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  • Committer: Bazaar Package Importer
  • Author(s): Torsten Werner
  • Date: 2002-03-21 16:57:43 UTC
  • Revision ID: james.westby@ubuntu.com-20020321165743-e9mv12c1tb1plztg
Tags: upstream-2.6
Import upstream version 2.6

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macros/calpol/sylm.sci
 
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function [s]=sylm(a,b)
 
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//[s]=sylm(a,b) gives the Sylvester matrix associated to polynomials
 
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//a and b, i.e. the matrix s such that:
 
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//  coeff( a*x + b*y )' = s * [coeff(x)';coeff(y)']
 
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//dimension of s is equal to degree(a)+degree(b)
 
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//If a and b are coprime polynomials
 
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//(rank(sylm(a,b))=degree(a)+degree(b)) the instructions
 
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//  u = sylm(a,b) \ eye(na+nb,1)
 
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//  x = poly(u(1:nb),'z','coeff')
 
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//  y = poly(u(nb+1:na+nb),'z','coeff')
 
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//compute Bezout factors x et y of minimal degree de degre minimal
 
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//such that a*x+b*y=1
 
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//!
 
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// Copyright INRIA
 
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na=degree(a);a=coeff(a)';
 
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nb=degree(b);b=coeff(b)';
 
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s(na+nb,na+nb)=0;
 
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for i=1:nb,s(i:na+i,i)=a,end
 
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for i=1:na,s(i:nb+i,nb+i)=b,end
 
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