search

HyQD / coupled-cluster

Upstream coupled cluster code
MIT License
3 stars 3 forks source link

Erroneous Q-space equations #51

Open halvarsu opened 4 years ago

halvarsu commented 4 years ago

The Q-space equations in OATDCC are based on the anti-symmetrized u-matrix elements, however Kvaal's 2012-article states that these should be derived from the non-anti-symmetrized matrix elements, as seen in eq 33 or more explicitly on page 5 of the appendix.

It seems like this requires us to also store and update a version of the non-anti-symmetrized matrix elements, which is a shame in computational terms. I have managed to implement a fix in the my hacked DVR-basis-oatdcc, which already stores u-matrix elements in their original form and anti-symmetrizes when needed (due to the sparse 2d representation). However, I find it an extremely open question how to best implement this in the "official" OATDCC.

haakoek commented 4 years ago

One possibility is to contact Takeshi on mail and ask him how they do it: sato@atto.t.u-tokyo.ac.jp