gacontraction.m

这是几何代数的matlab工具包

function C = GAcontraction(m,n)
%GAcontraction(m,n): Computes the contraction of two GA objects.
%Takes two arguments and gives the contraction of the first
%onto the second.  This function works for scalar inputs.
%See also gable.

% GABLE, Copyright (c) 1999, University of Amsterdam
% Copying, use and development for non-commercial purposes permitted.
%          All rights for commercial use reserved; for more information
%          contact Leo Dorst ([e-mail]).
%
%          This software is unsupported.
S=GAsignature;
        M= [m.m(1) S(1)*m.m(2) S(2)*m.m(3) S(3)*m.m(4) -S(1)*S(2)*m.m(5) -S(2)*S(3)*m.m(6) -S(3)*S(1)*m.m(7) -S(1)*S(2)*S(3)*m.m(8);
	      0      m.m(1)        0             0       -S(2)*m.m(3)            0            S(3)*m.m(4)    -S(2)*S(3)*m.m(6);
	      0        0         m.m(1)          0        S(1)*m.m(2)       -S(3)*m.m(4)           0         -S(1)*S(3)*m.m(7);
	      0        0           0           m.m(1)          0             S(2)*m.m(3)     -S(1)*m.m(2)    -S(1)*S(2)*m.m(5);
	      0        0           0             0           m.m(1)              0                 0           S(3)*m.m(4);
	      0        0           0             0             0               m.m(1)              0           S(1)*m.m(2);
	      0        0           0             0             0                 0               m.m(1)        S(2)*m.m(3);
	      0        0           0             0             0                 0                 0             m.m(1)];
         C = GA(M*n.m);