From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <glibc-bugs-return-18181-listarch-glibc-bugs=sources.redhat.com@sourceware.org>
Received: (qmail 2737 invoked by alias); 20 Mar 2013 00:53:18 -0000
Mailing-List: contact glibc-bugs-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <glibc-bugs.sourceware.org>
List-Subscribe: <mailto:glibc-bugs-subscribe@sourceware.org>
List-Post: <mailto:glibc-bugs@sourceware.org>
List-Help: <mailto:glibc-bugs-help@sourceware.org>, <http://sourceware.org/lists.html#faqs>
Sender: glibc-bugs-owner@sourceware.org
Received: (qmail 2708 invoked by uid 48); 20 Mar 2013 00:53:10 -0000
From: "jsm28 at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug math/15287] New: casinh inaccurate for imaginary part of argument = 1 and small real part
Date: Wed, 20 Mar 2013 00:53:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: glibc
X-Bugzilla-Component: math
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jsm28 at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at sourceware dot org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-15287-131@http.sourceware.org/bugzilla/>
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
X-SW-Source: 2013-03/txt/msg00080.txt.bz2

http://sourceware.org/bugzilla/show_bug.cgi?id=15287

             Bug #: 15287
           Summary: casinh inaccurate for imaginary part of argument = 1
                    and small real part
           Product: glibc
           Version: 2.17
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
        AssignedTo: unassigned@sourceware.org
        ReportedBy: jsm28@gcc.gnu.org
    Classification: Unclassified


The implementation of casinh is substantially inaccurate for arguments with
imaginary part 1 (or -1) and small real part.  For example, on x86_64, casinh
(0x1p-30 + 1.0i) should return 0x1.64564057723e9p-15 + 0x1.921cec97c2264p+0i
but returns 0x1.0000000155515p-15 + 0x1.921db54442d43p+0i, with both parts
substantially inaccurate.  For subnormal arguments (e.g. 0x1.fp-1025), the
inaccurate results underflow where the correct results would not, with
associated underflow exceptions.  Much the same issues affect casin and cacos
for appropriate inputs to those functions.

Patch: http://sourceware.org/ml/libc-alpha/2013-03/msg00465.html

-- 
Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.