#
#
#   function [Xr,Xc,Phi,Gamma,Lambda2,pc,ac]=corresp(N)
#
#   Performs correspondence analysis on a contingency table N
#
#   Input:   N
#
#   Output:
#            Xr        (representation of rows)
#            Xc        (representation of columns)
#            Phi       Standard coordinates of rows
#            Gamma     Standard coordinates of columns
#            Lambda2   vector containing squared singular values
#            pc        vector containing percentages of Lambda2
#            ac        vector containing cumulative percentages of Lambda2
#
#
#  Needs:
#     profile.m
#     percent.m
#
function [Xr,Xc,Phi,Gamma,Lambda2,pc,ac]=corresp(N)
   [P,Q,A,B,n,p,q]=profile(N);
   [U,Lambda,V]=svd((diag(p))^(-0.5)*(N/n-p*q)*(diag(q))^(-0.5),0);
   Lambda2=(diag(Lambda.*Lambda))';
   [fp,pc,ac,np]=percent(Lambda2);
   Xr=(diag(p))^(-0.5)*U*Lambda;
   Xc=(diag(q))^(-0.5)*V*Lambda;
   Phi=(diag(p))^(-0.5)*U;
   Gamma=(diag(q))^(-0.5)*V;
endfunction