Yambo Community Forum

Posted: **Wed Nov 01, 2023 3:52 pm**

Hello,

I noticed that during a GW calculation the report file shows a different input value for NGsBlkXp than the actual input file. I attached the input and report for a fast test calculation for diamond. In the input file I set NGsBlkXp = 4 Ry. The end of the report states NGsBlkXp = 6 Ry. Why does this happen?

Best regards,
Max

Posted: **Thu Nov 02, 2023 9:27 am**

Dear Max,

this is probably due to the fact that Yambo includes extra G vectors to close the shells. In your case, I can see that you are using a very small number of Gvectors. Here, 4 Ry (2Ha) is in between the third and fourth shell of Gvectors. Yambo include all the gvectors to close the fourth shells (27 gvectors). These can be seen in the report file.
To have a better control you can assign the matrix size in terms of RL (number of reciprocal lattice vectors) or in mHa, mRy.

Code: Select all

G-vecs. in first 23 shells:  [ Number ]
     1    9   15   27   51   59   65   89  113                            
    137   169   181   229   259   283   307   331   339
    387   411   459   531   537
  ...                
  Shell energy in first 23 shells:  [ mHa ]
    0.00000      1307.89      1743.85      3487.71      4795.60      5231.56      6975.42      8283.31      8719.27
    10463.1      11771.0      13950.8      15258.7      15694.7      17438.5      18746.4      19182.4      20926.3
    22234.1      22670.1      24414.0      25721.8      27901.7

Best,

Daniele

Yambo Community Forum

Different NGsBlkXp in input and report

Different NGsBlkXp in input and report

Re: Different NGsBlkXp in input and report