The interpolation function for a given dataset is stored in a
gsl_interp2d object. These are created by the following functions.
This function returns a pointer to a newly allocated interpolation object of type T for xsize grid points in the x direction and ysize grid points in the y direction.
This function initializes the interpolation object interp for the
data (xa,ya,za) where xa and ya are arrays of
the x and y grid points of size xsize and ysize
respectively, and za is an array of function values of size
xsize*ysize. The interpolation object (
not save the data arrays xa, ya, and za and only stores the
static state computed from the data. The xa and ya data arrays
are always assumed to be strictly ordered, with increasing x,y values;
the behavior for other arrangements is not defined.
This function frees the interpolation object interp.