TEST/diff_fcn.c File Reference

Compare two sets of function values. More...

#include "../libftsh.h"

Functions
void	main (int argc, char *argv[])

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Detailed Description

Compare two sets of function values.

This program compares two sets of function values as used in a spherical harmonic transform. It outputs the \(L^2\) error between them.

For instance we can compare function values after two different versions of the transform.

We do not use the quadrature weight, so this is only a rough estimate of the proper error.

Usage: call this routine with 4 command-line arguments: numpts band_limit fcn_file_1 fcn_file_2

• numpts -- the number of latitude points
• band_limit -- The restriction on the degree of the expansion (n in \(P^m_n\) notation).
• fcn_file_1 -- the file from which to read the first set of fcn values. We read numpts*(2*band_limit-1) REALs.
• fcn_file_2 -- the file from which to read the second set of fcn values. We read numpts*(2*band_limit-1) REALs.