erfc failure with large numbers

[Sergei Steshenko]

--- 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.