Charles R Harris wrote:
So the proposition is, sign, max, min return nan when any of the arguments is nan.
Note that internally, signbit (the C function) returns an integer.
Complex numbers are more complicated because we first compare the real parts, then the imaginary. Arguably 1 > 0 + nan*1j.
Really ? Without thinking about the consequences, returning a NaN complex would be what I expect, should we go the route comparison with NaN returns a NaN.
I propose that the sign of a complex number containing nans should be nan, but I can't decide what should happen with max/min
Did you take a look at: http://projects.scipy.org/scipy/numpy/wiki/ProperNanHandling Anne and me did this, with several approaches. We did not consider interactions with the FPU error state, though, which is something which needs to be added. cheers, David