Re: 'orth' command -- question

[Jordi Gutiérrez Hermoso]

On 17 April 2012 08:25, James Sherman Jr. <address@hidden> wrote:
> I don't know the specific algorithm behind orth, so I can't give any
> particular insight into this algorithm.

Thankfully, 'round these parts we don't take kindly to black boxes and
secret mathematics, so you can just read it yourself:

    
http://hg.savannah.gnu.org/hgweb/octave/file/82449d607d20/scripts/linear-algebra/orth.m#l33

As you can see, orth is not much more than a wrapper to svd. You can
see here how Octave calls the SVD functions in LAPACK:

    
http://hg.savannah.gnu.org/hgweb/octave/file/82449d607d20/liboctave/dbleSVD.cc#l153

Here is one of the actual functions being called in LAPACK (the
precise function depends on the types of the operands, whether real or
complex, double or single precision):

    http://www.netlib.org/lapack/double/dgesvd.f

HTH,
- Jordi G. H.