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Re: polyvalm.m
From: |
Ross A. Lippert |
Subject: |
Re: polyvalm.m |
Date: |
Thu, 02 Dec 1999 11:36:15 -0700 |
Forgot a semi-colon.
## usage: polyvalm (c, x)
##
## Evaluate a polynomial in the matrix sense.
##
## In octave, a polynomial is represented by it's coefficients (arranged
## in descending order). For example a vector c of length n+1
corresponds
## to the following nth order polynomial
##
## p(x) = c(1) x^n + ... + c(n) x + c(n+1).
##
## polyvalm(c,X) will evaluate the polynomial in the matrix sense, i.e.
matrix
## multiplication is used instead of element by element multiplication
as is
## used in polyval.
##
## X must be a square matrix.
##
## SEE ALSO: polyval, poly, roots, conv, deconv, residue, filter,
## polyderiv, polyinteg
## Author: Tony Richardson <address@hidden>
## Created: June 1994
## Adapted-By: jwe
## Changed-By: Ross Lippert <address@hidden,sandia.gov>
function y = polyvalm (c, x)
if (nargin != 2)
usage ("polyvalm (c, x)");
endif
if (! (is_vector (c) || isempty (c)))
error ("polyvalm: first argument must be a vector.");
endif
if (! is_square (x))
error("polyvalm: second argument must be a square matrix.");
endif
if (isempty (c))
y = [];
return;
endif
n = length(c);
I = eye(rows(x),columns(x));
y = c(1) * I;
for index = 2:n,
y = c(index)*I + x*y;
endfor
if (is_symmetric (x))
y = (y+y')/2;
endif
endfunction
- polyvalm.m, Ross A. Lippert, 1999/12/02
- Re: polyvalm.m,
Ross A. Lippert <=