Re: [Maxima-discuss] [Maxima-commits] [git] Maxima CAS branch master updated. branch-5_40-base-83-ged20729

[Raymond T. <toy...@gm...>]

>>>>> "Andreas" == Andreas Eder <aek...@gm...> writes:

    Andreas> On Mo 26 Jun 2017 at 20:29, Raymond Toy <toy...@gm...> wrote:

    >> On Sun, Jun 25, 2017 at 2:25 AM, Andreas Eder via Maxima-commits <
    >> max...@li...> wrote:
    >> 
    >>> commit e6a7a8af637ee29f549b1dd47633fb08172e17ae
    >>> Author: Andreas Eder (are_muc) <and...@gm...>
    >>> Date:   Sun Jun 25 11:06:41 2017 +0200
    >>> 
    >>> replaced uses of the half macro with the variable 1//2.
    >>> had to adapt relative error bounds for the erf-inverse_erf
    >>> tests
    >>> sligthly.
    >>> 
    >>> 
    >> ​This makes no sense to me.  Why should the results be different?
    >> 
    >> This needs some investigation.  Is it because the defvar version
    >> wasn't
    >> simplified?​

    Andreas> No, it is simplified.
    Andreas> The defvar is: (defvar 1//2 '((rat simp) 1 2))
    Andreas> That is, as far as I can tell, simplified.
    Andreas> What I suspect is a different order of evaluation. The macro version is
    Andreas> expande into a literal at macroexpansion time, whereas the defvar
    Andreas> generates a reference to the variable at compile time. The might lead
    Andreas> to
    Andreas> different orders of evaluation. But I'm no expert in these matters.
    Andreas> The difference is very small and I always expect such things when
    Andreas> dealing with floating point.

That might be true, but in the tests, there shouldn't be any
difference.  The VALUE being used should be exactly the same in the
numeric tests as before.

It's ok to change the thresholds when it makes sense, but I just don't
see how this is one of those cases.  You didn't change the value of
anything.

What really caused the thresholds to change?  This troubles me a
lot. (Can't investigate myself right now.)

--
Ray