Re: Higher precision and generics

[ucaa2385@alpha1.csv.ica.uni-stuttgart.de (Peter Hermann)]

Mats Weber (Mats.Weber@matrix.ch) wrote:
: In article <3jsnbf$ido@nef.ens.fr>, sands@clipper.ens.fr (Duncan Sands) wrote:

: > I am writing a package of matrix routines (in Ada!) in which some
: intermediate results
: > should be calculated in higher precision than normal.  The type for
: normal precision is
: > called Real and is a generic parameter of my package:
: > generic
: >    type Real is digits <>;
: > package Matrix_Stuff is
[snip]
: generic
:    type Real is digits <>;
:    type Double_Real is digits <>;
: package Matrix_Stuff is
:    ...
: end;

I do not favor Mats' solution.
We had the same situation about 20 years ago in a major finite element code:
people believed it to be useful to have Fortran code with mixed precision.
This turned out to become far too complex!
I would recommend to use the above (first) generic package in a 
straightforward manner, i.e. once instantiated for a single precision type,
next time for a double precision type (in Fortran-speak).
That's what generic units are for.

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Peter Hermann  Tel:+49-711-685-3611 Fax:3758 ph@csv.ica.uni-stuttgart.de
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