[pymvpa] An error occurs when I use the function "zscore" ...

冯璐 fenglu at fingerpass.net.cn
Thu Feb 9 11:58:11 UTC 2012


Okay. That's what I need. Thank you.

Best wishes!

     Lu FENG
fenglu at fingerpass.net.cn


-----Original Message-----
From: pkg-exppsy-pymvpa-bounces+fenglu=fingerpass.net.cn at lists.alioth.debian.org [mailto:pkg-exppsy-pymvpa-bounces+fenglu=fingerpass.net.cn at lists.alioth.debian.org] On Behalf Of Michael Hanke
Sent: 2012年2月9日 19:45
To: Development and support pf PyMVPA
Subject: Re: [pymvpa] An error occurs when I use the function "zscore" ...

On Thu, Feb 09, 2012 at 07:30:06PM +0800, 冯璐 wrote:
> 
> But if I use the code like this,
> 	zscore(dataset, targetdtype="float32"),
> the result seems reasonable.
> 
> The declaration of the function "zscore" is like this,
> 	zscore(dataset, mean=None, std=None, perchunk=True, baselinelabels=None, pervoxel=True, targetdtype="float32").
> It also said that,
> 	"If 'baselinelabels' provided, and 'mean' or 'std' aren't provided, it would compute the corresponding measure based only on labels in 'baselinelabels'."
> 
> I'm puzzled. When mean=std=baselinelabels=None, what happened to the dataset?

In this case the features get zscored base on the feature mean and std (computed
over all samples). mean, std are there to allow specification of
particular values derived from something else than the dataset at hands.
baselinelabels allows you to derive the mean and std from a subset of
samples within the dataset -- maybe to compute something like "deviation
from baseline" by zscoring based on that.

HTH,

Michael

-- 
Michael Hanke
http://mih.voxindeserto.de

_______________________________________________
Pkg-ExpPsy-PyMVPA mailing list
Pkg-ExpPsy-PyMVPA at lists.alioth.debian.org
http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-exppsy-pymvpa
 

__________ Information from ESET NOD32 Antivirus, version of virus signature database 6865 (20120207) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com
 
 

__________ Information from ESET NOD32 Antivirus, version of virus signature database 6865 (20120207) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com
 




More information about the Pkg-ExpPsy-PyMVPA mailing list