erfc failure with large numbers

[Shea, Philip]

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)
 
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