MSC Nastran jobs sometimes comes out in the middle with an error like below in .f06 file.
*** USER FATAL MESSAGE 6136 (UDSFA)
INSUFFICIENT CORE FOR NUMERIC PHASE OF SPARSE DECOMPOSITION.
USER ACTION: INCREASE CORE BY 126613566 WORDS
This happens when ever insufficient memory is allocated to the job or exceeds the initial estimated memory calculated by the application.
This can be easily solved by setting mem=<no of GBs> in the Nastran command line. So the question is how to calculate the required memory to put in “mem”?
Here is the answer of that.
Open the .f04 file and note the “TOTAL MSC.NASTRAN MEMORY LIMIT” value
Eg. $vim sample_job.f04
** MASTER DIRECTORIES ARE LOADED IN MEMORY.
USER OPENCORE (HICORE) = 120744623 WORDS
EXECUTIVE SYSTEM WORK AREA = 329621 WORDS
MASTER(RAM) = 66497 WORDS
SCRATCH(MEM) AREA = 819300 WORDS ( 100 BUFFERS)
BUFFER POOL AREA (GINO/EXEC) = 303511 WORDS ( 37 BUFFERS)
TOTAL MSC.NASTRAN MEMORY LIMIT = 122263552 WORDS
Now you can calculate the required memory using the below formula
mem= ((TOTAL MSC.NASTRAN MEMORY LIMIT + INCREASE CORE BY value) x 4 / (1024^3) )gb
eg mem=((122263552+126613566) x 4 / (1024 ^3) = 0.927gb
So the required memory is .927gb or 1gb (after Rounding off adjustment). The same can you added in the memory option “mem=1gb”.