an ERROR is issued both in the .out file and the hwsolver.mesg file.

MINLEN <Integer> Used to define the initial memory allocation in MB. The default is 10% of OS_RAM. This is the same as the legacy command, OS_RAM_INIT.
NPROC

(legacy command: CPU)

<Integer>

Default =1

Same as -nproc and -cpu options (Run Options for OptiStruct). Sets number of processors in a multiprocessor (SMP) run.
OS_RAM <RAM in Mbytes>

Default = 8 GB

Memory limit in Mb. The solver will attempt to run at least the minimum core solution regardless of the memory limit. Refer to Memory Handling in the User Guide for details.
PBUSHFORM <PEN, LAG> The PBUSHFORM setting controls the formulation of RIGID CBUSH elements.
PEN (Default)
This option selects the default penalty formulation. A very high relative stiffness (relative to the surrounding structure) is selected for the corresponding rigid CBUSH elements.
LAG
This option selects the Lagrange Multiplier Method. Constraint equations are used to enforce rigid behavior on the corresponding rigid CBUSH elements. This formulation is more stable when compared to the penalty formulation. Additionally, OptiStruct also tries to resolve double dependency issues.
RAM_SAFETY <Real>

Default = 1.0

Same as -rsf option. (Run Options for OptiStruct).
RAMDISK <RAM in Mbytes>

Default = See Comment 5

Specifies an area in RAM allocated to store information which otherwise would be stored in scratch files on the hard drive.
RESVEC6 <ON, OFF> Controls the generation of extra global residual vectors for Component Mode Synthesis (CMSMETH):
ON
Six additional global residual vectors are generated for Component Mode Synthesis (CMSMETH).
OFF (Default)
Additional global residual vectors are not generated for CMSMETH.
Note: Not supported for runs with AMLS or AMSES eigensolvers.
SAVEFILE <OUT, NONE, ALL, ext> Controls the behavior of the solver when an output file with the same name already exists when the program starts.
OUT (Default)
Preserve only .out and .stat files.
NONE
Allows the solver to overwrite any existing file.
ALL
Prevents overwriting output files by renaming an existing file by adding numeric suffix, for example, jobname.h3d will be renamed to jobname_nnn.h3d; where, nnn represents the smallest number for file which does not exists yet. This option tries to preserve files with all known extensions, and it may use a large amount of disk space if the same run is repeated multiple times.
ext
An arbitrary file extension (case insensitive, up to 9 characters). 8 9
SCRFMODE Primary options: BASIC, BUFFERED, UNBUFFER, STRIPE

Secondary option: MIXFCIO

Default =

1. For Linux: UNBUFFER
2. For Windows (without AMSES): BUFFERED, MIXFCIO
3. For Windows (using AMSES): BASIC
Allows for the selection of different modes of storing scratch files for a linear solver process (especially for out-of-core and minimum-core modes).
BASIC
Fortran mode, direct access file.
BUFFERED
Fortran buffered.
UNBUFFER
C i/o mode.
STRIPE
Stripe main solver files on multiple disks (except ones marked as slow).
MIXFCIO
Only valid when combined with BUFFERED.
Use C (native) I/O routines instead of Fortran read/write for main solver files. 7
SKIP10FIELD <CHECK, WARN>

Default = CHECK

To detect disallowed use of potential expansion of free format, error will be generated when 10 or more data fields is found on a Bulk Data card in free format. Use SKIP10FIELD=WARN to allow reading such card (extra fields will be disregarded instead of causing error).
SPSYNTAX <STRICT, CHECK, MIXED> Controls how strict the checks are in the reader for mixing GRIDs and SPOINTs.
STRICT
When both grid/component pairs (G#/C#) and grid lists for a given component (as on the alternate formats ASET1 and USET1 Bulk Data Entries) are defined, this option will require that the component be 0 or blank when the grid reference is a scalar point (SPOINT), and that the component be ≥ 1 when the grid reference is a structural grid point (GRID).
CHECK (Default)
When grid/component pairs (G#/C#) are defined, this option will require that the component be 0 or blank when the grid reference is a scalar point (SPOINT), and that the component be ≥ 1 when the grid reference is a structural grid point (GRID). But when grid lists for a given component (as on alternate formats ASET1 and USET1 Bulk Data Entries) are defined, this option will allow the grid reference to be scalar points (SPOINT) or structural grid points (GRID) when the component is 0, 1 or blank; interpreting all of these as 0 for scalar points and as 1 for structural grids.
MIXED
When grid/component pairs (G#/C#) and grid lists for a given component (as on alternate formats ASET1 and USET1 Bulk Data Entries) are defined, this option will allow the grid reference to be scalar points (SPOINT) or structural grid points (GRID) when the component is 0, 1 or blank; interpreting all of these as 0 for scalar points and as 1 for structural grids. 6
SRCHDCLR <YES, NO> Controls whether SRCHDIS is to be considered for contact definition in the presence of CLEARANCE.
YES (Default)
SRCHDIS is considered.
NO
SRCHDIS is not considered.
SYNTAX <ALLOWINT, STRICT> Controls how strict the syntax checker in the reader is.
ALLOWINT (Default)
Converts integer values to real values whenever real values are expected. In those instances, where the form of the input (Integer or Real) indicates the nature of the input (for example, when reading vector entries (X,Y,Z) with alternate form (GID), a negative integer value in the first field, or a non-blank value in the second or third field indicates the (X,Y,Z) format and all fields are read as real values.
STRICT
This option follows more closely with other Nastran codes, where integer values may only be entered in integer value fields and real values must be entered in real value fields. An error termination will occur if an integer value is placed in a real value field when this setting is chosen.
Note: This setting never changes results - it can only cause the rejection of files that do not follow the restrictions.
TABSTOPS TABSTOPS = 8 Allows you to change interpretation of TAB character in the input. By default, TAB stops are spaced by 8 columns, which is standard on all Unix/ Linux terminals. Possible values are 4 (used often on Windows) and 1 (replace each TAB with exactly one space).
Note: The default value of this setting is 0, if it is not included in input file.
Controls the setting of subcase-specific temperature-dependent material in structural linear static analysis. TLOADMAT is ignored for Nonlinear Static Analysis.
0 (Default)
All structural material properties are calculated based on the temperature field specified through the TEMP(MAT) or TEMP(INIT) entries (depending on order and priority).
1
TEMP(LOAD) is activated to specify the structural material properties instead of TEMP(MAT) or TEMP(INIT). TEMP(MAT) and TEMP(INIT) are ignored for the calculation of structural material properties (see Note).
2
TEMP(LOAD) is activated to specify the structural material properties instead of TEMP(MAT) or TEMP(INIT). TEMP(MAT) and TEMP(INIT) are ignored for the calculation of structural material properties (see Note). Thermal loading will not be included in the Static Analysis.
Note:
1. The Table outlines the effect of the different TLOADMAT values in Linear Static Analysis.
2. TLOADMAT,1 or 2 elevates TEMP(LOAD) to the same capabilities as TEMP(BOTH). If both TEMP(BOTH) and TEMP(LOAD) are specified, then the last instance in each subcase will take precedence.
3. TEMP(INIT) and TEMP(MAT) have no effect on material property calculation if TLOADMAT,1 or 2 is specified. TEMP(INIT), if present, will still be used to set the initial temperature for thermal strain calculation.
4. For detailed priority information, see Comments 5 and 6 in the TEMPERATURE entry.
UNDEFTEMP <STRICT, ZERO>
STRICT (Default)
OptiStruct will error out if there are some grid points without a specified temperature. The error message includes information about GRID ID, Element ID, and Load Set number.
ZERO
OptiStruct will use a value of zero for grids without a specified temperature (that is, a minimum of one, but not all, grid points in the model has a specified temperature). This allows users to revert to the behavior of versions prior to OptiStruct 13.0.
UNKNDATA <WARN, ERROR>
WARN (Default)
A Warning is issued whenever unrecognized and misspelled entries in the input deck exist.
ERROR
An Error is issued whenever unrecognized and misspelled entries in the input deck exist.
UNREFSID <WARN, ERROR> Controls OptiStruct behavior for missing NSGE, NSM, MPC, SPC Bulk Data Entries (if the corresponding control cards are present).
Note: This setting works only for the above, mentioned Bulk Data Entries.
WARN
Prints a warning instead of an error and allows the deck to run.
ERROR (Default)
Will error out.
UPDATE <quiet, verbose, strict, off, unique, permissive>

Defaults = quiet and strict

Controls the behavior of ASSIGN,UPDATE,<filename>.
quiet
Less output.
verbose
More output including old and new values.
strict
Do not allow non-supported cards in update deck (default).
off
Disable update.
unique
Each ID only once.
permissive
Allow all cards and repeat IDs.

Choose only one option from: quiet or verbose.

Choose only one option from: strict, off, unique, or permissive.

Table 1. Linear Static Analysis

1. The number of fields in this card is not limited to 10, but it is limited by the current line length (default 80).
2. Continuation lines are not allowed, multiple SYSSETTING cards are allowed.
3. The settings CPU and NPROC are interchangeable and can also be specified on the command line.
4. Each option except SCRFMODE must have exactly one argument. SCRFMODE arguments should be comma separated.
5. For RAMDISK setting:
• Use of a virtual disk instead of physical files may speed up solutions by reducing wait time to access physical disk drives. The use of RAMDISK will reduce the amount of memory available for the solver and for file buffering performed by the operating system (by Linux or Windows), and because of that it may not always reduce the wall clock time for the solution. The most impact can be observed on machines with very large physical memory (20GB or more) or when used to speed-up main solver scratch file access using the SCRFMODE setting.
• RAMDISK is automatically protected for overflow, so it is fine to specify 200MB for RAMDISK when the total amount of scratch files will be larger than that.
• RAMDISK is automatically specified for very small jobs, (less than 10,000 GRIDS). This can be disabled by specifying RAMDISK=0. Automatic RAMDISK is not allocated for fixed RAM jobs (the -fixlen command line option is used, see Run Options for OptiStruct).
6. For SPSYNTAX setting:
• When the component from a grid/component pair or for a list of grids (as on alternate formats ASET1 and USET1 Bulk Data Entries) is greater than 1, the grid reference must always be a structural grid (GRID).
• This control may also be set in the OptiStruct Configuration file.
• SYSSETTING (SPSYNTAX=mixed) is automatically enforced, if DMIG data is present in the model.
7. For SCRFMODE setting:
• This command controls the way scratch files from the linear equation solver are written to the disk. These files are usually written and read several times, often in random pattern, and this can have a significant impact on the total (wall clock) time for the solution of large jobs. The default mode is optimal in most configurations, but choosing between BASIC, BUFFERED or UNBUFFER may improve speed for some hardware and/or some types of solution sequences, especially jobs including Lanczos eigenvalue solver.
• In out-of-core and minimum-core solver modes, the solver creates one large scratch file for each subcase and this file may be optionally located across multiple TMPDIRs. In order to use this capability, SCRFMODE=STRIPE must be defined, otherwise the same method as for other files (BASIC, BUFFERED or UNBUFFER) is used, and this large file must therefore fit on a single TMPDIR.
• STRIPE mode can be used when all TMPDIRs (not marked as SLOW) are fully independent (that is, they should not be partitions on the same physical drive). This mode results in the access to all disks similar to RAID0 - consecutive blocks of data are split between separate TMPDIRs, and accessed in parallel, which can speed up disk access considerably.
Warning: Using STRIPE with TMPDIRs allocated on the same physical drive (even on different partitions) will usually slow down the solution by increasing wait times. Check with your system administrator for information on the actual hardware structure of your computer.
• STRIPE requires multiple TMPDIR cards and has effect only for out-of-core or minimum-core solutions.
• Most modern operating systems (Linux in particular) use excess available RAM for the buffering of disk i/o. The SCRFMODE command will have effect only for jobs which exceed the capabilities of this buffer.
• When AMSES is used on Windows, BASIC mode is enforced during AMSES calculations.
• The -scrfmode option can be specified on the command line (see Run Options) - this overrides any information specified in the input file.
8. The SAVEFILE option tries to preserve only files in the start directory, that is, this option has no effect when the input file is specified with a path, or the OUTFILE option defines a different location for all output files. Unless SAVEFILE,NONE is specified, standard .out and .stat files are always renumbered, even if they are created in different folder. All files are renumbered at program start - .out file is preserved first, and then the same NNN is used for all files found in the current folder. Only files with default names are preserved (that is those starting with the same root as outfile).
Note: This option may sometimes cause the solver to fail if it renames the file which is intended for the input.
9. Multiple SAVEFILE cards overwrite each other (the last one is in effect). Multiple SAVEFILE,ext cards can be used (up to 5 extensions can be defined), but using of any of the standard options (NONE/ALL/OUT) empties the list of previously defined extensions.
10. Example CQUAXI element grid numbering.
AXEGORD Corner Grid Points Edge Grid Points
C1 C2 C3 C4 E1 E2 E3 E4
0 G1 G3 G5 G7 G2 G4 G6 G8
1 G1 G2 G3 G4 G5 G6 G7 G8