opt not converge and exceeding max walkers

[zhu yijie]

Dear QMCPACK developers,
I am a beginner in QMCPACK and I am trying to do a dmc calculations on my system.
1. When I try to do the opt part, the variance is always large and not converge to a small value. And the Delta Cost in the output file keeps fluctuating.
2. When I do the dmc calculations, there are many "WARNING Exceeding Max Walkers per MPI rank : 21. Ceiling is applied" in my output file, and the work is done.
Thank you for your consideration and best wishes,
Yijie Zhu

[Paul R. C. Kent]

Dear Yijie - Thanks for your patience. Can you please say some more about the system you are trying QMC on? And which systems you have previously had successful QMC runs for? Generally if the optimization has a significant problem it is not worth trying the DMC because the trial wavefunction will be too poor.

[zhu yijie]

Dear Paul 

Apologies for the delayed response. I inadvertently missed your email and only saw it now after a few days. I successfully run the example for Oxygen atom (labs/lab2_qmc_basics/oxygen_atom). We also refer to this example input when calculating our own system.  I don't know why if I add the input file in the attachment, google group shows that the length of letter exceeds. The detailed input file has been sent to your email.

Yijie Zhu