Memory Allocation

Memory is dynamically allocated for a run. The allocation starts with the initial memory (or minimum, memory).

The default setting for the upper bound of the dynamic memory allocation is 8 GB. This setting can be changed by using the SYSSETTING option OS_RAM, or by defining the -len option in the run script, or OS_RAM in the configuration file. The script overwrites the environment variable.

OptiStruct will always attempt to assign enough memory for a minimum core solution.

The initial memory is 10% of the dynamic memory upper bound by default. This setting can be changed by using the SYSSETTING option MINLEN, -minlen run option, or MINLEN in the configuration file.

A check run can be very helpful in estimating the memory and disk space usage. In a check run, the memory necessary is automatically allocated.

The solver automatically chooses an in-core, out-of-core, or minimum core solution based on the memory allocated. A solution type can be forced by defining the -core option in the run script; the memory necessary for the specified solution type is then assigned.

Refer to Memory Limitations for detailed information on the following topics: virtual versus physical memory, and automatic memory allocation versus fixed memory runs.