Hi Xavier,
I'm sorry. As I don't know a great deal about the nuts and bolts of matplotlib,
I don't think I'm well enough equipped to answer your question. Perhaps someone
else on this list can help out?
Regards,
-- Damon
--------------------------
Damon McDougall
Mathematics Institute
University of Warwick
Coventry
CV4 7AL
d.mcdoug...@warwick.ac.uk
On 23 Nov 2009, at 21:00, Xavier Gnata wrote:
> Hi,
>
> Well when you plot, imshow or whatever is matplotlib related, the axes do
> scale *automatically*.
> Why should it be different with quiver?
>
> I do reproduce your error with axis('tight')
>
>
> Xavier
>
>> Hi Xavier (cc list),
>>
>> It may be a bug, however I do not know what the default behaviour 'should'
>> be. You could do:
>>
>> lims = [-4, 4, -4, 4]
>> axis(lims)
>>
>> after calling quiver to see the whole arrow. I did notice that calling
>>
>> axis('tight')
>>
>> threw the following error
>>
>> /Users/Damon/python/lib/matplotlib/axes.py:2038: UserWarning: Attempting to
>> set identical xmin==xmax results in singular transformations; automatically
>> expanding. xmin=1.0, xmax=1.0
>> warnings.warn('Attempting to set identical xmin==xmax results in singular
>> transformations; automatically expanding. xmin=%s, xmax=%s'%(xmin, xmax))
>> /Users/Damon/python/lib/matplotlib/axes.py:2212: UserWarning: Attempting to
>> set identical ymin==ymax results in singular transformations; automatically
>> expanding. ymin=1.0, ymax=1.0
>> warnings.warn('Attempting to set identical ymin==ymax results in singular
>> transformations; automatically expanding. ymin=%s, ymax=%s'%(ymin, ymax))
>>
>> is this correct, or is it a bug? I'm using "ipython -pylab" with the MacOSX
>> backend. I was expecting axis('tight') would scale the axes so I could see
>> the whole arrow.
>>
>>
>> Regards,
>> -- Damon
>>
>> --------------------------
>> Damon McDougall
>> Mathematics Institute
>> University of Warwick
>> Coventry
>> CV4 7AL
>> d.mcdoug...@warwick.ac.uk
>>
>> On 22 Nov 2009, at 21:34, Xavier Gnata wrote:
>>
>>
>>> Hi,
>>>
>>> RTFM...indeed it works.
>>> However, the axis do not scale accordingly:
>>>
>>> quiver([1],[1],[2],[2], angles='xy', scale_units='xy', scale=1) on a TkAgg
>>> backend produce a plot with:
>>> In [11]: axis()
>>> Out[11]:
>>> (0.94000000000000006,
>>> 1.0600000000000001,
>>> 0.94000000000000006,
>>> 1.0600000000000001)
>>>
>>> The display area scales the same way as it does using
>>> quiver([1],[1],[2],[2]) (without any other args).
>>> It looks like a bug.
>>>
>>> Xavier
>>>
>>>
>>>
>>>> Hi Xavier,
>>>>
>>>> You can pass some handy keyword arguments to fix that. Use the following:
>>>>
>>>> quiver([1],[1],[1.2],[1.2], angles='xy', scale_units='xy', scale=1)
>>>>
>>>> Hope that helps :)
>>>>
>>>>
>>>> Regards,
>>>> -- Damon
>>>>
>>>> --------------------------
>>>> Damon McDougall
>>>> Mathematics Institute
>>>> University of Warwick
>>>> Coventry
>>>> CV4 7AL
>>>> d.mcdoug...@warwick.ac.uk
>>>>
>>>> On 22 Nov 2009, at 16:37, Xavier Gnata wrote:
>>>>
>>>>
>>>>
>>>>> Hi,
>>>>>
>>>>> I woud like to draw a vector field using pylab.
>>>>> quivert looks nice but it sould not scale the arrows to fit my use-case.
>>>>> quiver([1],[1],[1.2],[1.2]) does plot a nice arrow but the head of the
>>>>> arrow is not at (1.2,1.2).
>>>>> Is there a way to plot a list of arrows *without* any scaling?
>>>>>
>>>>> Xavier
>>>>>
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>>>>
>>>>
>>>
>>
>
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