# A question about gen\_seed in the log file
**URL:** https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033
**Category:** User discussions
**Tags:** mdp-parameters, mdrun, simulation-setup
**Created:** [April 17, 2022, 4:33am UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033 "2022-04-17T04:33:27Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@liuwq](https://gromacs.bioexcel.eu/u/liuwq)
#### Post date: [April 17, 2022, 4:33am UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/1 "2022-04-17T04:33:27Z")
GROMACS version: 2018.8
Hello,
I am using the COM pulling options to do the pull simulation of my system. I want to do several identical pull simulations from the same configuration but with different initial velocities. In my understanding, these are identical simulations of different starting microscopic states. In this way, I can improve the statistics of my output data.
So, I am trying to explicitly set different `gen-seed` to generate different initial velocities of the same configuration. But I am a little confused that I checked the log file, in the section **input parameters** , I only found that the line of `ld-seed` is different from my different simulations. I did not find a line that contains `gen-seed` in the log files. As a result, I am not sure whether my setting of `gen-seed` is effective in my simulation. How can I check whether a different `gen-seed` has been successfully set?
It seems `ld-seed` is a different thing, but I am not sure what is the effect of this parameter on my simulation, if a little more explanation could be given for this parameter, that would be much appreciated!
Thanks very much in advance!
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### Author:  [@Yogeshb](https://gromacs.bioexcel.eu/u/Yogeshb)
#### Post date: [April 18, 2022, 2:16am UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/2 "2022-04-18T02:16:30Z")
Check once with generated mdp file whether u face the problem.
Use option _gmx grompp -po_ option to get mdp file.
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### Author:  [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)
#### Post date: [April 18, 2022, 2:39am UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/3 "2022-04-18T02:39:45Z")
> [@liuwq](#):
>
> How can I check whether a different `gen-seed` has been successfully set?
You can obtain its value from `gmx dump` or the actual velocities themselves. The velocities in each `.tpr` file will be different.
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### Author:  [@liuwq](https://gromacs.bioexcel.eu/u/liuwq)
#### Post date: [April 20, 2022, 8:27pm UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/4 "2022-04-20T20:27:02Z")
Thank you very much for the reply!
The default output .mdp file of `gmx grompp` seems to be mdout.mdp. I found that `gen_seed` is included in the mdout.mdp file. Do I understand correctly what you mean?
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### Author:  [@liuwq](https://gromacs.bioexcel.eu/u/liuwq)
#### Post date: [April 20, 2022, 8:34pm UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/5 "2022-04-20T20:34:17Z")
Thank you very much for the reply!
Your suggestion exactly matches what I need. `gmx dump` can print the information of velocities on the screen.
After consult the doc page of `gmx dump`, one minor problem I found is that, it seems the command does not give an option to output the information to a file. I have 30000 atoms, then it becomes very hard to browser all the information, I only can view the last part of the output on my screen. Could you please give me more help?
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### Author:  [@Tijanar](https://gromacs.bioexcel.eu/u/Tijanar)
#### Post date: [September 20, 2022, 9:43am UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/6 "2022-09-20T09:43:26Z")
May be it is sloved already.
You can use, gromacs commands \> output.txt
“\>” (or “\>\>”) help to write output from screen to a file which can be used for future purposes.
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### Author:  [@liuwq](https://gromacs.bioexcel.eu/u/liuwq)
#### Post date: [September 22, 2022, 3:51pm UTC](https://gromacs.bioexcel.eu/t/a-question-about-gen-seed-in-the-log-file/4033/7 "2022-09-22T15:51:22Z")
Hi, thank you very much for the reply!
That is exactly what I need. To redirect to an output file would just solve my problem, I should have thought about this before. Thanks very much!