At Sun, 8 Aug 2010 13:12:00 -0400, Andrew W. Steiner wrote: > There was recently a big discussion in the D0 collaboration > at Fermilab about a signaling NaN popping up in uninitialized variables. > To use some GSL code to demonstrate the issue, I've copied > some of cdf/cauchyinv.c from 1.14 below (edited to make it compact). > [I'm not a member of D0 myself and don't have access to their > code.] The issue is that the optimizer is free to load values in the register > if it likes, and in particular it may do so with the variable 'x'. > Unfortunately since x is uninitialized, the value of x is determined > by whatever happens to be in memory, i.e. it might contain > a signaling NaN. In that case, a floating point exception is > triggered and the code crashes.
If that happens in the example you gave it is a compiler problem for sure. -- Brian Gough _______________________________________________ Help-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-gsl
