[pymvpa] Fw: Hyperalignment

[Yaroslav Halchenko]

On November 30, 2016 7:06:53 PM EST, Salim Al-wasity <salim_alwasity at yahoo.com> wrote:
>1. My datasets have similar number of features and every time I ran
>(hyper=Hyperalignment  ( )), the reference is the first dataset ds_h
>(0).
>2. I also did (hyper= Hyperalignment  (ref_ds=0)) for the second
>scenario and still getting different result tha scenario 1.
>Sincerely Salim 
>
>Sent from Yahoo Mail on Android 
> 
>On Wed, 30 Nov, 2016 at 11:14 pm, Yaroslav
>Halchenko<yoh at onerussian.com> wrote:   On November 30, 2016 5:54:36 PM
>EST, Salim Al-wasity <salim_alwasity at yahoo.com> wrote:
>Dears
>
>
>I am running a Hyperalignment analysis to investigate theeffect of the
>reference subject on the common model and between subject
>classification. I ran two scenarios to double check my results, and in
>both cases I got different classification accuracies.If I am not wrong,
>the below scenarios must giving me identical results.I had 10 subjects
>whose Hyperalignment data are stored in (ds_h) and task data in
>(ds_task) which I am classifying
>Scenario-1-:
>hyper=Hyperalignment(ref_ds=2)hypermaps=hyper(ds_h)ds_hyper = [
>hypmaps[i].forward(d_all) for i, d_all in
>enumerate(ds_task)]..........Then continue with classification
>
>Scenario-2-:new_ds_h=[ds_h[2], ds_h[0], ds_h[1], ds_h[3], ds_h[4],
>ds_h[5], ds_h[6], ds_h[7], ds_h[8],
>ds_h[9]]hyper=Hyperalignment()hyper.train(new_ds_h)hypermaps=hyper(ds_h)ds_hyper
>= [ hypmaps[i].forward(d_all) for i, d_all in
>enumerate(ds_task)]..........Then continue with classification
>
>SincerelySalim
>
>   
>
>
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>
>http://www.pymvpa.org/generated/mvpa2.algorithms.hyperalignment.Hyperalignment.html#mvpa2.algorithms.hyperalignment.Hyperalignment
>
>ref_ds : int or None, optional
>
>Index of a dataset to use as 1st-level common space reference. If None,
>then the dataset with the maximum number of features is used.
>Constraints: (value must be in range [0, inf], and value must be
>convertible to type ‘int’), or value must be None. [Default: None]
>
>So utter is not necessarily the first (0th) dataset which is chosen...
>So you get the same results if your set ref_ds=0
>
>You could enable_ca=["chosen_ref_ds"] and then check ca.chosen_ref_ds
>on which one is chosen it you don't explicitly specify any
>-- 
>Sent from a phone which beats iPhone.  
>
>
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Could you quantify how much different?
-- 
Sent from a phone which beats iPhone.
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