function smooth

Smooths X by multiplying with a gaussian of width FWHM in fourier space. The total flux is kept constant. This is equivalent to reass(fft(fft(X)*fft(gauss(naxis1(X)/2+1,naxis2(X)/2+1,FWHM))))

Syntax
result = smooth(X, FWHM)

Arguments
X:   A matrix.
FWHM:   The full width at half maximum of the gaussian used for smoothing.