MAXMEM: Difference between revisions
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{{TAGDEF|MAXMEM|[integer]|2800}} | {{TAGDEF|MAXMEM|[integer]|2800 (VASP 5.4.4. and older) | automatically set as of VASP.6 }} | ||
Description: {{TAG|MAXMEM}} specifies the maximum memory one MPI rank will attempt to allocate (in MByte). | Description: {{TAG|MAXMEM}} specifies the maximum memory one MPI rank will attempt to allocate (in MByte). | ||
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MAXMEM to the available memory per core minus 200 Mbyte. For instance, if one node is equipped | MAXMEM to the available memory per core minus 200 Mbyte. For instance, if one node is equipped | ||
with 12 Gbyte, and 6 MPI ranks share this memory, the recommended setting is 12*1024/6-200 = 1848. | with 12 Gbyte, and 6 MPI ranks share this memory, the recommended setting is 12*1024/6-200 = 1848. | ||
As of VASP.6 the default value of MAXMEM is set to 90 percent of the available memory per MPI rank of the node. If more than one computation node is used, the minimum of all nodes is used. | |||
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[[GW calculations]] | [[GW calculations]] | ||
{{sc|MAXMEM|Examples|Examples that use this tag}} | {{sc|MAXMEM|NTAUPAR|Examples|Examples that use this tag}} | ||
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[[Category:INCAR]][[Category:Many-Body Perturbation Theory]][[Category:GW]] | [[Category:INCAR]][[Category:Many-Body Perturbation Theory]][[Category:GW]][[Category:Low-scaling GW and RPA]] | ||
Revision as of 11:22, 12 August 2019
MAXMEM = [integer]
Default: MAXMEM = 2800 (VASP 5.4.4. and older)
Description: MAXMEM specifies the maximum memory one MPI rank will attempt to allocate (in MByte). Since, the default varies somewhat between VASP versions, it is safer to set this flag manually. Currently the flag is only inspected in few selected routines, such as the GW or RPA routines that can use excessive amounts of memory. It is recommended to set MAXMEM to the available memory per core minus 200 Mbyte. For instance, if one node is equipped with 12 Gbyte, and 6 MPI ranks share this memory, the recommended setting is 12*1024/6-200 = 1848.
As of VASP.6 the default value of MAXMEM is set to 90 percent of the available memory per MPI rank of the node. If more than one computation node is used, the minimum of all nodes is used.