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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: ANN:Ada 2005 Math Extensions 20170427
Date: Tue, 09 May 2017 13:49:01 +0100
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Date: 2017-05-09T13:49:01+01:00
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Vincent DIEMUNSCH <vincent.diemunsch@gmail.com> writes:

> So if understand well, this is an extension of the Ada Arrays in
> row-major order, right ? How is it using Lapack since Fortran has
> column-major order for it's matrices ?

By transposing input matrices before handing over to LAPACK, and
transposing the results before handing back to the caller.

> I have also seen different projects that use Lapack :
> - Ada Lapack : https://sourceforge.net/projects/ada-lapack/

This is a translation of the Fortran library to Ada, and uses native Ada
ordering (row-major).

> - AdaLAPACK  : https://sourceforge.net/projects/adalapack/

This is a binding, and its interface is explicitly in terms of
Fortran-convention objects; for example,

   type Fortran_Real_Matrix is
     array (Fortran_Integer range <>, Fortran_Integer range <>) of Real;
   pragma Convention (Fortran, Fortran_Real_Matrix);

   ...

   procedure SGEEV
     (JOBVL : Character;
      JOBVR : Character;
      N     : Fortran_Integer;
      A     : Fortran_Real_Matrix;
      LDA   : Fortran_Integer;
      WR    : out Fortran_Real_Vector;
      WI    : out Fortran_Real_Vector;
      VL    : out Fortran_Real_Matrix;
      LDVL  : Fortran_Integer;
      VR    : out Fortran_Real_Matrix;
      LDVR  : Fortran_Integer;
      WORK  : in out Fortran_Real_Vector;
      LWORK : Fortran_Integer;
      INFO  : out Fortran_Integer);

   pragma Import (Fortran, SGEEV, "sgeev_");