---
name: "gmx-mk_angndx"
section: "1"
platform: "linux"
package: "gromacs-data"
version: "2025.2-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/gmx-mk_angndx"
---

# gmx-mk\_angndx(1)

Generate index files for 'gmx angle'

## NAME

gmx-mk\_angndx - Generate index files for 'gmx angle'

## SYNOPSIS

```
gmx mk_angndx [-s [<.tpr>]] [-n [<.ndx>]] [-type <enum>] [-[no]hyd]
             [-hq <real>]
```

## DESCRIPTION

**gmx mk\_angndx** makes an index file for calculation of angle distributions etc. It uses a run input file (.tpx) for the definitions of the angles, dihedrals etc.

## OPTIONS

Options to specify input files:

- **-s \[\<.tpr\>\] (topol.tpr)**

  Portable xdr run input file

Options to specify output files:

- **-n \[\<.ndx\>\] (angle.ndx)**

  Index file

Other options:

- **-type \<enum\> (angle)**

  Type of angle: angle, dihedral, improper, ryckaert-bellemans

- **-\[no\]hyd (yes)**

  Include angles with atoms with mass \< 1.5

- **-hq \<real\> (-1)**

  Ignore angles with atoms with mass \< 1.5 and magnitude of their charge less than this value

## SEE ALSO

**[gmx(1)](/gmx/1.md)**

More information about GROMACS is available at \<*http://www.gromacs.org/*\>.

## COPYRIGHT

2025, GROMACS development team