Changing parameters in RPA
Posted: Sun Mar 05, 2023 5:04 pm
Dear users of this forum,
While performing RPA-related calculations using VASP, I came across several questions and wondered if you could help me.
Firstly, I wanted to understand why it is suggested that ENCUTGW is best when it is 2/3 of ENCUT. I wondered if this was because it strikes a balance between accuracy and computational cost for extrapolation. If this is the case, I was curious to know if it is still possible to obtain good results using ENCUT = ENCUTGW, even if the extrapolation calculation is a bit expensive.
Secondly, I have a question about running the calculation at low ENCUT while holding NBANDS and ENCUT through WAVECAR generated at high ENCUT (ISTART = 1). I have attached the inputs and outputs related to this calculation, but I had to exclude the WAVECAR file due to its large size. Would this cause an orbital orthonormalization error? Also, I was curious to know why the GENERATE_KPOINTS_TRANS process causes a bug on some systems and what circumstances usually lead to this phenomenon. Why can add one molecule alternate between errors and bugs?
Finally, I encountered a similar error when calculating RPA using high ENCUTGW while maintaining NBANDS and ENCUT through WAVECAR generated at low ENCUT.
Thank you for taking the time to read this post, and I appreciate any insights you can offer.
Best regards,
sc_han
While performing RPA-related calculations using VASP, I came across several questions and wondered if you could help me.
Firstly, I wanted to understand why it is suggested that ENCUTGW is best when it is 2/3 of ENCUT. I wondered if this was because it strikes a balance between accuracy and computational cost for extrapolation. If this is the case, I was curious to know if it is still possible to obtain good results using ENCUT = ENCUTGW, even if the extrapolation calculation is a bit expensive.
Secondly, I have a question about running the calculation at low ENCUT while holding NBANDS and ENCUT through WAVECAR generated at high ENCUT (ISTART = 1). I have attached the inputs and outputs related to this calculation, but I had to exclude the WAVECAR file due to its large size. Would this cause an orbital orthonormalization error? Also, I was curious to know why the GENERATE_KPOINTS_TRANS process causes a bug on some systems and what circumstances usually lead to this phenomenon. Why can add one molecule alternate between errors and bugs?
Finally, I encountered a similar error when calculating RPA using high ENCUTGW while maintaining NBANDS and ENCUT through WAVECAR generated at low ENCUT.
Thank you for taking the time to read this post, and I appreciate any insights you can offer.
Best regards,
sc_han