[Numpy-discussion] bug in numpy.mean() ?

K.-Michael Aye kmichael.aye@gmail....
Tue Jan 24 12:33:30 CST 2012


I know I know, that's pretty outrageous to even suggest, but please 
bear with me, I am stumped as you may be:

2-D data file here:
http://dl.dropbox.com/u/139035/data.npy

Then:
In [3]: data.mean()
Out[3]: 3067.0243839999998

In [4]: data.max()
Out[4]: 3052.4343

In [5]: data.shape
Out[5]: (1000, 1000)

In [6]: data.min()
Out[6]: 3040.498

In [7]: data.dtype
Out[7]: dtype('float32')


A mean value calculated per loop over the data gives me 3045.747251076416
I first thought I still misunderstand how data.mean() works, per axis 
and so on, but did the same with a flattenend version with the same 
results.

Am I really soo tired that I can't see what I am doing wrong here?
For completion, the data was read by a osgeo.gdal dataset method called 
ReadAsArray()
My numpy.__version__ gives me 1.6.1 and my whole setup is based on 
Enthought's EPD.

Best regards,
Michael





More information about the NumPy-Discussion mailing list