# Extend simulation without a checkpoint file

**URL:** <https://gromacs.bioexcel.eu/t/extend-simulation-without-a-checkpoint-file/4273>\
**Category:** User discussions\
**Created:** [June 7, 2022, 9:02am UTC](https://gromacs.bioexcel.eu/t/extend-simulation-without-a-checkpoint-file/4273 "2022-06-07T09:02:49Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![di\_jin](https://avatars.discourse-cdn.com/v4/letter/d/e274bd/32.png) [@di\_jin](https://gromacs.bioexcel.eu/u/di_jin)\
**Post date:** [June 7, 2022, 9:02am UTC](https://gromacs.bioexcel.eu/t/extend-simulation-without-a-checkpoint-file/4273/1 "2022-06-07T09:02:50Z")

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GROMACS version: 2018.3  
GROMACS modification: Yes/No  
Here post your question

Is it possible to extend a simulation without a checkpoint file using only result files (.trr and .edr, xvg. etc) ?  
I know this used to be an option with older versions of convert-tpr but for some reason deprecated. I wonder if there is a replacement for this function?

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**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\
**Post date:** [June 7, 2022, 1:26pm UTC](https://gromacs.bioexcel.eu/t/extend-simulation-without-a-checkpoint-file/4273/2 "2022-06-07T13:26:12Z")

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grompp can do this for you. Set init\_step correctly and the continuation option to yes.