I cannot reproduce your results, but I wonder if the following is right: >>> a = array([1,2,3,4,5]) >>> var(a[newaxis,:]) array([ 0., 0., 0., 0., 0.]) >>> a[newaxis,:].var() 2.0 >>> a[newaxis,:].var(axis=0) array([ 0., 0., 0., 0., 0.])
Are method and function supposed to have different defaults? It looks like the method defaults to variance over all axes while the function defaults to axis=0. >>> __version__ '1.0b2.dev2192' On 8/1/06, Hanno Klemm <[EMAIL PROTECTED]> wrote: > > Hello, > > numpy.var exhibits a rather dangereous behviour, as I have just > noticed. In some cases, numpy.var calculates the variance, and in some > cases the standard deviation (=square root of variance). Is this > intended? I have to admit that I use numpy 0.9.6 at the moment. Has > this been changed in more recent versions? > > Below a sample session > > > Python 2.4.3 (#1, May 8 2006, 18:35:42) > [GCC 3.2.3 20030502 (Red Hat Linux 3.2.3-52)] on linux2 > Type "help", "copyright", "credits" or "license" for more information. > >>> import numpy > >>> a = [1,2,3,4,5] > >>> numpy.var(a) > 2.5 > >>> numpy.std(a) > 1.5811388300841898 > >>> numpy.sqrt(2.5) > 1.5811388300841898 > >>> a1 = numpy.array([[1],[2],[3],[4],[5]]) > >>> a1 > array([[1], > [2], > [3], > [4], > [5]]) > >>> numpy.var(a1) > array([ 1.58113883]) > >>> numpy.std(a1) > array([ 1.58113883]) > >>> a =numpy.array([1,2,3,4,5]) > >>> numpy.std(a) > 1.5811388300841898 > >>> numpy.var(a) > 1.5811388300841898 > >>> numpy.__version__ > '0.9.6' > > > > Hanno > > -- > Hanno Klemm > [EMAIL PROTECTED] > > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys -- and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Numpy-discussion mailing list > Numpy-discussion@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/numpy-discussion > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
