Large GAs used without preallocation warning

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Jacopo LUPI

Jan 14, 2022, 3:59:44 AMJan 14
to molpro-user
Dear Molpro users and developers,

I am running with molpro 2021.3 some F12 geometry optimizations on small vdW complexes. In the log file, in the middle of MP2-F12 iteration, this warning appears:

? Warning
 ? Large GAs used without preallocation
 ? The problem occurs in mpp
 The results below MAY BE INCORRECT!
 See "Running Molpro on parallel computers" in Molpro manual.

Should I be worried about this?

Here I attach the input file


 B1=                  1.34476905 ANG
 B2=                  2.27450744 ANG
 A1=                175.35583635 DEG
 B3=                  0.96128241 ANG
 A2=                118.01765989 DEG
 D=                  54.38103712 DEG



Thank you in advance

Best regards
Jacopo Lupi
PhD Student in Methods and Models for Molecular Sciences
SMART Laboratory
Scuola Normale Superiore
Piazza dei Cavalieri 7, 56126 Pisa (Italy)

Jan 14, 2022, 2:55:53 PMJan 14
to molpro-user
Yes, you should be worried and check out "Running Molpro on parallel computers" in Molpro manual.

I take that you are running the calculation on multiple nodes? Some file I/O is then implemented using the GlobalArrays library, and failure in preallocation is know to give wrong results with some computers. You can pre-allocate some GA memory, use a mpi-pr build of Molpro, or run single-node calculations to get things right.
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