[SciPy-Dev] Doc error in scipy.optimize.fmin and missing info in ref guide

josef.pktd@gmai... josef.pktd@gmai...
Fri Mar 19 14:37:05 CDT 2010


On Fri, Mar 19, 2010 at 3:16 PM, David Goldsmith
<d.l.goldsmith@gmail.com> wrote:
> On Mon, Mar 15, 2010 at 4:05 PM, Rob Clewley <rob.clewley@gmail.com> wrote:
>> Hi,
>>
>> In both my old version and the one in the svn trunk there is an
>> inconsistency in the docstring of scipy.optimize.fmin.
>>
>>    Other Parameters
>>    ----------------
>>    xtol : float
>>        Relative error in xopt acceptable for convergence.
>>    ftol : number
>>        Relative error in func(xopt) acceptable for convergence.
>>
>> As you see from the following code snippet from the body of the
>> function, the convergence test is in terms of absolute error for both
>> x and f, as the sim array contains x values and fsim the function
>> values.
>>
>>    if (max(numpy.ravel(abs(sim[1:]-sim[0]))) <= xtol \
>>                and max(abs(fsim[0]-fsim[1:])) <= ftol):
>>        break
>
> OK, folks, so what's the _desired_ behavior: absolute or relative
> error (i.e., where's the bug: in the code or in the doc)?

I think the docs should reflect the actual behavior of the function.
Whether the criteria will be changed and made consistent across
functions is a different question. But it's not a bug, so the docs
should adjust.

my opinion

Josef

>
> DG
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