From: Mark H Weaver <mhw@netris.org>
To: "Göran Weinholt" <goran@weinholt.se>
Cc: 14905-done@debbugs.gnu.org
Subject: bug#14905: rationalize not returning the simplest rational
Date: Sun, 21 Jul 2013 06:56:03 -0400 [thread overview]
Message-ID: <87ob9w9o70.fsf@tines.lan> (raw)
In-Reply-To: <87ehaun6ge.fsf@industria.weinholt.se> ("Göran Weinholt"'s message of "Fri, 19 Jul 2013 13:18:41 +0200")
Göran Weinholt <goran@weinholt.se> writes:
> the procedure (rationalize x1 x2) from (rnrs) takes a number x1 and
> returns the simplest rational that doesn't differ from x1 by more than
> x2. The implementation in guile has this behavior:
>
> scheme@(guile-user)> (rationalize #e-0.67 1/4)
> $1 = -2/3
>
> The problem here is that -1/2 is simpler than -2/3 (since 1<2 and 2<3)
> and it also doesn't differ from #e-0.67 by more than 1/4 (even though
> the difference is larger than for -2/3, it is still less than 1/4). So
> the result from the expression above should be -1/2.
Fixed in 620c13e8fc02060e0af8fa38398ee4de745d41e9.
Thanks!
Mark
prev parent reply other threads:[~2013-07-21 10:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-19 11:18 bug#14905: rationalize not returning the simplest rational Göran Weinholt
2013-07-21 10:56 ` Mark H Weaver [this message]
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