--- a/comp/comp_dwilt.m
+++ b/comp/comp_dwilt.m
@@ -2,13 +2,66 @@
 %COMP_DWILT  Compute Discrete Wilson transform.
 %   
 
-L=size(f,1);
-Lwindow=size(g,1);
+L = size(f,1);
+a=M;
+N=L/a;
+W=size(f,2);
 
-if Lwindow<L
-  coef=comp_dwilt_fb(f,g,M,L);
+
+coef=zeros(2*M,N/2,W,assert_classname(f,g));
+
+coef2=comp_sepdgt(f,g,a,2*M);
+
+if (isreal(f) && isreal(g))
+
+    % If the input coefficients are real, the calculations can be
+  % be simplified. The complex case code also works for the real case.
+
+  % Unmodulated case.
+  coef(1,:,:)=coef2(1,1:2:N,:);
+
+  % cosine, first column.
+  coef(3:2:M,:,:)=sqrt(2)*real(coef2(3:2:M,1:2:N,:));
+  
+  % sine, second column
+  coef(M+3:2:2*M,:,:)=-sqrt(2)*imag(coef2(3:2:M,2:2:N,:));
+  
+  % sine, first column.
+  coef(2:2:M,:,:)=-sqrt(2)*imag(coef2(2:2:M,1:2:N,:));
+  
+  % cosine, second column
+  coef(M+2:2:2*M,:,:)=sqrt(2)*real(coef2(2:2:M,2:2:N,:));
+
+  % Nyquest case
+  if mod(M,2)==0
+    coef(M+1,:,:) = coef2(M+1,1:2:N,:);
+  else
+    coef(M+1,:,:) = coef2(M+1,2:2:N,:);
+  end;
+
+
 else
-  coef=comp_dwilt_long(f,g,M,L);
+  % Complex valued case
+  
+
+  % Unmodulated case.
+  coef(1,:,:)=coef2(1,1:2:N,:);
+
+  % odd value of m
+  coef(2:2:M,:,:)=1/sqrt(2)*i*(coef2(2:2:M,1:2:N,:)-coef2(2*M:-2:M+2,1:2:N,:));
+  coef(M+2:2:2*M,:,:)=1/sqrt(2)*(coef2(2:2:M,2:2:N,:)+coef2(2*M:-2:M+2,2:2:N,:));
+
+  % even value of m
+  coef(3:2:M,:,:)=1/sqrt(2)*(coef2(3:2:M,1:2:N,:)+coef2(2*M-1:-2:M+2,1:2:N,:));
+  coef(M+3:2:2*M,:,:)=1/sqrt(2)*i*(coef2(3:2:M,2:2:N,:)-coef2(2*M-1:-2:M+2,2:2:N,:));
+
+  % Nyquest case
+  if mod(M,2)==0
+    coef(M+1,:,:) = coef2(M+1,1:2:N,:);
+  else
+    coef(M+1,:,:) = coef2(M+1,2:2:N,:);
+  end;
+
 end;