adjunctMatrix

% determines adjunct matrix for a square matrix
 
 B = adjunctMatrix(A)

 inv(A) = adj(A)/det(A)   holds.
   d det(A)/ dA = adj(A)'   holds.

 author:  J. Meidow, FGAN-FOM

 $Log: adj.m,v $
 Revision 1.1  2007/09/26 06:33:52  meidow
 *** empty log message ***

 adapted Wolfgang Foerstner 1/2011
 wfoerstn@uni-bonn.de

0001 %% determines adjunct matrix for a square matrix
0002 %
0003 % B = adjunctMatrix(A)
0004 %
0005 % inv(A) = adj(A)/det(A)   holds.
0006 %   d det(A)/ dA = adj(A)'   holds.
0007 %
0008 % author:  J. Meidow, FGAN-FOM
0009 %
0010 % $Log: adj.m,v $
0011 % Revision 1.1  2007/09/26 06:33:52  meidow
0012 % *** empty log message ***
0013 %
0014 % adapted Wolfgang Foerstner 1/2011
0015 % wfoerstn@uni-bonn.de
0016 
0017 function B = adjunctMatrix(A)
0018 
0019 B = zeros(size(A));
0020 for i=1:size(A,1)
0021     idx_i = setdiff( 1:size(A,1), i);
0022     for j=1:size(A,2)        
0023         idx_j = setdiff( 1:size(A,2),j);
0024         B(i,j) = (-1)^(i+j)*det(A(idx_j,idx_i));
0025     end
0026 end