# SD and BD integrator

**URL:** <https://gromacs.bioexcel.eu/t/sd-and-bd-integrator/1211>\
**Category:** User discussions\
**Created:** [December 7, 2020, 10:54am UTC](https://gromacs.bioexcel.eu/t/sd-and-bd-integrator/1211 "2020-12-07T10:54:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![palash](https://avatars.discourse-cdn.com/v4/letter/p/cdc98d/32.png) [@palash](https://gromacs.bioexcel.eu/u/palash)\
**Post date:** [December 7, 2020, 10:54am UTC](https://gromacs.bioexcel.eu/t/sd-and-bd-integrator/1211/1 "2020-12-07T10:54:16Z")

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GROMACS version:gmx-5.0.6  
GROMACS modification: Yes/No  
Here post your question  
Which source file contains the SD and BD integrator? , I want to modify them according to my project.

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**Author:** ![cblau](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/cblau/32/5_2.png) [@cblau](https://gromacs.bioexcel.eu/u/cblau)\
**Post date:** [December 7, 2020, 1:48pm UTC](https://gromacs.bioexcel.eu/t/sd-and-bd-integrator/1211/2 "2020-12-07T13:48:27Z")

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Hi Palash,

have a look at `update.cpp` and `do_update_bd`.

I suggest you use the currrent GROMACS master branch to start developing at

> **[GROMACS / GROMACS](https://gitlab.com/gromacs/gromacs)**
>
> The GROMACS molecular simulation toolkit.

Apart from the old code in the file that I just pointed you to, there is a new, yet unfinished “modular simulator framework” that aims at making changes to this type of machinery much easier - contact Pascal Merz at

> **[Pascal Merz](https://www.colorado.edu/lab/shirtsgroup/pascal-merz)**
>
> Education: Ph.D.

for more information.