NHelicon - Non-stationary helix convolution and deconvolution

Helicon < in.H filt= adj=0 div=0 > out.H

Applies helix convolution (polynomial multiplication) or deconvolution (polynomial division). One is the exact inverse of the other. Watch for helical boundary conditions.

from history	integer array	n	reads n1 , n2 , n3 , ...
from par	filename	filt	helix filter file
	integer	adj =0	apply adjoint (backward) filtering
	integer	div =0	apply inverse recursive filtering (polynomial division)
from aux (filt)	integer array	h	helix grid (can be h1 , h2 , ...)
	integer array	lag =1,...,n1	comma separated list of filter lags
	real	a0 =1	zero-lag filter coefficient

Modules: nhelicon.lop , npolydiv.lop , nhelix.r90 , helix.r90 , regrid.r90