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From: warren@atmos.washington.edu (David Warren)
Newsgroups: comp.unix.ultrix,comp.lang.fortran
Subject: Re: How to detect NaN's
Message-ID: <WARREN.91May31174433@stormy.atmos.washington.edu>
Date: 1 Jun 91 00:44:33 GMT
References: <1991May30.204332.16506@litwin.com>
Sender: news@milton.u.washington.edu (News)
Organization: Dept. of Atmospheric Sciences, University of Washington
Lines: 40
In-Reply-To: vlr@litwin.com's message of 30 May 91 20:43:32 GMT

In article <1991May30.204332.16506@litwin.com> vlr@litwin.com (Vic Rice) writes:

   Xref: milton comp.unix.ultrix:6260 comp.lang.fortran:3304
   Path: milton!hayes.ims.alaska.edu!bionet!uwm.edu!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!dynsim1!litwin!vlr
   From: vlr@litwin.com (Vic Rice)
   Newsgroups: comp.unix.ultrix,comp.lang.fortran
   Date: 30 May 91 20:43:32 GMT
   Organization: Litwin Process Automation
   Lines: 9

   I have encountered a problem on a DECStation 5000 using the Mips Fortran
   compiler. Some operation I am performing is generating a NaN which then
   proceeds to propogate to other dependent variables. Since this is in
   a loop, I am not exactly sure where it starts.

   How can I test a variable for the presence of a NaN or Infinity ???
   -- 
   Dr. Victor L. Rice
   Litwin Process Automation


how about linking with this c function:

int *check_nan_(num)
/*make sure num != NaN*/
float *num;
{
    int true=1,false=0;
    if(isnan((double)num))return(&true);
    else return(&false);
}

then do

ISTAT = CHECK_NAN(RVAL)
--
David Warren 		INTERNET: warren@atmos.washington.edu
(206) 543-0945		UUCP:	  uw-beaver!atmos.washington.edu!warren
Dept of Atmospheric Sciences, AK-40
University of Washington