%FRACITER is a subroutine of the program "fractory.m".  It generates
%the data for fractal images using a randomized algorithm.  It is
%called by the subroutine "fracdrw.m".

%Initialize variables and generate IFS sequence D2.

[KK,M]=size(A);
KK=KK/2;
S=zeros(KK+1,1);
for nn=1:KK
  S(nn+1)=abs(det(A((2*nn-1):(2*nn),:)));
end
S=max(S,sum(S)/100);
S(1)=0;
S=S/sum(S);
for nn=2:KK+1
  S(nn)=S(nn)+S(nn-1);
end
D1=rand(1,Iter);
D2=zeros(1,Iter);
for nn=1:KK
  D2=D2+nn*(D1>=S(nn) & D1<S(nn+1));
end
%clear D1
X=zeros(1,Iter+1);
Y=zeros(1,Iter+1);

%Execute IFS and store plot points in the two (Iter+1)-length
%vectors X and Y, where the nth entry of D2 is the portion of
%A and B to be applied on that iteration.

X(1)=x0;
Y(1)=y0;
for nn=1:Iter
  X(nn+1)=A((2*D2(nn)-1),:)*[X(nn) Y(nn)]' + B(2*D2(nn)-1);
  Y(nn+1)=A((2*D2(nn)),:)*[X(nn) Y(nn)]' + B(2*D2(nn));
end

if intrp
  pause(.001);
end

return