# REMD: "topol.tpr" required but I do not have it **URL:** \ **Category:** User discussions\ **Created:** [January 12, 2021, 12:16pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425 "2021-01-12T12:16:29Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![lanselibai](https://avatars.discourse-cdn.com/v4/letter/l/e9c0ed/32.png) [@lanselibai](https://gromacs.bioexcel.eu/u/lanselibai)\ **Post date:** [January 12, 2021, 12:16pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425/1 "2021-01-12T12:16:29Z")
GROMACS version:2019 GROMACS modification: No Here post your question I am running REMD. I use the protocol of Justin’s lysozyme to prepare all the EM/NVT/NPT at different temperature folders, and generate individual `md_0_1.tpr` files. Then I use command `gerun mdrun_mpi -v -multidir 1_338.15 2_339.2 3_340.26 4_341.31 5_342.37 6_343.44 7_344.5 8_345.57 9_346.64 10_347.72 11_348.79 12_349.87 13_350.95 14_352.04 15_353.12 16_353.15 -replex 100` to run the REMD, but was told ``` File input/output error: topol.tpr ``` But `topol.tpr` files are not generated during the EM/NVT/NPT steps. Also, which files are required to run the REMD? For a normal MD, only the `tpr` file is required. ---
**Author:** ![alevilla](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/alevilla/32/439_2.png) [@alevilla](https://gromacs.bioexcel.eu/u/alevilla)\ **Post date:** [January 12, 2021, 1:28pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425/2 "2021-01-12T13:28:05Z")
Hi, the problem is that mdrun do not find the tpr files. The option -multidir requires that you provide a set of `n` directories for the `n` simulations, place all the relevant input files in those directories (e.g. named `topol.tpr` ) see more [Useful mdrun features — GROMACS 2020.5 documentation](https://manual.gromacs.org/current/user-guide/mdrun-features.html?highlight=replica) Best regards Alessandra ---
**Author:** ![lanselibai](https://avatars.discourse-cdn.com/v4/letter/l/e9c0ed/32.png) [@lanselibai](https://gromacs.bioexcel.eu/u/lanselibai)\ **Post date:** [January 12, 2021, 2:06pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425/3 "2021-01-12T14:06:01Z")
Hi Alessandra, thank you! I do have a `md_0_1.tpr` file in each temperature folder. It is just does not have the name of `topol.tpr`. Does it mean I just need to change the names of all the `md_0_1.tpr` into `topol.tpr`? How do I know the name of the `tpr` file should be `topol.tpr`? What other files are needed? I have already prepared multiple temperature folders, and copied each` tpr` file to each folder. ---
**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:** [January 12, 2021, 2:17pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425/4 "2021-01-12T14:17:10Z")
You didn’t specify any file names in your command, so `mdrun` looked for the default input to `-s`, which is `topol.tpr`. You can use any file names you like as long as you actually specify them, via `-s` or `-deffnm`. ---
**Author:** ![lanselibai](https://avatars.discourse-cdn.com/v4/letter/l/e9c0ed/32.png) [@lanselibai](https://gromacs.bioexcel.eu/u/lanselibai)\ **Post date:** [January 12, 2021, 2:25pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425/5 "2021-01-12T14:25:17Z")
I see, thanks. Do I also need to supply` -cpi -append` ? I am running it on our cluster, so I want to request less computational resources. But I want to submit `-hold_jid` jobs to continue from the previous check point. e.g. `gerun mdrun_mpi -v -deffnm md_0_1 -replex 100 -cpi -append -multidir 1_338.15 2_339.2 3_340.26 4_341.31 5_342.37 6_343.44 7_344.5 8_345.57 9_346.64 10_347.72 11_348.79 12_349.87 13_350.95 14_352.04 15_353.12 16_353.15` ---
**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:** [January 12, 2021, 2:48pm UTC](https://gromacs.bioexcel.eu/t/remd-topol-tpr-required-but-i-do-not-have-it/1425/6 "2021-01-12T14:48:42Z")
All relevant `mdrun` options still need to be provided. Your command simply tells `mdrun` there are multiple simulations to be performed in the listed directories, but provides nothing else. If you are doing a continuation, you need to add those options.