All requests for technical support from the VASP group must be addressed to:

Difference between revisions of "MAXMEM"

From Vaspwiki
Jump to navigationJump to search
(Related Tags and Sections)
(One intermediate revision by the same user not shown)
Line 12: Line 12:
== Related Tags and Sections ==
== Related Tags and Sections ==
[[GW calculations]]
[[GW calculations]], [[ACFDT calculations]],

Latest revision as of 13:09, 12 August 2019

MAXMEM = [integer]
Default: MAXMEM = 2800 (VASP.5.4.4. and older), automatically set as of VASP.6 

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 and if more than one computation node is used, the minimum of all nodes is used. The available memory in RAM is estimated by searching the file "/proc/meminfo" for the entry "MemFree:". Note that "/proc/meminfo" is present on any Linux system and stored in RAM. In case that the file cannot be found, MAXMEM is set to 2800.

Related Tags and Sections

GW calculations, ACFDT calculations, NTAUPAR

Examples that use this tag