I/O Options EntryUsed to define the external libraries and external files to be loaded into OptiStruct.

External functions can be implemented within dynamic libraries (.dll) under Windows, shared libraries (.so) under Linux, by using Altair Compose Open Matrix Language (.oml) on Windows, and external files by using Microsoft Excel (.xls or .xlsx) on Windows.

## Definitions

Argument Options Description
type <DRESP3, MATUSR, MATUSHT, QVOL, PCONV, QBDY, SPCD>

No default

Identifier that defines the type of library or file to be loaded into OptiStruct.
DRESP3
Specifies an external file or library to define external responses.
MATUSR
Specifies an external .dll file (Windows) or an external .so file (Linux) to input user-defined structural material data. 2
MATUSHT
Specifies an external .dll file (Windows) or an external .so file (Linux) to input user-defined thermal material data.
QVOL
Specifies an external .dll file (Windows) or an external .so file (Linux) to input user-defined volumetric heat addition data.
PCONV
Specifies an external .dll file (Windows) or an external .so file (Linux) to input user-defined free-convection coefficient data.
QBDY
Specifies an external .dll file (Windows) or an external .so file (Linux) to input user-defined uniform heat flux data.
SPCD
Specifies an external .dll file (Windows) or an external .so file (Linux) to input user-defined ambient temperature data.
group <Character string>

No default

group identifier that is referenced by a DRESP3, MATUSR, MATUSHT, PCONVLIB, QVOLLIB, QBDYLIB, or SPCDLIB Bulk Data Entry.
path <Path including file name and extension>

No default

The path to the external shared or dynamic library to be loaded.

1. Absolute paths (those starting with a drive letter or a slash) will be used as they are defined on the LOADLIB card. Relative library or file paths will be appended to the path corresponding to the input deck's location. For any type of shared library reference (except MATUSR, 2), the default location OptiStruct looks for is in the present working directory (./).
2. For MATUSR, the shared library should be identified in one of the following ways:
1. Directly specify the absolute path pointing to the shared library on the LOADLIB entry, or
2. Add the absolute path to the shared library in the following environment variables:
• Linux: LD_LIBRARY_PATH
• Windows: PATH

For MATUSR, even though the shared library exists in the working directory, it is not used unless identified via one of these methods.

3. The total length of information on this card is limited to 200 characters (including the card name and spaces between arguments). This data can be on a single line or span multiple continuation lines. Refer to I/O Options and Subcase Information Entries Guidelines for an example showing how to enter long file names on multiple lines.
4. The application or external library to use is solely based on the file extension identified via the path argument.