Hi,
I did some more research and found that the issue is hardware dependent.
I tried the same input file on two different hardwares:
(A) model name : Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz
(B) model name : Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz
I now have an example input file that works on (A) but not on (B).
I also have a different examples file that works on (B) but not on (A). Both convergence failures are reproducible on the corresponding hardware.
Does this help to pinpoint what the issue could be?
I also read this post:
Could this be related?
The version of psi four we are using contains the patch mentioned. However I’m wondering, if the same problem with near zero values in not exactly an relation could happen in other places inside the code.