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function T=transop(flt) 
%T=transop(flt)  
% 
%  This function computes the matrix of the transition operator corresponding  
%  to a given multiscaling function. 
%  If c is the largest eigenvalue of T which is either non-dyadic or multiple  
%  dyadic, then Sobolev regularity of the multiscaling function is higher  
%  than -log(c)/log(4).       
%  For theory and better estimates of Sobolev regularity see [J]. 
%  
%  Input: 
%    flt         string of characters, name of the filter; 
%                for possible names and short descriptions see coef.m 
% 
%  Output:  
%    T           r^2*(2*l-1) by r^2*(2*l-1) real array, matrix of the  
%                transition operator; 
%                r is the number of scaling functions, 
%                l is the number of scaling coefficients   
% 
%  Example of Usage: 
%    T=transop('ghm') 
 
% Author: Vasily Strela 
% COPYRIGHT 1997,98 by Vasily Strela 
 
[L,H]=coef(flt); 
r=length(L(:,1)); 
n=length(L(1,:))/r; 
L2=zeros(r*r,(2*n-1)*r*r); 
 
for i=1:n, 
   LL=kron(L(:,(i-1)*r+1:i*r),L(:,(i-1)*r+1:i*r)); 
   L2(:,(n-1)*r*r+1:n*r*r)=L2(:,(n-1)*r*r+1:n*r*r)+LL; 
end 
for i=1:n-1, 
  for j=1:i, 
   LL=kron(L(:,(n-i+j-1)*r+1:(n-i+j)*r),L(:,(j-1)*r+1:j*r)); 
   L2(:,(i-1)*r*r+1:i*r*r)=L2(:,(i-1)*r*r+1:i*r*r)+LL; 
   LL=kron(L(:,(j-1)*r+1:j*r),L(:,(n-i+j-1)*r+1:(n-i+j)*r)); 
   L2(:,(2*n-i-1)*r*r+1:(2*n-i)*r*r)=L2(:,(2*n-i-1)*r*r+1:(2*n-i)*r*r)+LL; 
  end, 
end 
 
r1=length(L2(:,1)); 
n1=length(L2(1,:))/r1; 
 
T1=zeros(n1*r1,n1*r1);  
for i=1:n1,  
  for j=1:n1, 
    if (0<2*i-j)&(2*i-j<=n1)  
      T1((i-1)*r1+1:i*r1,(j-1)*r1+1:j*r1)=L2(1:r1,(2*i-j-1)*r1+1:(2*i-j)*r1); 
    end 
  end, 
end 
 
T=T1(r*r+1:(2*n-2)*r*r,r*r+1:(2*n-2)*r*r);