Hi,

I've seen references to scaling columns to make then have the same norm

http://icl.cs.utk.edu/lapack-forum/view ... 25890fd1a4

and that for least squares problems, A (to solve A'Ax = A'b) can't be row scaled but column scaling might be prudent if using SVD or QR with column pivoting.

http://icl.cs.utk.edu/lapack-forum/view ... 25890fd1a4

Question - is there a BLAS/LAPACK routine that will do column scaling only? I haven't been able to find one so far (row and column scaling, yes, but not column scaling only). If no, is it better to make the column norms be equal to 1 (i.e. use the column norms as the scale factors) or the max value in each column equal to 1 (use the max value in each column as scale factors)? I'm wondering if there is a rule of thumb or is it really problem dependent. Thanks.

Ken