[Pw_forum] Re:error in band structure calculation

[Xinxin Yao]

Thank you for your help!
I use version 3.2 .
When calculation="nscf", I use the initial atom position of vc-relax, then I meet
the error mentioned above, and the file "data-file.xml" in the output folder is
missing. I change the atom position to the relax position, and restart. A new
error appears as follows:

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     from setup  : error #         1
     problem reading ef from file /home/disk2/work/7.05/temp/ge-mn.save
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     stopping ...

So I copy the backup "data-file.xml" to the output folder. The second error is
resolved, but the first one remains.

When calculation="bands", I get the same results.

My question is:
1)Why does the program delete the file "data-file.xml" when doing band structure
calculation? I have to copy the backup file into the output folder after each
calculation.

2)Whether I use "bands" or "nscf", and whether I use the initial atom position or
the relax one when doing band calculation, I always meet the error "starting and
expected charges differ". I delete the file "charge-density.xml" manually, and get
message as follows:

     Check: negative/imaginary core charge=   -0.000025    0.000000
     Cannot read rho : file not found

     Initial potential from superposition of free atoms
     Check: negative starting charge=(component1):  -12.900563
     Check: negative starting charge=(component2):  -12.927055

     negative rho (up, down):  0.129E+02 0.129E+02
     Starting wfc are atomic

Then the calculation can finish. This is the only way I could use to finish the
band calculation now. Is that right, or could you give me any other helpful
suggestions?

3)During my use, I find the prefix = 'something' and prefix = something are equal.
I think we don't have to distinguish them exactly. 

Thank you again!
Xinxin Yao