error with fix langevin

Hi
I got the following error when running Lammps version 7 dec 2018 on windows.

ERROR: Expected floating point parameter in input script or data file (…/fix_langevin.cpp:71)
Last command: fix 2 mobile langevin temp 373.0 373.0 10. 587283

I undestand when looking at fix_langevin.cpp that l71 is concerned by tstart, which I expect to be the starting temperature in the fix langevin command.
But in fix langevin command I wrote, all 3 three first parmeters are floating and the seed is positive integer.
Or is the error related to a previous command ?

The overall sequence in the script is
fix 1 He nvt temp 373.0 373.0 10.
fix 2 mobile langevin temp 373.0 373.0 10. 587283
fix 3 mobile nve
fix 4 He deposit 10 4 2000 78913542 region He_reg vz -0.0005 -0.0005 units box # Attention: A/fs units !!!
fix 5 He wall/reflect zhi EDGE

This is adapted from the deposit.molecule script available on the lammps web site. This works in my other similar program

Thanks a lot for help
and sorry in advance if it is a trivial issue.
Best regards
pascal

Hi
I got the following error when running Lammps version 7 dec 2018 on windows.

ERROR: Expected floating point parameter in input script or data file (../fix_langevin.cpp:71)
Last command: fix 2 mobile langevin temp 373.0 373.0 10. 587283

I undestand when looking at fix_langevin.cpp that l71 is concerned by tstart, which I expect to be the starting temperature in the fix langevin command.
But in fix langevin command I wrote, all 3 three first parmeters are floating and the seed is positive integer.
Or is the error related to a previous command ?

fix langevin does not have a "temp" keyword. that is the one that is
causing the issue, since it is most certainly not a floating point
number. :wink:

axel.

Thanks a lot Axel
It is time I change my glasses for correct reading of the manual !!
Best regards
Pascal

Hi
I got the following error when running Lammps version 7 dec 2018 on windows.

ERROR: Expected floating point parameter in input script or data file (../fix_langevin.cpp:71)
Last command: fix 2 mobile langevin temp 373.0 373.0 10. 587283

I undestand when looking at fix_langevin.cpp that l71 is concerned by tstart, which I expect to be the starting temperature in the fix langevin command.
But in fix langevin command I wrote, all 3 three first parmeters are floating and the seed is positive integer.
Or is the error related to a previous command ?

fix langevin does not have a "temp" keyword. that is the one that is
causing the issue, since it is most certainly not a floating point
number. :wink:

axel.

Thanks a lot Axel
It is time I change my glasses for correct reading of the manual !!

i am thinking to make the error message a bit more specific, e.g. like this:

ERROR: Expected floating point parameter instead of 'temp' in input
script or data file (src/fix_langevin.cpp:71)
Last command: fix 2 all langevin temp 373.0 373.0 10. 587283

that should make it easier to spot the reason for the failure. it is a
bit unfortunate, that these flags are not consistent across thermostat
styles.

axel.

Thanks Axel for the suggestion.
I think the reason comes from my previous nvt calculations where fix nvt requires a temp keyword.
Thanks a lot for the time spent.
Best regards
Pascal

Thanks a lot Axel
It is time I change my glasses for correct reading of the manual !!

i am thinking to make the error message a bit more specific, e.g. like this:

ERROR: Expected floating point parameter instead of 'temp' in input
script or data file (src/fix_langevin.cpp:71)
Last command: fix 2 all langevin temp 373.0 373.0 10. 587283

that should make it easier to spot the reason for the failure. it is a
bit unfortunate, that these flags are not consistent across thermostat
styles.

axel.

updated code is now in a pending pull request on GitHub and should be
included in the next patch.
https://github.com/lammps/lammps/pull/1258

this should also make it easier to detect when a variable reference
(like v_name) is used as an argument, where this is not supported.
This is another case, besides having to (not) use temp, where the
generic error message makes it annoyingly laborious to spot this kind
of error, if you haven't memorized all 2500+ pages of the LAMMPS
manual.

axel.

Thanks again Axel

Pascal Brault
DR CNRS
GREMI UMR7344
CNRS-Université d’Orléans
+33631498790

updated code is now in a pending pull request on GitHub and should be
included in the next patch.
https://github.com/lammps/lammps/pull/1258

this should also make it easier to detect when a variable reference
(like v_name) is used as an argument, where this is not supported.
This is another case, besides having to (not) use temp, where the
generic error message makes it annoyingly laborious to spot this kind
of error, if you haven't memorized all 2500+ pages of the LAMMPS
manual.

axel.