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running_molpro_on_parallel_computers [2022/01/05 15:06]
qianli [Memory specifications]
running_molpro_on_parallel_computers [2022/04/07 09:23] (current)
doll [Memory specifications] ga_frac = 0.25 in src/mpp/memory_settings.F90
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 In order to facilitate the memory splitting, the ''-M'' option is provided (in the following, its value is denoted $M$).  In order to facilitate the memory splitting, the ''-M'' option is provided (in the following, its value is denoted $M$). 
-With this, the total memory allocatable by Molpro can be specified, and the memory is split 50-50 for stack and GA in DF/PNO calculations, and 80-20 in other calculations.+With this, the total memory allocatable by Molpro can be specified, and the memory is split 50-50 for stack and GA in DF/PNO calculations, and 75-25 in other calculations.
 Thus, unless specified otherwise, in DF/PNO calculations the stack memory per process is $m=M\cdot N/(2\cdot n)$ and the total GA memory is $G=N\cdot M/2$. Thus, unless specified otherwise, in DF/PNO calculations the stack memory per process is $m=M\cdot N/(2\cdot n)$ and the total GA memory is $G=N\cdot M/2$.
 If the use of GA in storing large data structure is desired, it is recommended to provide a default ''-M'' value in .molprorc (**do not do so for disk-based calculation, see [[#disk option]]**), e.g. ''-M=25g'' for a dedicated machine with 256 GB of memory and 20 cores (.molprorc can be in the home directory and/or in the submission directory, the latter having preference). Then each Molpro run would be able to use the whole memory of the machine with reasonable splitting between stack and GA. The default can be overwritten or modified by molpro command line options ''-m'' and/or ''-G'', or by input options (cf. section [[general program structure#memory allocation|memory allocation]]), the latter having preference over command line options. If the use of GA in storing large data structure is desired, it is recommended to provide a default ''-M'' value in .molprorc (**do not do so for disk-based calculation, see [[#disk option]]**), e.g. ''-M=25g'' for a dedicated machine with 256 GB of memory and 20 cores (.molprorc can be in the home directory and/or in the submission directory, the latter having preference). Then each Molpro run would be able to use the whole memory of the machine with reasonable splitting between stack and GA. The default can be overwritten or modified by molpro command line options ''-m'' and/or ''-G'', or by input options (cf. section [[general program structure#memory allocation|memory allocation]]), the latter having preference over command line options.