scale_psf and shift are basically the same routine. Shift is given a 5x5 array; does a spline fit; and spits out values for different shifts.
scale_psf reads a 7x7 array from a 9x9, then does a spline fit, etc.
scale_psf runs. Shift gives an error from subroutine splint.

Bad xa input to routine splint meaning the xa's are supposed to be distinct.

After about two days of working on this, I'm stumped.