erfc failure with large numbers

[Gabriele Pannocchia]

It works fine also for octave-3.0.1 from Debian testing.

octave:2> ver
----------------------------------------------------------------------
GNU Octave Version 3.0.1
GNU Octave License: GNU General Public License
Operating System: Linux 2.6.24-1-686 #1 SMP Thu May 8 02:16:39 UTC 2008
i686
----------------------------------------------------------------------
octave:3> erfc(1000)
ans = 0


	Gabriele
> --- On Thu, 10/30/08, Shea, Philip <pshea at dtri.net> wrote:
> 
> > From: Shea, Philip <pshea at dtri.net>
> > Subject: erfc failure with large numbers
> > To: bug at octave.org
> > Date: Thursday, October 30, 2008, 5:29 AM
> > I'm a little surprised that the library routine
> > can't handle large
> > numbers.  There are good approximations to the erfc for
> > large numbers
> > (see Proakis, John G., Digital Communications, pg. 40, eq.
> > (2-1-96)).  I
> > have attached the output of the octave bug_report function.
> >  
> > octave-3.0.1.exe:4> erfc(1000)
> >  ***MESSAGE FROM ROUTINE DERFC IN LIBRARY SLATEC.
> >  ***POTENTIALLY RECOVERABLE ERROR, PROG ABORTED, TRACEBACK
> > REQUESTED
> >  *  X SO BIG ERFC UNDERFLOWS
> >  *  ERROR NUMBER = 1
> >  *
> >  ***END OF MESSAGE
> >  
> >  ***JOB ABORT DUE TO UNRECOVERED ERROR.
> > 0          ERROR MESSAGE SUMMARY
> >  LIBRARY    SUBROUTINE MESSAGE START             NERR    
> > LEVEL
> > COUNT
> >  SLATEC     DERFC      X SO BIG ERFC UNDERF         1      
> >   1
> > 1
> >  
> >  
> > Philip A. Shea
> > DTRI
> > 1835 Alexander Bell Dr., Suite 400
> > Reston, VA 20191
> > 703-707-8555 x6270 (Office)
> > 877-383-8802 (Pager)
> >  
> 
> I can't reproduce this problem on my self-built Linux 3.0.3 'octave':
> 
> "
> octave:2> erfc(1000)
> ans = 0
> ".
> 
> Regards,
>   Sergei.
> 
> 
>       
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