[clean-list] FFT and Clean

[Richard A. O'Keefe]

Siegfried Gonzi <siegfried.gonzi@kfunigraz.ac.at> wrote:
	- You should be aware that the Numerical Recipes C code is using
	one-offset (as Fortran) and not zero-offset. This is
	also accounted for when you pass the vector to the fft subroutine, then
	you have to pass it with pointer beeing
	decremented by 1. Completely mad.
	
It is also completely illegal in C.  In C you may form a pointer to
any element of an array, and also to the non-existent element just past
the end of the array (although that pointer may not be dereferenced).
It has never been legal in C to form a pointer that points _before_ an array.