This is an Ada 2012 package that provides an interface to dense linear algebra packages. Initially the focus is on BLAS, which has been covered except for routines working on banded matrices.
Other Ada interfaces to BLAS exist, but they tend to have limitations.
Any Ada compiler that supports Interfaces.Fortran can compile an
interface that calls the routines in BLAS, passing in Ada arrays with
Convention => Fortran set or, with a little more work, mutating the
operand order and the various TRANS parameters to allow Ada arrays
with the default Convention to be used. Such an interface can do
basic linear algebra operations, but it cannot operate on sub-slices or
sub-blocks of vectors or matrices without making temporary copies.
The aim of this project is to develop a set of vector and matrix types
in a tagged type hierarchy that encompasses both types that wrap
'concrete' in-memory arrays and types that provide a 'view' onto a
slice or sub-block of one of the 'concrete' types. If A is an object
of type Concrete_Real_Matrix, for example, then A.Row(2) will
return a Real_Matrix_Vector object which can be used by any routine
which requires a vector and will operate in-place on the second row of
the matrix A. This requires some assumptions about ABI compatibility
between Ada and Fortran on the platform in question, but in practice few
problems are expected.
The Ada subprograms in LALG.Real_BLAS have the same names as in BLAS,
but without the precision specifier s or d (which are unnecessary as
LALG will have been instantiated for one precision or the other).
Parameters relating to the size or stride of the inputs are not
required, as the vector and matrix types will provide the correct
values each time.
A set of unit tests has been provided. These do not test the BLAS library for correctness or accuracy. Instead they run limited checks against each routine in the Ada interface to make sure that the interfacing with the Fortran code is functional.
Two .gpr project files have been provided for those using
GNAT/GPRBuild. There are two parameters - a mode parameters that can
be set to debug or optimize and a blas parameter that can be set
to system, netlib or openblas to select the BLAS library that you
wish to link to. It may be necessary to change the 'Linker' settings in
lalg_tests.gpr if your desired BLAS library is not in the expected
place.
The package is provided under the ISC license:
Copyright (c) 2015 - 2022, James Humphry
Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
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