# Problem in the final step for 200 ns

**URL:** <https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047>\
**Category:** User discussions\
**Tags:** mdp-parameters, mdrun, simulation-setup\
**Created:** [March 26, 2023, 7:57am UTC](https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047 "2023-03-26T07:57:58Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Sayan](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Sayan](https://gromacs.bioexcel.eu/u/Sayan)\
**Post date:** [March 26, 2023, 7:57am UTC](https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047/1 "2023-03-26T07:57:58Z")

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GROMACS version:  
GROMACS modification: Yes/No  
Here post your question After setting up the md.mdp file for 200 ns i checked the log file I saw it is only for 20 ns but the steps r ok

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**Author:** ![Sayan](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Sayan](https://gromacs.bioexcel.eu/u/Sayan)\
**Post date:** [March 26, 2023, 2:48pm UTC](https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047/2 "2023-03-26T14:48:21Z")

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![IMG20230326182747](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/7/72c3e020875950aa40f6501c26d2d1831803659c.jpeg)  
This what I am getting when I am setting it for 200 ns

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**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [March 26, 2023, 5:07pm UTC](https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047/3 "2023-03-26T17:07:39Z")

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If `mdrun` is exiting normally after 20 ns, that probably means you just left off a zero in setting the number of steps for the run, so you got 20 ns instead of 200 ns.

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**Author:** ![Sayan](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Sayan](https://gromacs.bioexcel.eu/u/Sayan)\
**Post date:** [March 26, 2023, 5:27pm UTC](https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047/5 "2023-03-26T17:27:43Z")

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There should be five zeros right

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<div class="post-metadata">

**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [March 26, 2023, 5:41pm UTC](https://gromacs.bioexcel.eu/t/problem-in-the-final-step-for-200-ns/6047/6 "2023-03-26T17:41:04Z")

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`mdrun` says you specified 10000000 steps.

10000000 steps \* 0.002 ps/step = 20000 ps (20 ns) ← what you did  
100000000 steps \* 0.002 ps/step = 200000 ps (200 ns) ← what you wanted