2008/5/7 Pierre GM <[EMAIL PROTECTED]>: > On Wednesday 07 May 2008 20:38:22 Anne Archibald wrote: > > 2008/5/7 Pierre GM <[EMAIL PROTECTED]>: > > > All, > > > Yes, there is a problem with ma.power: masking negative data should be > > > restricted to the case of an exponent between -1. and 1. only, don't you > > > think ? > > > > No, there's a problem with any fractional exponent (with even > > denominator): x**(3/2) == (x**3)**(1/2). > > Argh. Good point. > > > > The real > > problem is "how do we predict when power() is going to produce a NaN?" > An alternative would be to forget about it: let power() output NaNs, and fix > them afterwards with fix_invalid.
Tempting, but the user may have used seterr() to arrange that exceptions are raised when this happens, which is going to put a spanner in the works. (And temporarily changing seterr() is problematic in a multithreaded context...) Anne _______________________________________________ Numpy-discussion mailing list [email protected] http://projects.scipy.org/mailman/listinfo/numpy-discussion
