Re: Slice from a matrix?

["David C. Hoos" <david.c.hoos.sr@ada95.com>]

"Harald Schmidt" <harald.schmidt@anobject.net> wrote in message
news:BAF3B30D.3023%harald.schmidt@anobject.net...
> Hi,
>
> I got a generic matrix / vector package like this:
>
> Generic
>     rows : positive;
>     cols : positive;
>     item_type is digits <>;
> Package matrix is
>     type vector_type is array (positive range <>) of item_type;
>     type matrix_type is array (positive range <>,
>                                positive range <>) of item_type;
>     subtype col_vector is vector_type(1..cols);
>     subtype row_vector is vector_type(1..rows);
>     subtype matrix is matrix_type(1..rows, 1..cols);
> ...
> End matrix;
>
> Then I have three Put procedures, one for matrix, one for row_vector, and
> one for col_vector.
>
> My question is how to get a slice from a matrix which I can convert to a
> col_vector which does the printing?
>
> Things like...
>
>     PUT (col_vector(M (1, 1..3)));
>
> doesn't work.
>
> I don't want to copy code for the printing routines.
Since slices in ada can only be taken from one-dimensional arrays, you
would need to declare your matrix as an array of vectors.
Individual elements are then accessed by matrix (m}{n}.

Incidentally, shouldn't a vector which is indexed by row be a column vector,
and a vector which is indexed by column be a row vector?
>
> Thanks for any help,
>
> Harald
>
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