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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Ada.Numerics.Long_Real_Arrays
Date: Wed, 25 Jan 2017 16:17:01 +0000
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Date: 2017-01-25T16:17:01+00:00
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hnptz@yahoo.de writes:

> On Wednesday, January 25, 2017 at 1:25:18 PM UTC+1, hn...@yahoo.de wrote:
>> Hi,
>> 
>> these are my definitions:
>> 
>> with Ada.Numerics.Long_Real_Arrays; use Ada.Numerics.Long_Real_Arrays;
>> package nm is
>> 
>> Np : Positive;
>> Type R_Vector is new Real_Vector (1..Np);
>> Type R_Matrix is array (Positive range <>) of R_Vector;
>> 
>> procedure nm1 (P : in out R_Matrix);
>> 
>> end nm;

> First, I want to keep the length of P open until I fix it in
> test_nm.adb. The length of R_Vector is always Mp-1.  Second, I want to
> use the builtin Real_Vector arithmetic, that I do not have to resort
> to loops. Using Real_Matrix definitions won't allow it, as slices of
> n-dimensional arrays are not possible.

You could try a generic?

with Ada.Numerics.Long_Real_Arrays;
generic
   Rows : Positive;
package Nm_G is
   subtype R_Vector
     is Ada.Numerics.Long_Real_Arrays.Real_Vector (1 .. Rows - 1);
   type R_Matrix is array (1 .. Rows) of R_Vector;
end Nm_G;

with Ada.Text_Io; use Ada.Text_Io;
with Nm_G;
procedure Nm_Test is
   package Nm is new Nm_G (Rows => 3);
   use Nm;
   P : R_Matrix := ((42.0, 42.0), (43.0, 43.0), (44.0, 44.0));
   V : R_Vector := P (P'Last);
begin
   Put_Line ("v: " & V (V'First)'Img & ", " & V (V'Last)'Img);
end Nm_Test;