larry-discuss team mailing list archive

[Keith Goodman <kwgoodman@xxxxxxxxx>]

On Fri, Feb 5, 2010 at 9:37 AM, Keith Goodman <kwgoodman@xxxxxxxxx> wrote:
> On Fri, Feb 5, 2010 at 9:19 AM,  <josef.pktd@xxxxxxxxx> wrote:
>> On Fri, Feb 5, 2010 at 12:01 PM, Keith Goodman <kwgoodman@xxxxxxxxx> wrote:
>>> On Fri, Feb 5, 2010 at 8:52 AM, Keith Goodman <kwgoodman@xxxxxxxxx> wrote:
>>>> On Fri, Feb 5, 2010 at 7:28 AM, Keith Goodman <kwgoodman@xxxxxxxxx> wrote:
>>>>> On Fri, Feb 5, 2010 at 7:24 AM,  <josef.pktd@xxxxxxxxx> wrote:
>>>>>> The current signature
>>>>>>
>>>>>> assert_larry_equal(actual, desired, msg='', dtype=True, original=None,
>>>>>>                       noreference=True, nocopy=False)
>>>>>>
>>>>>> has 3 keywords, original, noreference, nocopy for the option to check
>>>>>> whether a larry is a view or a copy.
>>>>>>
>>>>>> This makes 8 binary options, only 3 are relevant cases, the other 5
>>>>>> combinations raise errors or are redundant. This was quite confusing
>>>>>> when I used the tests, since I often forgot to use, reset a keyword,
>>>>>> e.g. nocopy=True also requires setting noreference = False
>>>>>>
>>>>>> I think a more compact signature would be
>>>>>> assert_larry_equal(actual, desired, msg='', dtype=True, original=None,
>>>>>> noref=True)
>>>>>>
>>>>>> if not original is None:
>>>>>>    if noref:
>>>>>>       check noreference
>>>>>>    else:
>>>>>>       check nocopy
>>>>>>
>>>>>> otherwise don't do any reference/copy check
>>>>>>
>>>>>> the presence of original would indicate that we want the view check,
>>>>>> `noref` would tell which one.
>>>>>
>>>>> This is how larry gets improved---with cleaning like that.
>>>>>
>>>>> I'll make the change in the trunk.
>>>>
>>>> I changed the function signature as you suggested. I also changed
>>>> noref to iscopy. The change in the kw name will mess up your unit
>>>> tests :(
>>
>> I will change them
>>
>>>>
>>>> And I change the name of assert_noreference to assert_iscopy and
>>>> assert_nocopy to assert_isview.
>>>
>>> Here's a potential problem if the label contains objects:
>>>
>>>>> import datetime
>>>>> x = larry([1, 2] , [[9, datetime.date(2009,1,1)]])
>>>>> y = larry([1, 2] , [[7, x.label[0][1]]])
>>>>> x.label[0][1] is y.label[0][1]
>>>   True
>>>>> la.util.testing.assert_iscopy(x, y)
>>>>>
>>>
>>> assert_iscopy and assert_isview only compare the entire axis at once:
>>>
>>>    for i in xrange(larry1.ndim):
>>>        if larry1.label[i] is larry2.label[i]:
>>>            msg.append('The labels along axis %d share a reference.' % i)
>>>
>>> So I should change that to loop over each label element, right?
>>
>> Yes. Because this is for the tests, we want to catch all cases, even
>> if they don't show up in common usage.
>>
>> Do we have the same problem with nested labels, e.g. tuples after
>> flatten?  Maybe then a recursive helper function is useful.
>
> Now I know why I didn't check each label element:
>
>>>> 9 is 9
> True
>
> So I need to check if the object is immutable. Do you know how to do
> that? A tuple is immutable, but not the elements inside. Seems
> complicated.

I'm only comparing, or trying to compare, label elements that are in
the same position in both larrys. I guess label element i along axis j
in larry1 should instead be compared to all label elements in larrys2
to search for references. That might actually be easier to code. We'd
need a function that collapses tuples and lists into a single list and
then do all cross comparisons. The unit test larrys are small so it
should not take long. And after comparing i with j we wouldn't need to
compare j to i.