samer@4: function t=inv_triu(t)
samer@4: % inv_triu - Inverse of upper triangular matrix
samer@4: % 
samer@4: % inv_triu :: [[N,N]] -> [[N,N]].
samer@4: 
samer@4: n=size(t,1);
samer@4: for k=1:n
samer@4: 	if t(k,k)~=0
samer@4: 		t(k,k) = 1/t(k,k);
samer@4: 		t(1:k-1,k) = -t(1:k-1,k) * t(k,k);
samer@4: 
samer@4: 		j = k+1:n;
samer@4: 		temp = t(k,j);
samer@4: 		t(k,j) = 0;
samer@4: 		t(1:k,j) = t(1:k,j) + t(1:k,k)*temp;
samer@4: 	end
samer@4: end
samer@4: 
samer@4: