[pymvpa] Fwd: Searchlight Accuracy Decimal Precision Issue

Yaroslav Halchenko yoh at onerussian.com
Thu May 17 12:21:59 BST 2018

Please share output of 

print data.summary()

Right before your give it to searchlight

On May 17, 2018 3:59:39 AM EDT, Tyler Adkins <adkinsty at umich.edu> wrote:
>I am running a searchlight analysis and I encountered a strange feature
>of the resulting classification accuracies. All of the non-zero
>accuracies have only one decimal point of precision (e.g., .5, .6.,
>.7., .8, etc.). Unfortunately, I'm not able to figure out what aspect
>of my code is leading to this truncating or rounding of the accuracies.
>I attached my code below, but here's some information about my
>analysis. Please let me know if you would like me to provide any other
>information about the analysis. My searchlight repeats a 10-fold
>cross-validation procedure for a linear support vector classifier with
>default parameters. The number of classes is 2 and the total number of
>samples is roughly 240. The sequence of samples is randomized and
>balanced so that there is an equal number of instances of the two
>classes in each of the 10 folds. The searchlight also applies the
>mean_sample() postproc so that the resulting classification accuracies
>are averaged over the cross-validation folds.
>As mentioned above, I'm unsure what about my script is leading to the
>rounding/truncating of the accuracies. Most of the script is copied
>from one of the PyMVPA searchlight tutorials, which further adds to my
>confusion, since the tutorial searchlight clearly outputs accuracies
>with greater than 1-decimal precision.
>I would greatly appreciate any ideas you might have about what could be
>causing this problem or how to address it.
>Thank you for your time.
>Tyler Adkins
>PhD Pre-candidate | Cognition and Cognitive Neuroscience
>University of Michigan Department of Psychology
>530 Church Street Ann Arbor, MI 48109-1043
>Email: adkinsty at umich.edu
>Office: 3036 East Hall
>Lab: B018 East Hall

Sent from a phone which beats iPhone.
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