[molpro-user] How Much Memory is Needed for Molpro?

王黎明 wanglm at scut.edu.cn
Sun Mar 6 04:32:56 CET 2016

Dear All,

We are having MEMORY problem when trying CCSD(T)-F12 on an open-shell species C6H7O3.

We have tried the calculations on nodes with 64 GB memory (12 cores or 24 cores). 
In the input file, we have specified
and run molpro as
      molpro -n 6 xx.inp 
      molpro -n 4 xx.inp 
or    molpro -n 4 -t 3 xx.inp
We tried the calcs on SINGLE node. The working nodes were randomly assigned from a large array of nodes from a supercomputer system.

Here is my input file. We are using Molpro 2015 Binary version (Version 2015.1 linked Jan 11 2016):

 ***,C6H6-OH-2OOs CCSD(T)-F12/cc-pVDZ-F12
 16           ! Number of Atoms
 The C6H6-1OH-2OOs @ BH&HLYP/6-311++G(2df,2p)
 C,  0.4896916042,  0.957210998,  -0.5274539138
 C,  -0.5220129911,  1.4593284657,  0.4548488539
 O,  1.798982791,  1.3481087669,  -0.2327248195
 C,  0.3795090277,  -0.5419399373,  -0.8054683779
 C,  -1.6990294152,  0.8682102219,  0.5700955585
 C,  -1.0328015783,  -1.0219854803,  -0.8108838961
 O,  1.1911345017,  -1.3117952708,  0.1244774923
 C,  -1.9813663576,  -0.3546568177,  -0.1700943447
 O,  0.7106684183,  -1.3358694996,  1.3257252382
 H,  0.2582067535,  1.4334500447,  -1.4783897973
 H,  -0.2697031013,  2.3521132212,  0.9965739711
 H,  2.1187148014,  0.8644543054,  0.5212382213
 H,  0.8821806298,  -0.7552332209,  -1.737738857
 H,  -2.4566695723,  1.2630433973,  1.2206075858
 H,  -1.2415583588,  -1.9549910075,  -1.299754911
 H,  -2.985861153,  -0.736941187,  -0.1583860036
 {UCCSD(T)-F12 SCALE_TRIP=1,MaxIT=200;}

The calculation finishes well in UHF and RHF, but in F12 part, we always got the following error message:
 ? Error
 ? actual memory layout of target op is different from the expected one
 ? The problem occurs in LoadF12Op

Another calc on a C10H17O system exits when starting CCSD(T) as
 insufficient memory available - require              103156065  have
 the request was for real wordsoo
with "MEMORY,800,M" and "molpro -n 6 xx.inp" on nodes with 64GB RAM. It looks like I don't get enough memory.

My question is: How much memory do I need to run such calculations?

I notice no matter how much memory I put in "MEMORY, xxx, M", the calculations qucikly takes almost all the memory available.
It looks to me that Molpro simply ignores the restriction from "MEMORY, xxx, M". Is there something here I did not set up correctly ? Can molpro run on a "memory reduced" mode?

Suggestions appreciated!

Liming Wang

Liming Wang, Ph D
School of Chemistry & Chemical Engineering
South China University of Technology
381, Wushan Rd.
Guangzhou, China 510640
E-Mail: wanglm at scut.edu.cn
ResearchGate: https://www.researchgate.net/profile/Liming_Wang6

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