Re: Any easy/build-in construct to extract submatrices from larger matrix?

["Nasser M. Abbasi" <nma@12000.org>]

On 6/25/2012 1:49 PM, stefan-lucks@see-the.signature wrote:

> 2. Specify the precondition (optional):
>
>       function Is_Diagonal (M: Matrix) return Boolean
>         with Pre => M'First(1) = M'First(2) and M'Last(1) = M'Last(2);
>
> 3. Implement the function:
>
>       function Is_Diagonal (M: Matrix) return Boolean is
>          (for all I in M'Range(1)
>             => (for all J in M'Range(2)
>                   => (if I /= J then M(I, J) = 0.0)));
>
> This is four lines -- but the last two or three lines could be squeezed
> into a single one, if all what matters is the line count, disregarding
> readability.

That is a very nice solution. Thanks. I'll have to wait for gnat
2012 to try it. (I assume the pre above is checking for square matrix,
ps. the new iterator looks nice).

--Nasser