Returns the current resident set size (memory used) for the program.
mem - memory usage in bytes
Options Database Key#
The memory usage reported here includes all Fortran arrays
(that may be used in application-defined sections of code).
This routine thus provides a more complete picture of memory
PetscMallocGetCurrentUsage() for codes that employ Fortran with
This value generally never decreases during a run even if the application has freed much of its memory that it allocated