From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.1 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: from second.openwall.net (second.openwall.net [193.110.157.125]) by inbox.vuxu.org (Postfix) with SMTP id 9F13F267F9 for ; Sun, 10 Mar 2024 22:19:02 +0100 (CET) Received: (qmail 11607 invoked by uid 550); 10 Mar 2024 21:14:53 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 11572 invoked from network); 10 Mar 2024 21:14:53 -0000 Date: Sun, 10 Mar 2024 17:19:06 -0400 From: Rich Felker To: musl@lists.openwall.com Message-ID: <20240310211906.GV4163@brightrain.aerifal.cx> References: <20240310200040.GF1884416@port70.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240310200040.GF1884416@port70.net> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] [PATCH] complex: fix comment in cacosh On Sun, Mar 10, 2024 at 09:00:40PM +0100, Szabolcs Nagy wrote: > The principal experssions defining acosh and acos are such that > > acosh(z) = +-i acos(z) > > where the + is only true on the Im(z)>0 half of the complex plane > (and partly on Im(z)==0 depending on number representation). > > fix the comment without expanding on the details. > --- > src/complex/cacosh.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/src/complex/cacosh.c b/src/complex/cacosh.c > index 76127f75..586328ce 100644 > --- a/src/complex/cacosh.c > +++ b/src/complex/cacosh.c > @@ -1,6 +1,6 @@ > #include "complex_impl.h" > > -/* acosh(z) = i acos(z) */ > +/* acosh(z) = +-i acos(z) */ > > double complex cacosh(double complex z) > { I'm fine with taking this patch as-is, but it naturally raises a question: should it instead be: -/* acosh(z) = i acos(z) */ +/* acosh(z) = ±i acos(z) */ IOW, should we use non-ascii characters in comments like this? My leaning would be yes, especially since it may be needed to properly attribute an algorithm or something where the only alternative is misspelling someone's name or leaving it out entirely. Really the only consideration for not doing this would be if it actively breaks compiling in some environments, but I don't think that's the case. Rich