From: Robert Kern <robert.kern@gm...>  20060425 17:19:48

keith.briggs@... wrote: > After "from pylab import *", log(0.0) gives > > Warning: Encountered divide by zero(s) in log > > Where is this behaviour documented? What does it mean? Why should log(0.0) divide by zero? What does the plural "zeros" refer to? Why break the IEEE standard that log(0.0) should silently return Inf? http://www.opengroup.org/onlinepubs/000095399/functions/log.html Look at the section "ERRORS", specifically "Pole Error". By and large the implementation of log() comes from the underlying libm. The plural is because log() is a ufunc and can take arrays, possibly with multiple zeros.  Robert Kern robert.kern@... "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth."  Umberto Eco 