GNU bug report logs - #47237
[PATCH] gnu: metis: Use 64-bit floating pointer numbers on 64-bit architectures.

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Message #17 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Ludovic Courtès <ludo <at> gnu.org>
To: Paul Garlick <pgarlick <at> tourbillion-technology.com>
Cc: Emmanuel Agullo <emmanuel.agullo <at> inria.fr>,
 Eric Bavier <bavier <at> member.fsf.org>, guix-patches <at> gnu.org
Subject: Re: [PATCH] gnu: metis: Use 64-bit floating pointer numbers on
 64-bit architectures.
Date: Fri, 19 Mar 2021 10:37:31 +0100

Hi Paul and all,

Paul Garlick <pgarlick <at> tourbillion-technology.com> skribis:

> I think it is a good idea to allow for different variants, even on 64-
> bit architectures.
>
> In one direction there is a performance advantage using 32-bit floats. 
> In the other direction accuracy improves using the 64-bit data type.

True.  That concurs with what Emmanuel explains.

> There is a similar situation with the scotch library.  The scotch32
> package variant is preferable, even on 64-bit systems, except for the
> case of very large models.

Though ‘scotch32’ is about 32-bit integers, not floating point numbers.
So I guess it’s not the same kind of tradeoff?

Anyway, it sounds like the best course of action is to withdraw this
patch and instead come up with multiple variants or package parameters.

Thanks for your feedback!

Ludo’.

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