On Fri, Jul 18, 2014 at 9:47 PM, Charles R Harris <charlesr.harris@gmail.com> wrote:

On Fri, Jul 18, 2014 at 2:32 PM, Chris Barker <chris.barker@noaa.gov> wrote:

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On Fri, Jul 18, 2014 at 12:43 PM, Pauli Virtanen <pav@iki.fi> wrote:

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18.07.2014 22:13, Chris Barker kirjoitti: [clip]

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but an appropriate rtol would work there too. If only zero testing is needed, then atol=0 makes sense as a default. (or maybe atol=eps)

There's plenty of room below eps, but finfo(float).tiny ~ 3e-308 (or some big multiple) is also reasonable in the scale-freeness sense.

right! brain blip -- eps is the difference between 1 and then next larger representable number, yes? So a long way away from smallest representable number. So yes, zero or [something]e-308 -- making zero seem like a good idea again....

is it totally ridiculous to have the default be dependent on dtype? float32 vs float64?

Whatever the final decision is, if the defaults change we should start with a FutureWarning. How we can make that work is uncertain, because I don't know of any reliable way to detect if we are using the default value or if a value was passed in.

There are tricks like http://stackoverflow.com/questions/12265695, not that I'm suggesting to do that.