https://wikis.ch.cam.ac.uk/cuc3/wiki/index.php?action=history&feed=atom&title=CamCASP%2FToDo%2FMemoryCamCASP/ToDo/Memory - Revision history2026-04-09T22:00:34ZRevision history for this page on the wikiMediaWiki 1.39.7https://wikis.ch.cam.ac.uk/cuc3/wiki/index.php?title=CamCASP/ToDo/Memory&diff=3553&oldid=previmport>Am592 at 10:57, 12 November 20082008-11-12T10:57:16Z<p></p>
<p><b>New page</b></p><div>[[ CamCASP ]] => [[ CamCASP/ToDo | ToDo ]] => Memory<br />
<br />
== Memory ==<br />
<br />
What are the large objects in the code and what do we do about them?<br />
<br />
# Non-DF Hessians: o^2 v^2<br />
# TAO, TMO, D: M N(N+1)/2<br />
<br />
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.<br />
<br />
For pyridine daTZ basis:<br />
# Hessians (size of each of the 10): 878 MB<br />
# TAO, TMO, D (each of these): 1833 MB<br />
<br />
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!!!</div>import>Am592