predictions using pylearn2 models

Question

I have trained the following CNN model using pylearn2.

h1
    Input space: Conv2DSpace(shape=(25, 150), num_channels=1, axes=('b', 0, 1, 'c'), dtype=float64)
    Total input dimension: 3750
h2
    Input space: Conv2DSpace(shape=(11, 73), num_channels=8, axes=('b', 'c', 0, 1), dtype=float64)
    Total input dimension: 6424
h3
    Input space: VectorSpace(dim=1024, dtype=float64)
    Total input dimension: 1024
h4
    Input space: VectorSpace(dim=1024, dtype=float64)
    Total input dimension: 1024
y
    Input space: VectorSpace(dim=1024, dtype=float64)
    Total input dimension: 1024

You can observe that input examples to this CNN are gray images of size 25 x150. The final number of outputs are 10, that is, the layer 'y' has an output dimension of 10.

My training dataset is created using the CSVDataset in pylearn2, and I'm able to train the model.

However, I have a problem in making predictions using this model, which I'm trying to do using the predict_csv.py file in scripts/mlp folder.

The problem is that predict_csv.py directly loads the test.csv file into a 2d matrix of 1000 x 3750 representing 1000 test examples each having 3750 pixels each. However, while predicting theano expects the input to be of the same format as input of layer 'h1'. The following error occurs:

TypeError: ('Bad input argument to theano function with name "../mlp/predict_csv.py:111"  at index 0(0-based)', 'Wrong number of dimensions: expected 4, got 2 with shape (1000, 3750).')

I guess the required format is the ('b', 0, 1, 'c') format of pylearn2.

I would really like to know how do we make this transformation from the 2d array to the above required format. Or any other way this problem could be dealt with?

score 0 · Answer 1 · answered Dec 28 '15 at 12:54

To solve my problem, I ended up manually converting the 2D set of images (1000 x 3750) to a 4D array with columns as number-of-examples, rows and columns in image, and number-of-channels (1000 x 25 x 150 x 1). It worked fine after this transformation.

I was hoping to find a pylearn2 class or function that directly served my purpose, because while training, pylearn2 is obviously making this change in space itself.

predictions using pylearn2 models

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