You're welcome ☺️
Le 22 mai 2017 4:05 PM, "Luis Mochan" <[email protected]> a écrit :
Hello Greg!
The warning 'that routines defined here are not optimized' was the
reason I went directly for PDL::LinearAlgebra::Real, but now that I
see the code I realize I would have been quite happy to use your nice
interface; you create in your routines the same arrays I currently
create in my code, so memory/time efficiency would not have been not
diminished.
Thanks,
Luis
On Mon, May 22, 2017 at 03:44:24PM +0200, Grégory Vanuxem wrote:
> Hello,
>
> 2017-05-21 21:27 GMT+02:00 Luis Mochan <[email protected]>:
>
> >
> >
> > Got it. I guess a short warning about column vs. row major for each
> > routine would be adequate. An alternative would be to wrap the library
> > routines with perl routines that perform the transpositions. As lapack
> > expects that consecutive data along columns are adjacent, I guess the
> > transpositions should be done first and then the data copied to the
> > arrays that would actually be fed to lapack. This is what the [phys]
> > flag in the signature does, right?
> >
> > Best regards,
> > Luis
> >
>
> This is exactly what I have done in PDL::LinearAlgebra.
> I suggest you use it, transposition will be done automatically if
necessary.
> As said by Chris, Fortran use a column major ordering in contrary to C
code.
>
> The two modules PDL::LinearAlgebra::Real and PDL::LinearAlgebra::Complex
> should only be used for optimized code and the developer has to be aware
of
> these ordering differences.
>
> The description of this generic module :
>
> DESCRIPTION
>
> This module provides a convenient interface to PDL::LinearAlgebra::Real
and
> PDL::LinearAlgebra::Complex. Its primary purpose is educational. You have
> to know that routines defined here are not optimized, particularly in term
> of memory. Since Blas and Lapack use a column major ordering scheme some
> routines here need to transpose matrices before calling fortran routines
> and transpose back (see the documentation of each routine). If you need
> optimized code use directly PDL::LinearAlgebra::Real and
> PDL::LinearAlgebra::Complex.
>
>
> Hope that helps
>
> --
> Greg
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o
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