## Section: Software

Keywords : multidimensional visualization, compression, hierarchical finite elements.

### calviExport library

Participants : Matthieu Haefele, Guillaume Latu.

This library contains the different algorithms which can compress a 4D function which is known on a regular grid. These algorithms have been designed to work on independent blocs of data if they share one point on their boundaries. So this library can be easily integrated into parallel
codes. For example, it has been successfully integrated into LOSS, YODA and GYSELA5D (gyrokinetic code from CEA-Cadarache). The output is a set of binary files which contain the resulting compressed function and are structured thanks to a dedicated sparse data format. Typically, we have
compressed a 32 GB particle beam distribution function (
256
^{4} grid) into a 40 MB compressed function, which represent a compression factor of 819. This data export relies on the HDF5 library
(http://www.hdfgroup.org/ ), so it is efficient and portable. Finally, these files are directly imported into the plasmaViz software for 4D visualization.