### Banded matrices, dgbbrd and indexing in clapack

Posted:

**Fri Apr 29, 2005 11:00 am**Dear Forum,

I'm trying to do an SVD of a tridiagonal matrix by using first dgbbrd

(bidiagonalization) and then dbdsdc (divide-and-conquer SVD). However,

I'm using clapack and can't get it to work. Probably I haven't done the

indexing correctly. I have tried to look at the comments and code in the

source files, but this is just confusing to me. (Looks like fortran indexing...)

Does anyone have any experience with this, and know how to properly index banded matrices?

Thanks!

Jan

I'm trying to do an SVD of a tridiagonal matrix by using first dgbbrd

(bidiagonalization) and then dbdsdc (divide-and-conquer SVD). However,

I'm using clapack and can't get it to work. Probably I haven't done the

indexing correctly. I have tried to look at the comments and code in the

source files, but this is just confusing to me. (Looks like fortran indexing...)

Does anyone have any experience with this, and know how to properly index banded matrices?

Thanks!

Jan