# Force constants IO¶

Hiphive provides read and write functionality for force constants in a few different formats. Currently the following formats are supported.

## GPUMD¶

We also support functionality for writing force constants and other relevant files to GPUMD format. GPUMD is a packages that allows one to calculate for example thermal conductivities using molecular dynamics (MD) simulations both via the Green-Kubo and the homogenenous non-equilibrium MD approach.

## Conversion betweeen ShengBTE and phono3py¶

The following snippet demonstrates the conversion from phono3py to ShengBTE:

from hiphive import ForceConstants

fcs.write_to_shengBTE('FORCECONSTANTS_3rd', prim)


Conversion in the opposite direction is achieved as follows:

from hiphive import ForceConstants