ZIP_COMPRESSION_LEVEL

ZIP_COMPRESSION_LEVEL sets the compression level applied to ZIP archives storing the tensor and delta-amplitude files.

Default: 2

Allowed values: Integer values 0–9

Syntax:

ZIP_COMPRESSION_LEVEL = 5 ! use compression level 5
COMPRESSION_LEVEL = 5     ! allowed synonym
COMPRESSION = 5           ! allowed synonym

ZIP_COMPRESSION_LEVEL = 0 ! do not compress files

The compression level is a trade-off between file size and compression time. Higher compression levels reduce the size of stored tensor and delta-amplitude files but ViPErLEED will take longer to create the archives. You may want to tweak this parameter if you have limited disk space available or if you are working with large unit cells where compression takes a significant amount of time.

If ZIP_COMPRESSION_LEVEL is set to 0, files will be stored in uncompressed archives. Compression time will be almost negligible, but the files will be much larger.

../../../_images/zip_compression_levels_plot.png — Fig. 23 Benchmark results for a ~250 MB tensor file: Compressed file size and compression time vs. compression level. Average over 10 repetitions.

ViPErLEED uses the Python zipfile module for creating ZIP archives and passes the value set for ZIP_COMPRESSION_LEVEL via the compresslevel parameter.