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Recently, I did a session at local user group in Ljubljana, Slovenija, where I introduced the new algorithms that are available with MicrosoftML package for Microsoft R Server 9.0.3.

For dataset, I have used two from (still currently) running sessions from Kaggle. In the last part, I did image detection and prediction of MNIST dataset and compared the performance and accuracy between.

MNIST Handwritten digit database is available here.

Starting off with rxNeuralNet, we have to build a NET# model or Neural network to work it’s way.

Model for Neural network:

const { T = true; F = false; } input Picture [28, 28]; hidden C1 [5 * 13^2] from Picture convolve { InputShape = [28, 28]; UpperPad = [ 1, 1]; KernelShape = [ 5, 5]; Stride = [ 2, 2]; MapCount = 5; } hidden C2 [50, 5, 5] from C1 convolve { InputShape = [ 5, 13, 13]; KernelShape = [ 1, 5, 5]; Stride = [ 1, 2, 2]; Sharing = [ F, T, T]; MapCount = 10; } hidden H3 [100] from C2 all; // Output layer definition. output Result [10] from H3 all;

Once we have this, we can work out with rxNeuralNet algorithm:

model_DNN_GPU <- rxNeuralNet(label ~. ,data = dataTrain ,type = "multi" ,numIterations = 10 ,normalize = "no" #,acceleration = "gpu" #enable this if you have CUDA driver ,miniBatchSize = 64 #set to 1 else set to 64 if you have CUDA driver problem ,netDefinition = netDefinition ,optimizer = sgd(learningRate = 0.1, lRateRedRatio = 0.9, lRateRedFreq = 10) )

Then do the prediction and calculate accuracy matrix:

DNN_GPU_score <- rxPredict(model_DNN_GPU, dataTest, extraVarsToWrite = "label") sum(Score_DNN$Label == DNN_GPU_score$PredictedLabel)/dim(DNN_GPU_score)[1]

Accuracy for this model is:

[1] 0.9789

When working with H2O package, the following code was executed to get same paramethers for Neural network:

model_h20 <- h2o.deeplearning(x = 2:785 ,y = 1 # label for label ,training_frame = train_h2o ,activation = "RectifierWithDropout" ,input_dropout_ratio = 0.2 # % of inputs dropout ,hidden_dropout_ratios = c(0.5,0.5) # % for nodes dropout ,balance_classes = TRUE ,hidden = c(50,100,100) ,momentum_stable = 0.99 ,nesterov_accelerated_gradient = T # use it for speed ,epochs = 15)

When results of test dataset against the learned model is executed:

h2o.confusionMatrix(model_h20) 100-(416/9978)*100

the result is confusion matrix for accuracy of predicted values with value of:

# [1] 95.83083

For comparison, I have added xgBoost (eXtrem Gradient Boosting), but this time, I will not focus on this one.

Time comparison against the packages (in seconds), from left to right are: H20, MicrosoftML with GPU acceleration, MicrosoftML without GPU acceleration and xgBoost.

As for the accuracy of the trained model, here are results (based on my tests):

MicrosoftML – Neural Network – 97,8%

H20 – Deep Learning – 95,3 %

xgBoost – 94,9 %

As always, code and dataset are available at GitHub.

Happy R-ing

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