From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <fortran-return-51159-listarch-fortran=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 97928 invoked by alias); 4 Oct 2018 21:17:13 -0000
Mailing-List: contact fortran-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <fortran.gcc.gnu.org>
List-Subscribe: <mailto:fortran-subscribe@gcc.gnu.org>
List-Post: <mailto:fortran@gcc.gnu.org>
List-Help: <mailto:fortran-help@gcc.gnu.org>, <http://sourceware.org/lists.html#faqs>
Sender: fortran-owner@gcc.gnu.org
Received: (qmail 97919 invoked by uid 89); 4 Oct 2018 21:17:12 -0000
Authentication-Results: sourceware.org; auth=none
X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=clarification, H*i:sk:4db6fca, H*f:sk:4db6fca, H*c:alternative
X-HELO: mail-ed1-f51.google.com
Received: from mail-ed1-f51.google.com (HELO mail-ed1-f51.google.com) (209.85.208.51) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 04 Oct 2018 21:17:10 +0000
Received: by mail-ed1-f51.google.com with SMTP id g26-v6so9880406edp.0        for <fortran@gcc.gnu.org>; Thu, 04 Oct 2018 14:17:10 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;        d=gmail.com; s=20161025;        h=mime-version:references:in-reply-to:from:date:message-id:subject:to         :cc;        bh=CelviUWvCZQwFKi/SoUslixN4INCVnZc62xGf08a4pI=;        b=TEW9ZCPMap1evWhEuk7qrqbdVgS361NNJ8DUGHtLTnxO5OAt30sICJtTzg98j1sMyu         lVNkGMz7yhnncMAXPgEzp0lq2yth3n2edmRe9GPajbijeU3iQemrpicxVx49GLwKgnbB         JCIlBhzbrsJvPTkBomstBBqGNyg+yr2dpmF5ucE7ip2lEYBR9Qqsb0i1KwlRZiIcW5Gs         mZaGuL9FQjUpqjW27L6dJZ2LgI+iHKRa7yxcrhFNehvCXjC/H9HfwxuOBtJKYmxD0xH/         XIjjSGxfMFtsuwwgdeNQrGG1xszTPmXXAWsbRM78Lj93nSGGbhSG49ORbiPhD4z1MTeo         Cdxg==
MIME-Version: 1.0
References: <CAC5oXR28H5tLKDV_hxLo0zn-BnEMjt7kVF6ZSA6bajmcN6aVnA@mail.gmail.com> <4db6fcae-c909-faf1-6074-e8e2f516c163@netcologne.de>
In-Reply-To: <4db6fcae-c909-faf1-6074-e8e2f516c163@netcologne.de>
From: Luca Donatini <lucadonatini.k@gmail.com>
Date: Thu, 04 Oct 2018 21:17:00 -0000
Message-ID: <CAC5oXR1XFfHWHtZfuO9=8UFuQ4r60cWnnrP3aAZ59vc3w7-iwA@mail.gmail.com>
Subject: Re: Unexpected NaN value
To: Thomas Koenig <tkoenig@netcologne.de>
Cc: fortran@gcc.gnu.org
Content-Type: text/plain; charset="UTF-8"
X-SW-Source: 2018-10/txt/msg00021.txt.bz2

Dear Thomas,

Many thanks for the clarification!


Best regards,


Luca

Il gio 4 ott 2018, 22:30 Thomas Koenig <tkoenig@netcologne.de> ha scritto:

> Hi Luca,
>
> > program test
> >      implicit none
> >
> >      real :: a = -1.57079637
> >      real :: b = 2.1
> >
> >      write(*,*) cos(a)
> >      write(*,*) cos(a) **(2*b)
> >
> > end program
>
> cos(a) happens to be negative, so cos(a)**(2*b) is undefined,
> because 2*b is real.  And yes, this is expected.
>
> Regards
>
>         Thomas
>