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Latest revision as of 10:30, 13 May 2019
Memory
What are the large objects in the code and what do we do about them?
- Non-DF Hessians: o^2 v^2
- TAO, TMO, D: M N(N+1)/2
I used to think that it was the Hessians that limited us, but this is not true. The objects of size M N(N+1)/2 are larger for large problems.
For pyridine daTZ basis:
- Hessians (size of each of the 10): 878 MB
- TAO, TMO, D (each of these): 1833 MB
See the problem? With density-fitting, the Hessians become about 22 MB in size. This is negligible. But, the TAO, TMO, and D objects remain as large. Something must be done! And quickly!!!