MLlib’s tooling for tuning the hyperparameters from Keras model and tensors (no images)

[anamf]

Hi Team, Is there any plan to extend functionality so that we are able to use MLlib's tooling for tunning the hyperparameters of a keras model in e.g. numeric data (i.e. no images)? I believe I would need the equivalent to the KerasImageFileEstimator but for tensors. Is there an easy workaround in the meantime? Best, Ana

[cdiogo1979]

I was able to get a model being trained by creating this class which overrides the KerasImageFileEstimator class

I see the model being trained in the worker and all its fine. But for some reason the returned model has a very bad accuracy eventough in the logs of the worker , the validation accuracy was very good.

Give it a try , maybe you are lucky

from sparkdl.param import (

keyword_only, CanLoadImage, HasKerasModel, HasKerasOptimizer, HasKerasLoss, HasOutputMode,

HasInputCol, HasLabelCol, HasOutputCol)

from sparkdl.transformers.keras_tensor import KerasTransformer from sparkdl.estimators.keras_image_file_estimator import KerasImageFileEstimator import sparkdl.utils.keras_model as kmutil

class generalKerasEstimator(KerasImageFileEstimator):

def _getNumpyFeaturesAndLabels(self, dataset):
    
    image_uri_col = self.getInputCol()

    input_col = self.getInputCol()

    label_col = None

    if self.isDefined(self.labelCol) and self.getLabelCol() != "":

        label_col = self.getLabelCol()

    tmp_image_col = self._loadedImageCol()

    image_df = dataset.select(input_col,label_col)



    # Extract features

    localFeatures = []

    rows = image_df.collect()

    for row in rows:

        feat = row[input_col]

        features = array(feat)

        localFeatures.append(features)



    if not localFeatures:  # NOTE(phi-dbq): pep-8 recommended against testing 0 == len(array)

        raise ValueError("Cannot extract any feature from dataset!")

    X = np.stack(localFeatures, axis=0)


    # Extract labels

    y = None

    if label_col is not None:

        label_schema = image_df.schema[label_col]

        label_dtype = label_schema.dataType

        #assert isinstance(label_dtype, spla.VectorUDT), \

        #            "must encode labels in one-hot vector format, but got {}".format(label_dtype)



    localLabels = []

    for row in rows:

        try:

            _keras_label = row[label_col]

        except ValueError:

            raise ValueError("Cannot extract encoded label array")

        localLabels.append(_keras_label)


    if not localLabels:

        raise ValueError("Failed to load any labels from dataset, but labels are required")

    y = np.stack(localLabels, axis=0)

    assert y.shape[0] == X.shape[0], "number of features {} != number of labels {}".format(X.shape[0], y.shape[0])


    return X, y

   
def _collectModels(self, kerasModelBytesRDD):

    """

    Collect Keras models on workers to MLlib Models on the driver.

    :param kerasModelBytesRDD: RDD of (param_map, model_bytes) tuples

    :return: generator of (index, MLlib model) tuples

    """
    

    for (i, param_map, model_bytes) in kerasModelBytesRDD.collect():

        model_filename = kmutil.bytes_to_h5file(model_bytes)
        
        print(i,model_filename,param_map)

        yield i, self._copyValues(KerasTransformer(modelFile=model_filename),

                                  extra=param_map)