Re: [Matplotlib-users] MemoryError with import matplotlib

Works for me on Windows 7 64 bit with 32 bit Python. I believe you 
simply run out of memory. On a 32 bit Windows OS, Python can only use 2 
GB, which it has to share with other all processes. 
zeros((300,300,300,4),dtype=float64) requires ~820MB of contiguous 
memory, which might not be available even if you have >1 GB free RAM. 
Better use a 64 bit OS and Python.

Christoph

On 1/14/2011 11:40 AM, sprobst wrote:
>
> Hi all,
>
> I tried to plot parts of a large 3D array with each 4 float64 entries.
> Loading the array with numpy.fromfile and performing a type conversion
> afterwards ends up in a MemoryError.
>
> The following code reproduces the error:
> ***********************************
> import gc
>
> from os import path
> from numpy import zeros, empty, float32, float64, fromfile
>
> # With the imports of the next three lines a memory error occurs
> #import matplotlib
> #matplotlib.use("AGG")
> #import matplotlib.pylab as plt
>
> _filename = "mt.dat"
>
> if (path.exists(_filename)==False):
> 	print "Write file ..."
> 	_mtf = file(_filename, "wb")
> 	_mtd = zeros( (300,300,300,4),dtype=float64)
> 	_mtd.tofile(_mtf)
> 	_mtf.close()
> 	
> 	_mtd = empty((0))
> 	gc.collect();
>
> print "Try to read file ..."
>
> _mtf = file(_filename, "rb")
> # The memory error occurs with the type conversion to float 64,
> # but only if mathplotlib is imported!
> _mtd = fromfile(_mtf,float64).astype(float32)
> _mtf.close()
>
> print "Successful read:",_mtd.shape
>
> # Here some plot stuff would be :)
> ***********************************
>
> If the import of matplotlib is not included, no error occures otherwise it
> will not work. Perhaps anybody can help me (I tested it only on a Windows XP
> 32Bit).
>
>       Best regards and thank you
>                Stefan