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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Copying rows in a two dimensional array.
Date: Tue, 09 Feb 2010 09:33:53 -0500
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2010-02-09T09:33:53-05:00
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"(see below)" <yaldnif.w@blueyonder.co.uk> writes:

> On 08/02/2010 21:20, in article wccd40fpgpu.fsf@shell01.TheWorld.com,
> "Robert A Duff" <bobduff@shell01.TheWorld.com> wrote:
>
>> It's trivial if you only want slices as R-values.
>> And anyway, slices as L-values don't really work:
>
> I can't agree. I have this code:
>
> procedure FFT_to_HWT (FFTCs    : in  complex_array; ...
>                       HWT_tree : out complex_array; ...) is
> ...
>    iFFTCs : complex_array (1..f(FFTCs'length));
> begin
> ...
>    iFFTCs(1..nr_bins) := FFTCs(first_bin..last_bin);
>    iFFTCs(nr_bins+1..iFFT_size) := (others => (0.0,0.0));
>    inverse_FFT(iFFTCs(1..iFFT_size));
> ...
>    HWT_tree(next_HWTC..next_HWTC+iFFT_size-1) := iFFTCs(1..iFFT_size);
> ...
> end FFT_to_HWT;
>
> I think that using slices as L-values as well as R-values helps to make this
> a lot clearer than it otherwise would be, and probably faster as well.

"Clearer"?  Yes, I agree.  "A lot clearer"?  I don't know -- something
like:

    Copy_Slice(iFFTCs, ...);

doesn't seem so horrible.

- Bob