Mercurial > octave-nkf
view scripts/polynomial/conv.m @ 787:c5d35bb139b6
[project @ 1994-10-11 00:34:13 by jwe]
Initial revision
author | jwe |
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date | Tue, 11 Oct 1994 00:34:39 +0000 |
parents | |
children | 3470f1e25a79 |
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function y = conv (a, b) # Convolve two vectors. # y = conv (a, b) returns a vector of length equal to length (a) + # length (b) -1. # If a and b are polynomial coefficient vectors, conv returns the # coefficients of the product polynomial. # # SEE ALSO: deconv, poly, roots, residue, polyval, polyderiv, # polyinteg # Author: # Tony Richardson # amr@mpl.ucsd.edu # June 1994 if (nargin != 2) error ("usage: conv(a,b)"); endif if (is_matrix(a) || is_matrix(b)) error("conv: both arguments must be vectors"); endif la = length (a); lb = length (b); ly = la + lb - 1; # Ensure that both vectors are row vectors. if (rows (a) > 1) a = reshape (a, 1, la); endif if (rows (b) > 1) b = reshape (b, 1, lb); endif # Use the shortest vector as the coefficent vector to filter. if (la < lb) if (ly > lb) x = [b zeros (1, ly - lb)]; else x = b; endif y = filter (a, 1, x); else if(ly > la) x = [a zeros (1, ly - la)]; else x = a; endif y = filter (b, 1, x); endif endfunction