Re: [Visualpython-users] Possible memory leak

[Bruce S. <bas...@nc...>]

Thanks much for reminding me of this issue. It definitely needs a fix.

Bruce Sherwood

On Fri, Oct 29, 2010 at 8:38 AM, Beracah Yankama <be...@mi...> wrote:
> hah!  now i'm not the only one who noticed this!  i was graphing a lot
> of data too with lots of curves (a graph cluster growing to thousands of
> nodes and edges, which are dynamically positioned), but after like 200
> edges and being repositioned, an out of memory error gets thrown.  I had
> tracked it down to vpython.
>
> I had written (in case it is helpful to you):
> """
> I made a test script, that only
> creates objects in the window, then deletes them over and over, and I
> found the long-term memory use/growth to be related linearly to the .pos
> attribute.  For instance, a curve with 20 points leads to unreleased
> memory that grows 10x as fast as curves with only 2 points.  Similarly,
> if I assign the .pos attribute as a numpy ndarray directly, the leak
> grows twice as fast as if assign the individual xyz values.
> """
>
> B
>
> On 10/29/2010 9:16 AM, Jason Morgan wrote:
>> Hi,
>>
>> I am using visual python to graph a lot of data in real time (I tried with
>> matplotlib but it's just too slow).
>>
>> Anyway, it works incredibly well (thanks for a great little library by the
>> way - it's not exactly publicised just how fast and easy to use it is!!).
>>
>> I have live data on 15 separate windows, all being updated at 125 times per
>> second!!
>>
>> However, there is a problem.  After about ten minutes I get MemoryError from
>> numpy.
>>
>> The code works by using one curve per display entity.  Each curve has 300
>> x/y points.  The y points in every graph are updated each frame, the x
>> points are unchanged (0..299).
>>
>> The error comes from the line of code that shifts the data along as it adds
>> new data (I've tried various methods, including manual iteration, list
>> splices and numpy.roll) but all have the same memory effect.  I first tried
>> the old 3.x VPython and got the same results from Numeric under Python 2.5.
>> I upgraded to Python 2.7 with latest numpy and the latest VPython and got
>> the same result.
>>
>> <code>
>> for c in curves:
>>    n=curves.index(c)
>>    b=np.roll(c.y,-1)
>>    b[-1]=new_value[n]
>>    c.y=b
>> </code>
>>
>> The MemoryError is always at one of the last three lines or within numpy's
>> libraries.
>> I've tried c.get_y() and c.set_y() with the same results.
>>
>> I've checked all my other buffers in the rest of the code and non are
>> getting larger, nor is c.y or the temporary variable, b in the example
>> above.
>>
>> My conculusion is that this can only be something to do with the internal
>> workings of either numpy (and Numeric) or VPython.
>>
>> I tried the following in IDLE:
>>
>> <code>
>> import numpy as np
>> count=0
>> a=np.arange(10)
>> while True:
>>       count=count+1
>>       b=np.roll(a,-1)
>>       b[-1]=count
>>       a=b
>> </code>
>>
>> And let this run for several minutes (42+ million cycles) without a crash.
>>
>> So, what am I doing wrong (or is there a memory bug in VPython)?
>>
>> Cheers,
>> Jason.
>>
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> ------------------------------------------------------------------------------
> Nokia and AT&T present the 2010 Calling All Innovators-North America contest
> Create new apps & games for the Nokia N8 for consumers in  U.S. and Canada
> $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing
> Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store
> http://p.sf.net/sfu/nokia-dev2dev
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