[pymvpa] Hyperalignment: "For now do not handle invariant in time datasets"

[Swaroop Guntupalli]

Hi Katja,

It looks the code is checking if variance/sum of squares of time
series in your data is practically zero, and raising that error.
Check if all your input datasets have non-zero variance in all voxels.

Best,
Swaroop

On Mon, Nov 13, 2017 at 4:41 AM, Müller, K. (Katja)
<K.Muller at psych.ru.nl> wrote:
> Dear all,
>
> It would be great if somebody has any kind of information about what causes this issue, and ways to solve it.
>
> I am running hyperalignment ROI-by-ROI on 3 subjects. It works on every ROI except the largest one with ~28k voxels (the dataset has 53k voxels in total), where it fails with the error message:
> "For now do not handle invariant in time datasets"
>
> It was suggested earlier (similar mailing list question from 2013) to remove invariant voxels to solve this issue. I tried both remove_invariant_features() and my own code for this, but the behaviour and error message did not change.
>
> My datasets are inside a standard Python list.
>
>        train_pymv_datasets = [mvpa2.datasets.Dataset(dataset) for dataset in roi0_train_data]
>        hyperalign_fit = mvpa2.algorithms.hyperalignment.Hyperalignment()(train_pymv_datasets)
>
> This is what I get when calling the second line:
>
> init_dgesdd failed init
> init_dgesdd failed init
> init_dgesdd failed init
> init_dgesdd failed init
> Traceback (most recent call last):
>  File "save_hyperaligned_subject.py", line 77, in <module>
>    hyperalign_fit = mvpa2.algorithms.hyperalignment.Hyperalignment()(train_pymv_datasets)
>  File ".../anaconda2/lib/python2.7/site-packages/mvpa2/algorithms/hyperalignment.py", line 339, in __call__
>    self.train(datasets)
>  File ".../anaconda2/lib/python2.7/site-packages/mvpa2/algorithms/hyperalignment.py", line 319, in train
>    residuals)
>  File ".../anaconda2/lib/python2.7/site-packages/mvpa2/algorithms/hyperalignment.py", line 483, in _level2
>    m.train(ds_new)
>  File ".../anaconda2/lib/python2.7/site-packages/mvpa2/base/learner.py", line 137, in train
>    self._train(ds)
>  File ".../anaconda2/lib/python2.7/site-packages/mvpa2/mappers/procrustean.py", line 123, in _train
>    raise ValueError, "For now do not handle invariant in time datasets"
> ValueError: For now do not handle invariant in time datasets
>
>
> I looked up the respective code section in procrustean.py, but am not sure what the code is checking for there.
>
>
> Best regards from the Netherlands,
> Katja Müller
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