This looks good:

...

import numpy as np x = np.random.rand(2,3) x.mean(None, out=x)

ValueError: wrong shape for output But this is strange:

...

x.std(None, out=x) 0.28264369725 x

array([[ 0.54718012, 0.94296181, 0.23668961], [ 0.35561918, 0.80860405, 0.96713833]])

...

x.var(None, out=x)

0.0798874595952

...

x

array([[ 0.54718012, 0.94296181, 0.23668961], [ 0.35561918, 0.80860405, 0.96713833]])

...

x.var(0, out=x)

array([ 0.0091739 , 0.004513 , 0.13338883])

...

x

array([[ 0.54718012, 0.94296181, 0.23668961], [ 0.35561918, 0.80860405, 0.96713833]]) I'm using numpy 1.0.4 from Debian Lenny.