[Python-Dev] Nondeterministic long-to-float coercion (original) (raw)

Bryan O'Sullivan bos at serpentine.com
Thu Oct 19 23:08:33 CEST 2006

Raymond Hettinger wrote:

My colleague got an odd result today that is reproducible on his build of Python (RedHat's distribution of Py2.4.2) but not any other builds I've checked (including an Ubuntu Py2.4.2 built with a later version of GCC). I hypothesized that this was a bug in the underlying GCC libraries, but the magnitude of the error is so large that that seems implausible.

These errors are due to a bit or two being flipped in either the long or double representation of the number. They could be due to a compiler bug, but other potential culprits include bad memory, a bum power supply introducing noise, or cooling problems.

Has your colleague run memtest86 or other load tests for a day on their box?

<b

More information about the Python-Dev mailing list