iOpenShell » Q-Chem specific questions » Insufficient of Memory for MP2 geom optimization

Insufficient of Memory for MP2 geom optimization

Page: 1

Author Post
Member
Registered: Jun 2008
Posts: 31
Hi

I have problem to compute a MP2 optimization with Q-Chem 5.2 on a workstation with 40 cores and 192MB memory.

(1) If I simply set MEM_TOTAL to 190GB, the job will crash with error message
Insufficient memory for semidirect MP2

(2) I set MEM_STAT = 5000, the job start to write a 12 huge files 65.x (2GB each) on local scratch, and then hang over there and without any further update in few hours.

(3) If I set the MEM_STAT to a very large value, e.g. 10GB, the insufficient memory error come up again.


Is there a way to estimate the correct memory requirement for a MP2 job. Thanks!


P.S. it is very disappointing that Q-Chm does not support MPI parallelization for MP2.

Regards,
Dominic Chien


$molecule
0 1
N -0.5293338 3.8082003 4.2773910
C -1.1824460 4.1540804 3.1338951
N -2.4575498 4.6130624 3.1970503
N -0.5533995 4.0388586 1.9384299
C 0.7297251 3.5843111 1.8535597
N 1.3686089 3.2448279 3.0097644
N 1.4026793 3.0036984 5.3510698
N 1.3983065 3.4727549 0.5693438
C 0.6521507 3.6927362 -0.6569922
N -0.6984563 3.8810775 -0.6311025
C -1.4046891 4.0770573 -1.7716784
N -2.7481894 4.2595732 -1.7242574
N -0.7611371 4.0890444 -2.9714307
C 0.5869848 3.9035583 -3.0174330
N 1.2791457 3.7062437 -1.8681501
C 2.8113789 3.1418742 0.5121781
N 3.4443020 2.9638713 -0.6808687
C 4.7644284 2.6580374 -0.7384216
H 5.2465563 2.5215890 -1.6965893
N 5.4783347 2.5242755 0.4048621
C 4.8677208 2.6973292 1.6014503
H 5.4324492 2.5919958 2.5175022
N 3.5473329 3.0034574 1.6501308
C 0.7514015 3.3505002 4.2125552
C -1.4647581 4.2855768 -4.1233717
C -3.4487350 4.4540234 -2.8720165
N -2.8081742 4.4675237 -4.0701661
N 1.2296107 3.9160102 -4.2122288
C 0.5285259 4.1132552 -5.3592439
N -0.8169186 4.2973114 -5.3153503
H -4.5195775 4.5983399 -2.8317531
H 1.0429999 4.1233990 -6.3102179
C 0.7773727 3.1133788 6.5523247
N -0.4998813 3.5718319 6.6191321
C -1.1558793 3.9203389 5.4838517
N -2.4310233 4.3801325 5.5412281
C -3.0803879 4.7266633 4.3991685
H 1.2981118 2.8352920 7.4582153
H -4.096181 5.0941058 4.4470828
$end

$rem
MEM_TOTAL 190000
MEM_STATIC 5000
BASIS = 6-31++G**
JOB_TYPE = Optimization
METHOD = MP2
! set scf_convergence to 5 to speed up the performantion evaluation
SCF_CONVERGENCE = 5
GEOM_OPT_MAX_CYCLES = 100
N_FROZEN_CORE fc
$end
Administrator
Registered: Oct 2017
Posts: 22
Dear Dominic,

I tried to run this job on our node with 240 GB of RAM, 20 cores - it runs without errors, and computes gradient. I think that your the value of MEM_TOTAL is too close to the physical limit. I would use ~180000 instead in your case.

If you need an optimized geometry, maybe RI-MP2 can fulfill your needs?

Page: 1

iOpenShell » Q-Chem specific questions » Insufficient of Memory for MP2 geom optimization