Subject: Re: Bug on 0.4.9 ? Newsgroups: gmane.comp.python.scientific.user Date: Thursday 8th June 2006 13:13:35 UTC (over 11 years ago) DE MENTEN Sebastien wrote: > In scipy 0.4.9, you get your results if you compute cov(transpose(t)) > instead of cov(t). Thanks Sebastien, you are right. It seems semantic of covariance funcion (scipy.cov) has changed. BEAWARE this may make your programs give wrong results if updating from 0.4.8 to 0.4.9. The solution is using cov(t, rowvar=False). This ensures code will work the same way in both versions. > However, I do not know which one should be the standard. Probably using rows as vars is good default, as it is the same used in R, but i think, this should not have been changed in minor version. This change is not present in 0.4.9 tag at track[1]. :-? I don't understand what happend. Have donwloaded anything wrong? [1] http://projects.scipy.org/scipy/scipy/browser/tags/0.4.9/Lib/stats/stats.py Another doubt, in help(scipy.cov) it says: "Help on function cov in module numpy.lib.function_base: ..." Where is it really? in scipy.stats? or in numpy? By the way, the function comment says that when a matrix is passed as argument it returns covariance matrix, but if matrix is Nx1 (or 1xN) it returns a number instead of a 1x1 matrix. I think this is not homogeneous and it is not what expected. -- Saludos, Antonio Arauzo Azofra |
|||