[Pw_forum] problem with el-ph calculation: lambda.x run

[mousumi uk]

Hello All,

We encounter some problem while trying to calculate el-ph coupling
calculation and getting T_c with QE 4.3.2 (checked other versions as
well).

The system is simple graphene.
Till 6th step in example07, things look okay (at least the output
files look similar to that of Al case, as in the example). However
trying to get the T_c at the last step, we get error.

Could you please advice, how to get rid of this problem? regards,
Mousumi, Kaloni.

(i) If we try to calculate T_c at more than 1 k-point, we get error
like  following:

[kalonitp at kw2600:~/QE1/espresso-4.3.2/examples/example07/results]$lambda.x
< lambda.in
forrtl: No such file or directory
forrtl: severe (29): file not found, unit 4, file
/home/kalonitp/QE1/espresso-4.3.2/examples/example07/results/fort.4
Image              PC                Routine            Line
Source
lambda.x           00000000004A565D  Unknown               Unknown  Unknown
lambda.x           00000000004A4165  Unknown               Unknown  Unknown
lambda.x           0000000000452B49  Unknown               Unknown  Unknown
lambda.x           0000000000412ABF  Unknown               Unknown  Unknown
lambda.x           00000000004122F2  Unknown               Unknown  Unknown
lambda.x           0000000000430EE5  Unknown               Unknown  Unknown
lambda.x           000000000040A374  MAIN__                     78  lambda.f90
lambda.x           0000000000409EBC  Unknown               Unknown  Unknown
libc.so.6          000000328261EA4D  Unknown               Unknown  Unknown
lambda.x           0000000000409DB9  Unknown               Unknown  Unknown

(ii) Trying to calculate T_c only at Gamma point, we get the following problem.

lambda.x < lambda.in
     lambda = 0.000000 (       NaN)  <log w>=      NaNK  N(Ef)=
0.000000 at degauss=0.005
     lambda = 0.000000 (       NaN)  <log w>=      NaNK  N(Ef)=
0.000000 at degauss=0.010
     lambda =-0.001000 (       NaN)  <log w>=      NaNK  N(Ef)=
0.000022 at degauss=0.015
     lambda =-0.098800 (       NaN)  <log w>=      NaNK  N(Ef)=
0.002334 at degauss=0.020
     lambda =-0.771700 (       NaN)  <log w>=      NaNK  N(Ef)=
0.018374 at degauss=0.025
     lambda =-2.183000 (       NaN)  <log w>=      NaNK  N(Ef)=
0.053865 at degauss=0.030
     lambda =-3.817500 (       NaN)  <log w>=      NaNK  N(Ef)=
0.101240 at degauss=0.035
     lambda =-5.192300 (       NaN)  <log w>=      NaNK  N(Ef)=
0.151853 at degauss=0.040
     lambda =-6.150400 (       NaN)  <log w>=      NaNK  N(Ef)=
0.200803 at degauss=0.045
     lambda =-6.717700 (       NaN)  <log w>=      NaNK  N(Ef)=
0.246560 at degauss=0.050
lambda        omega_log          T_c
   0.00000           NaN                NaN
   0.00000           NaN                NaN
  -0.00100           NaN                NaN
  -0.09880           NaN                NaN
  -0.77170           NaN                NaN
  -2.18300           NaN                NaN
  -3.81750           NaN                NaN
  -5.19230           NaN                NaN
  -6.15040           NaN                NaN
  -6.71770           NaN                NaN