[ublas] [patch] matrix norms are inefficient for sparse matrices

From: Georg Baum (georg.baum_at_[hidden])
Date: 2005-07-09 15:01:07

Hello,

while playing a bit with the profiler I noticed that matrix_norm_inf 
computes the norm by iterating over each element (i, j). The same is true 
for matrix_norm_1 and matrix_norm_frobenius. This is of course 
inefficient for sparse matrices.
I wonder why that is the case? I can't believe that such an inefficient 
implementation is used without reason. Now I am wondering if I have to 
expect more surprises like that? Or did I miss something?
I attach the patch I aam currently using for interested people to play 
with. It to optimize the matrix norms and seems to work for 
matrix_norm_inf (I did not yet test the other norms).

Georg