Sir i want to ask 1 question on dump file how to print coordinate of particle in dump file without append. i want to print configuration file every step but without append, can it is possible in lammps?
Example: suppose my dump file name is dump.out. 1st it will print in dump.out file 1st step configuration,in 2nd step again it will print in dump.out file but it will erase previous step configuration file. that i want, is it possible in lammps.? if yes then how? actually i don’t want to save configuration file, i have written small code, in which required coordinate of particle. if i will all configuration file from 1 to 5 million step then it will take so much space.
In dump_modify i have seen 1 keyword “append” but it is not working. About dump_modify : keyword append he append keyword applies to all dump styles except cfg and xtc and dcd. It also applies only to text output files, not to binary or gzipped or image/movie files. If specified as yes, then dump snapshots are appended to the end of an existing dump file. If specified as no, then a new dump file will be created which will overwrite an existing file with the same name. This keyword can only take effect if the dump_modify command is used after the dump command, but before the first command that causes dump snapshots to be output, e.g. a run or minimize command. Once the dump file has been opened, this keyword has no further effect.
Example: suppose my dump file name is dump.out. 1st it will print in dump.out file 1st step configuration,in 2nd step again > it will print in dump.out file but it will erase previous step configuration file. that i want, is it possible in lammps.? if yes then > how?
No, there is no option currently in LAMMPS that will do this. No one has ever asked for it. There are lots
of workarounds. You could use a dump file name like tmp.dump.* in which case you will get one file per
snapshot. Run a script as your simulation is running to delete all old dump files periodically, so you will
only have the last one (until new ones are written). Or if you are running for hours to get 5 million steps,
then why not just dump every million steps, so that you have a much smaller dump file that includes
a recent step?
Purpose of doing this to make block average of structure. i need configuration file from 1 to 2 lake step every step and make it block avg, continue up to 40 million. sir is there option to modify code based on this so i will try to do this .
Now you email makes it sound like you want all the snapshots for 40 million
steps so you can do block averaging. I read your previous email
to mean you only wanted the last timestep, and have it continously
overwrite previous steps. So i don’t know what you’re asking.
You can look at fix ave/atom if you want to do time averaging of
atom properties within LAMMPS, and output them to a dump file.