When postprocessing a FLOTRAN analysis, I get a series of errors regarding the available memory. How can I avoid this?

On typical Windows systems, the maximum address space available to ANSYS is 2GB. However, once you are in the middle of an ANSYS run, this 2GB is broken up into pieces/blocks. Some blocks of memory are being used by arrays allocated by ANSYS. Other blocks of memory are being used by DLL`s (sometimes ANSYS DLL`s and sometimes system DLL`s). So when ANSYS needs large blocks of contiguous memory from the system, the system cannot find one to give to ANSYS and so it fails. The memory allocated by ANSYS at the time of failure is already pretty fragmented.

The fix is either to start ANSYS with a larger -m value or to run on a 64-bit Windows machine. With 64-bit memory address space, ANSYS can always find contiguous blocks of memory to address. By starting ANSYS with a larger -m value, that forces the program to grab 1 large block of memory address space from the system when ANSYS starts. That way ANSYS can work from that 1 large block of memory which no DLL can fragment. By default, ANSYS allocates 256 (MB). You may want to start with a -m value of 1000->1500. Also, if you are using WinXP, you may want to try the /3GB switch. This allows ANSYS to address 3GB of memory instead of 2GB of memory.

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