%
%  macm 202 -- 31 mar 03 -- djm
%
%  w12shuff8.m:  

Ncards = 52;  Nh = Ncards/2;  Nshuffles = 8;

%  make the permutation matrix for the shuffle
Pn = zeros(Ncards,Ncards);
for k=1:Nh
    Pn(2*k-1,   k) = 1;
    Pn(2*k  ,Nh+k) = 1;
end

%  make it go fast (special "sparse" matrix form)
Pn = sparse(Pn);

figure(1); clf

%  no shuffles yet
shuff = eye(Ncards);
spy(shuff);
title(['\bf after shuffles # ' num2str(0)])

%  loop over shuffle matrices
for k=1:Nshuffles
    pause(1)
    shuff = Pn*shuff;
    spy(shuff)
    title(['\bf after shuffles # ' num2str(k)])
end