[Pw_forum] A small bug of QE when nat >= 100, and the solution

[lfhuang]

Dear QEers:
     When I was calculating vibrational frequencies for a system with nat >= 100, I noticed a small bug of QE. The calculation steps were:
(1) pw.x for scf electronic calculation;
(2) ph.x for linear-response calculation;
(3) q2r.x for the reciprocal-to-real transformation;
Then, QE claimed that:
######################
from read_f: error # 1
wrong na read 
######################
the error message may be different at some computers, like:
#################
end of file during read ...... 
#################  
Although this error information has been reported many times on the PW_FORUM, this time, it is caused by  "nat >=100".
(1) The cause 
    When nat >=100, some lines in *.dyn[123...] file (which includes the reciprocal dynamical matrix) will be like that:
**************************************
 34 99
  0.00000113  0.00000000   -0.00000895  0.00000000    0.00000474  0.00000000
 -0.00002272  0.00000000   -0.00002000  0.00000000   -0.00001948  0.00000000
  0.00002366  0.00000000   -0.00002707  0.00000000    0.00006012  0.00000000
 34100
  0.00006484  0.00000000   -0.00000418  0.00000000   -0.00003671  0.00000000
 -0.00000097  0.00000000   -0.00000993  0.00000000    0.00001364  0.00000000
  0.00003728  0.00000000   -0.00000805  0.00000000    0.00002762  0.00000000 
************************************** 
the sencond pair of atomic indices above get close to each other. When execute q2r.x, these two numbers are read together as one number, which is the cause of the error.
 
(2) The solution
vi espresso/PH/q2r.f90
go to the Line 586, which is:
****************************
   READ(1,*) i,j  
**************************** 
change it to be
****************************
  READ(1,'(2i3)') i,j 
**************************** 
then, compile QE again. 
 
 May this could be of a little help to you.
 
Best Wishes!
Yours Sincerely
L. F. Huang 
------
======================================================================
L.F.Huang(黄良锋) DFT and phonon physics
======================================================================
Add: Research Laboratory for Computational Materials Sciences,
Instutue of Solid State Physics,the Chinese Academy of Sciences,
P.O.Box 1129, Hefei 230031, P.R.China
Tel: 86-551-5591464-326(office)
Fax: 86-551-5591434
Our group: http://theory.issp.ac.cn
======================================================================


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