comodo-sfilter v3.2.3¶

Mercurial revision 5770:c90c3015e72d | 2026-05-22

Description¶

comodo-sfilter is a tool that duplicates the functionality of comodo-filter for scalar fields. It performs DF-II IIR filtering on input files. The tool takes one or more files as input and applies the specified filtering operations.

Usage¶

comodo-sfilter file1 [file2 ...] [OPTIONS]

Options¶

Option	Description
`-h`, `--help`	Display help and exit.
`--control <file>`	Path to a file containing control points. The file must be in ASCII format: the first line specifies the number of control points, followed by their coordinates (`longitude latitude [layer]`).
`–nodal=[yes	no]`
`-c <convention>`	Currently without effect. Specify a convention (reserved for future use).
`-l <file>`	Path to a file containing a list of input files. This list overrides any files provided as command-line arguments.
`-g <file>`	Path to the grid file.
`-p <prefix>`	Output prefix. Can be a folder path (e.g., `/output/`). Recommended: Use a different hard drive for filtering to improve performance.
`-s <date>`	Start date for filtering in `dd/mm/yyyy` format.
`-f <date>`	End date for filtering in `dd/mm/yyyy` format.
`-v <var1> [var2 ...]`	List of variables to filter.

Examples¶

Basic Filtering¶

Filter variables ssh and tem for files listed in files.list:

comodo-sfilter -l files.list -v ssh tem

Filtering with Start and End Dates¶

Filter variable ssh for files between 01/01/2020 and 31/12/2020:

comodo-sfilter -s 01/01/2020 -f 31/12/2020 -v ssh file1.nc file2.nc

Filtering with Control Points¶

Filter variable sal using a grid file and control points:

comodo-sfilter -g grid.nc --control control_points.dat -v sal file1.nc

Filtering with Output Prefix¶

Filter variable XE and save output to a specific directory:

comodo-sfilter -p /output/filtered/ -v XE file1.nc

Disable Nodal Corrections¶

Filter variable ssh without nodal corrections:

comodo-sfilter --nodal=no -v ssh file1.nc

Environment Variables¶

comodo-sfilter uses OpenMP (version 201511) for parallelization. The following environment variables can be used to control its behavior:

Variable	Description
`OMP_NUM_THREADS`	Number of threads to use.
`OMP_SCHEDULE`	Runtime schedule type and chunk size.
`OMP_DYNAMIC`	Enable or disable dynamic thread adjustment.
`OMP_NESTED`	Enable or disable nested parallelism.

Example:

OMP_NUM_THREADS=6 comodo-sfilter -l files.list -v ssh

Note: If running on a machine with high CPU load, limit the number of threads to the number of free CPUs to avoid performance degradation.

Notes¶

Input Files:

Must be comodo-compliant NetCDF files.
The tool processes scalar fields only.

Output:

Filtered files are saved with the specified prefix (-p).
If no prefix is provided, output is saved in the current directory.

Performance:

For large datasets, use -p to output to a different hard drive to avoid I/O bottlenecks.
Adjust OMP_NUM_THREADS based on available CPU resources.

Control Points:

The control points file must be in ASCII format, with the first line specifying the number of points, followed by their coordinates (longitude latitude [layer]).

Date Format:

Dates must be provided in dd/mm/yyyy format for -s and -f options.