From octave-maintainers-request at bevo dot che dot wisc dot edu Tue Nov 19 13:07:14 2002 Subject: 1^NaN and 1^Inf From: "John W. Eaton" To: octave-maintainers mailing list Date: Tue, 19 Nov 2002 13:06:41 -0600 In the last day or so, there has been a thread on the Matlab newsgroup about the values that Matlab returns for 1^NaN and 1^Inf. In both cases, Matlab returns NaN, but Octave returns whatever the C library function pow (double x, double y) returns. The GNU C library returns 1 for both cases. On other systems, we may get other results. An argument for the NaN results can be found in the paper "What Every Computer Scientist Should Know About Floating-Point Arithmetic" by David Goldberg, on page 218 at the end of the section "Ambiguity". PDF copies of this paper are available on the web, for example, I found one at http://www.nondot.org/sabre/os/files/Processors/WECSSKAFloatingPoint.pdf but a quick search will turn up many more copies. I submitted a bug report, but the maintainer of glibc, Ulrich Drepper, says that the current behavior is what the ISO C standard requires. What do people think Octave should do for these expressions? Thanks, jwe