[pymvpa] ChainMapper

[patrik andersson]

Hi,

I have a question regarding mappers.
To follow one of your examples, lets say we have;

In [8]: ds = dataset_wizard(np.ones((5, 4, 3)))

In [9]: ds.a.mapper
Out[9]: FlattenMapper(shape=(4, 3), auto_train=True)

Now we select a subset;

In [10]: ds = ds[:, [1,3,4]]

In [11]: ds.a.mapper
Out[11]: ChainMapper(nodes=[FlattenMapper(shape=(4, 3),
auto_train=True), StaticFeatureSelection(dshape=(12,), oshape=(3,),
slicearg=[1, 3, 4])])



So far, so good.
If we now select a subset of this;

In [12]: ds = ds[:, [0,1]]

In [13]: ds.a.mapper
Out[13]: ChainMapper(nodes=[FlattenMapper(shape=(4, 3),
auto_train=True), StaticFeatureSelection(dshape=(12,), oshape=(3,),
slicearg=array([1, 3]))])

In [14]: ds.shape
Out[14]: (5, 2)

Is the new StaticFeatureSelection not in the ChainMapper, or is it
just a display issue?

Cheers,
Patrik