[gmx-users] bug in demux.pl

Swarnendu Tripathi stripat1 at kent.edu
Wed Aug 3 00:19:46 CEST 2011


Hi,

I am not sure if this problem has been solved or discussed before.

I found that when I use the demux.pl script it does not read the actual time
from the .log file. This is for gromacs-4.0.7.

These are few lines from one of the .log file for my replica exchnage
simulation. For example in the second line below the actual time is
"1199992.0" in ps. However, the demux.pl script reads the time from the
"Replica exchange" phrase as "1.19999e+06". Same thing repeats in the
following steps which is not right.
==================================================================
            Step           Time         Lambda
      299998000   1199992.12500        0.00000

   Energies (kJ/mol)
        G96Bond       G96Angle    Proper Dih.  Improper Dih.          LJ-14
    1.58180e+03    1.49412e+03    7.67393e+02    3.69239e+02   -2.78302e+02
     Coulomb-14        LJ (SR)   Coulomb (SR)      Potential    Kinetic En.
   -2.39467e+00    8.01055e+01   -1.05400e+01    4.00143e+03    4.06353e+03
   Total Energy    Temperature Pressure (bar)
    8.06496e+03    4.51898e+02    0.00000e+00

Replica exchange at step 299998000 time 1.19999e+06
Repl 7 <-> 8  dE =  1.607e-01
Repl ex  0    1 x  2    3 x  4    5 x  6    7 x  8    9 x 10   11 x 12   13
x 14   15 x 16   17 x 18   19 x 20   21 x 22   23
Repl pr        .79       1.0       1.0       .85       1.0       .98
.98       .90       1.0       1.0       .90

           Step           Time         Lambda
      299999000   1199996.12500        0.00000

   Energies (kJ/mol)
        G96Bond       G96Angle    Proper Dih.  Improper Dih.          LJ-14
    1.42588e+03    1.43257e+03    7.64199e+02    3.39804e+02   -7.50646e+02
     Coulomb-14        LJ (SR)   Coulomb (SR)      Potential    Kinetic En.
   -2.96172e+00    9.62908e+01   -1.95152e+01    3.28563e+03    4.16581e+03
   Total Energy    Temperature Pressure (bar)
    7.45144e+03    4.63272e+02    0.00000e+00

Replica exchange at step 299999000 time 1.2e+06
Repl 8 <-> 9  dE =  2.023e-01
Repl ex  0 x  1    2 x  3    4 x  5    6 x  7    8    9   10 x 11   12 x
13   14 x 15   16 x 17   18 x 19   20 x 21   22 x 23
Repl pr   1.0       .98       .66       1.0       .82       1.0
.92       .93       .79       1.0       .96       1.0

========================================================================================

As a result my "replica_index.xvg" looks like this which is not right.
========================================================================================
1.19996e+06   11    9   22   12   10   21    5   23   17    7   19    8
3    1   15    0   13    6   20   14    4    2   16   18
1.19996e+06    9   11   12   22   21   10   23    5    7   17    8   19
1    3    0   15    6   13   14   20    2    4   18   16
1.19997e+06    9   12   11   21   22   23   10    7    5    8   17    1
19    0    3    6   15   14   13    2   20   18    4   16
1.19997e+06   12    9   21   11   23   22    7   10    8    5    1   17
0   19    6    3   14   15    2   13   20   18   16    4
1.19998e+06   12   21    9   23   11   22    7    8   10    5    1    0
17    6   19   14    3    2   15   13   20   16   18    4
1.19998e+06   21   12   23    9   22   11    8    7   10    5    0    1
6   17   19   14    2    3   13   15   16   20    4   18
1.19998e+06   21   23   12   22    9    8   11   10    7    5    0    6
1   19   17    2   14   13    3   16   15    4   20   18
1.19999e+06   23   21   22   12    9    8   10   11    5    7    6    0
19    1    2   17   13   14   16    3    4   15   18   20
1.19999e+06   23   22   21    9   12   10    8    5   11    6    7   19
0    2    1   13   17   16   14    4    3   18   15   20
1.2e+06    22   23    9   21   10   12    5    8   11    6   19    7    2
0   13    1   16   17    4   14   18    3   20   15
=========================================================================================

Due to the problem in precision, time step repeats. The demux.pl script
should read the actual time from the previous step in the .log file.

-Swarnendu
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