function F = Frame(fname,v1,v2,v3,n1,n2,n3)%Frame(fname,v1,v2,v3,n1,n2,n3): Creates a frame for GA basis vectors %Takes a name, and three linearly independent vectors (of type GA) % and optionally the three vectors can be named, %If they are not named, then the names are the frame name followed by % 1,2, or 3 respectively.%%See also gable, FE, OFrame.% 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 (leo@wins.uva.nl).%%          This software is unsupported. if nargin < 4    disp('The frame needs a name, and three linearly independent vectors.');    F.m=eye(8);    F.b1='e1';    F.b2='e2';    F.b3='e3'; else    if nargin < 7       n1=[fname,'1'];       n2=[fname,'2'];       n3=[fname,'3'];    else    end    if isa(v1,'GA')&isa(v2,'GA')&isa(v3,'GA')       E=v1^v2^v3;       EM=E.m;       W=EM(8);       if W == 0	  disp('The frame needs three linearly independent vectors.');	  F.m=eye(8);	  F.b1='e1';	  F.b2='e2';	  F.b3='e3';       else	  r1=(1/W)*Edual(v2^v3);	  r2=(1/W)*Edual(v3^v1);	  r3=(1/W)*Edual(v1^v2);%Bivectors	  r12=r1^r2;	  r23=r2^r3;	  r31=r3^r1;	  G=[1,0,0,0,0,0,0,0; 	     r1.m'; 	     r2.m'; 	     r3.m';	     r12.m';	     r23.m';	     r31.m';	     0,0,0,0,0,0,0,1/W];	  F.m=G;	  F.b1=n1;	  F.b2=n2;	  F.b3=n3;       end    else       disp('The frame needs three linearly independent vectors.');       F.m=eye(8);       F.b1='e1';       F.b2='e2';       F.b3='e3';    end end