Roman Zubatyuk
zubatyuk@gmail.com
I got insufficient memory error while performing large MP2 gradient calculation (Nocc=129, Ncore=52, Nvirt=981, distributed over 24 nodes each having 1GB of RAM). There are four options for the code those 'seriously affect amount of memory required': MXI, MXPQ, RSIZE1 and RSIZE2. Regarding this I have two questions:
1. If I'll halve MXI (or MXPQ), integral half-transformation (first or second) will be performed in two passes and thus approximately twice less memory will be needed. Am I right? Should I also change RSIZE1 (or RSIZE2)?
2. Is there a formula to estimate memory requirement for various steps of MP2 calculation? Or the only solution is to perform check run? Should I run it in parallel, or serial check run will be sufficient?
Thanks in advance.
Roman Zubatyuk