Re: How do I "with" Numerics without linking BLAS, LAPACK? (and more)

["J-P. Rosen" <rosen@adalog.fr>]

Le 31/08/2010 10:24, Jerry a �crit :
> This is probably going to be confusing...
> 
> I have a problem with the PLplot bindings to which I can't figure out
> a decent solution.
> 
> The Ada bindings use vectors and matrices defined like this:
> 
>     type Real_Vector is array (Integer range <>) of Long_Float;
>     type Real_Matrix is array (Integer range <>, Integer range <>) of
> Long_Float;
> 
> These can be either defined exactly like the above in the bindings
> proper or, in the case of Ada 2005, from the declarations from GNAT's
> a-nlrear.ads which are effectively exactly the same. For example,
> these subtypes work: (Subtyping makes distributing the declaration to
> the various packages easy.)
> 
>     with Ada.Numerics.Long_Real_Arrays;
>     subtype Real_Vector is Ada.Numerics.Long_Real_Arrays.Real_Vector;
>     subtype Real_Matrix is Ada.Numerics.Long_Real_Arrays.Real_Matrix;
> 
> As long as the user program uses whichever of these types is specified
> in the bindings, the program will work OK. But there are two problems.
> 
> (1) (Compiler is Ada 2005.) [...] if
> the user simply wants to use the "official" types, the second method
> is the only way to go because the first declaration style will result
> in types that are incompatible with a-nlrear.ads.
> 
Not really, since they are convertible to the types in a-nlrear.ads.
That would require a bit of extra typing when calling the functions, but
likely zero run-time overhead.

(Array conversions can be quite useful - but few people are aware of
this possibility).
-- 
---------------------------------------------------------
           J-P. Rosen (rosen@adalog.fr)
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