On Mon, Sep 29, 2008 at 4:40 PM, Charles R Harris <[EMAIL PROTECTED] > wrote:
> > > On Mon, Sep 29, 2008 at 4:28 PM, Robert Kern <[EMAIL PROTECTED]>wrote: > >> On Mon, Sep 29, 2008 at 17:13, Charles R Harris >> <[EMAIL PROTECTED]> wrote: >> > >> > On Mon, Sep 29, 2008 at 3:52 PM, Charles R Harris >> > <[EMAIL PROTECTED]> wrote: >> >> >> >> Hi All, >> >> >> >> I've been cleaning up the ufunc loops and the sign function currently >> >> doesn't have a defined behavior for nans. This makes the results depend >> on >> >> the order/type of comparisons in the code, which looks fragile to me. >> So >> >> what should it return? I vote for nan but am open for suggestions. >> > >> > And while we're at it, lets decide how to treat max/min when nans are >> > involved. Or should we just say the behavior is undefined. >> >> When feasible, I would like float(s)->float functions to return NaN >> when given a NaN as an argument. At least as the main versions of the >> function. Specific NaN-ignoring functions can also be introduced, but >> as separate functions. I don't know what exactly to do about >> float->int functions (e.g. argmin). I also don't know how these should >> interact with the current seterr() state. >> > > So the proposition is, sign, max, min return nan when any of the arguments > is nan. > > +1 > I also propose that all logical operators involving nan return false, i.e., ==, !=, <, <=, >, >=, and, or, xor, not.
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