public static Tensor GetEvalFunction(NeuralNetworkEvalFunction lossFunction, Tensor labels, Tensor calculatedOutputs)
{
switch (lossFunction)
{
case NeuralNetworkEvalFunction.sigmoid_cross_entropy_with_logits: return(tf.reduce_mean(tf.nn.sigmoid_cross_entropy_with_logits(labels, calculatedOutputs)));
case NeuralNetworkEvalFunction.softmax_cross_entropy_with_logits: return(tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(labels, calculatedOutputs)));
case NeuralNetworkEvalFunction.softmax_cross_entropy_with_logits_v2: return(tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits_v2(labels, calculatedOutputs)));
case NeuralNetworkEvalFunction.ClassificationError: return(NetworkBuilder.ClassificationError(calculatedOutputs, labels));
case NeuralNetworkEvalFunction.MeanSquaredError: return(MeanSquaredError(labels, calculatedOutputs));
case NeuralNetworkEvalFunction.MeanAbsoluteError: return(NetworkBuilder.MeanAbsoluteError(calculatedOutputs, labels));
case NeuralNetworkEvalFunction.MeanAbsolutePercentageError: return(NetworkBuilder.MeanAbsolutePercentageError(calculatedOutputs, labels));
default:
throw new InvalidOperationException("Unexpected " + lossFunction);
}
}
//Errors with CNTK: https://github.com/Microsoft/CNTK/issues/2614
public void Train(PredictorTrainingContext ctx)
{
InitialSetup();
tf.compat.v1.disable_eager_execution();
var p = ctx.Predictor;
var nn = (NeuralNetworkSettingsEntity)p.AlgorithmSettings;
Tensor inputPlaceholder = tf.placeholder(tf.float32, new[] { -1, ctx.InputCodifications.Count }, "inputPlaceholder");
Tensor outputPlaceholder = tf.placeholder(tf.float32, new[] { -1, ctx.OutputCodifications.Count }, "outputPlaceholder");
Tensor currentTensor = inputPlaceholder;
nn.HiddenLayers.ForEach((layer, i) =>
{
currentTensor = NetworkBuilder.DenseLayer(currentTensor, layer.Size, layer.Activation, layer.Initializer, p.Settings.Seed ?? 0, "hidden" + i);
});
Tensor output = NetworkBuilder.DenseLayer(currentTensor, ctx.OutputCodifications.Count, nn.OutputActivation, nn.OutputInitializer, p.Settings.Seed ?? 0, "output");
Tensor calculatedOutput = tf.identity(output, "calculatedOutput");
Tensor loss = NetworkBuilder.GetEvalFunction(nn.LossFunction, outputPlaceholder, calculatedOutput);
Tensor accuracy = NetworkBuilder.GetEvalFunction(nn.EvalErrorFunction, outputPlaceholder, calculatedOutput);
// prepare for training
Optimizer optimizer = NetworkBuilder.GetOptimizer(nn);
Operation trainOperation = optimizer.minimize(loss);
Random rand = p.Settings.Seed == null ?
new Random() :
new Random(p.Settings.Seed.Value);
var(training, validation) = ctx.SplitTrainValidation(rand);
var minibachtSize = nn.MinibatchSize;
var numMinibatches = nn.NumMinibatches;
Stopwatch sw = Stopwatch.StartNew();
List <FinalCandidate> candidate = new List <FinalCandidate>();
var config = new ConfigProto
{
IntraOpParallelismThreads = 1,
InterOpParallelismThreads = 1,
LogDevicePlacement = true
};
ctx.ReportProgress($"Deleting Files");
var dir = PredictorDirectory(ctx.Predictor);
if (Directory.Exists(dir))
{
Directory.Delete(dir, true);
}
Directory.CreateDirectory(dir);
ctx.ReportProgress($"Starting training...");
var saver = tf.train.Saver();
using (var sess = tf.Session(config))
{
sess.run(tf.global_variables_initializer());
for (int i = 0; i < numMinibatches; i++)
{
using (HeavyProfiler.Log("MiniBatch", () => i.ToString()))
{
var trainMinibatch = 0.To(minibachtSize).Select(_ => rand.NextElement(training)).ToList();
var inputValue = CreateNDArray(ctx, trainMinibatch, ctx.InputCodifications.Count, ctx.InputCodificationsByColumn);
var outputValue = CreateNDArray(ctx, trainMinibatch, ctx.OutputCodifications.Count, ctx.OutputCodificationsByColumn);
using (HeavyProfiler.Log("TrainMinibatch", () => i.ToString()))
{
sess.run(trainOperation,
(inputPlaceholder, inputValue),
(outputPlaceholder, outputValue));
}
if (ctx.StopTraining)
{
p = ctx.Predictor = ctx.Predictor.ToLite().RetrieveAndRemember();
}
var isLast = numMinibatches - nn.BestResultFromLast <= i;
if (isLast || (i % nn.SaveProgressEvery) == 0 || ctx.StopTraining)
{
float loss_val;
float accuracy_val;
using (HeavyProfiler.Log("EvalTraining", () => i.ToString()))
{
(loss_val, accuracy_val) = sess.run((loss, accuracy),
(inputPlaceholder, inputValue),
(outputPlaceholder, outputValue));
}
var ep = new EpochProgress
{
Ellapsed = sw.ElapsedMilliseconds,
Epoch = i,
TrainingExamples = i * minibachtSize,
LossTraining = loss_val,
AccuracyTraining = accuracy_val,
LossValidation = null,
AccuracyValidation = null,
};
ctx.ReportProgress($"Training Minibatches Loss:{loss_val} / Accuracy:{accuracy_val}", (i + 1) / (decimal)numMinibatches);
ctx.Progresses.Enqueue(ep);
if (isLast || (i % nn.SaveValidationProgressEvery) == 0 || ctx.StopTraining)
{
using (HeavyProfiler.LogNoStackTrace("EvalValidation"))
{
var validateMinibatch = 0.To(minibachtSize).Select(_ => rand.NextElement(validation)).ToList();
var inputValValue = CreateNDArray(ctx, validateMinibatch, ctx.InputCodifications.Count, ctx.InputCodificationsByColumn);
var outputValValue = CreateNDArray(ctx, validateMinibatch, ctx.OutputCodifications.Count, ctx.OutputCodificationsByColumn);
(loss_val, accuracy_val) = sess.run((loss, accuracy),
(inputPlaceholder, inputValValue),
(outputPlaceholder, outputValValue));
ep.LossValidation = loss_val;
ep.AccuracyValidation = accuracy_val;
}
}
var progress = ep.SaveEntity(ctx.Predictor);
if (isLast || ctx.StopTraining)
{
Directory.CreateDirectory(TrainingModelDirectory(ctx.Predictor, i));
var save = saver.save(sess, Path.Combine(TrainingModelDirectory(ctx.Predictor, i), ModelFileName));
using (HeavyProfiler.LogNoStackTrace("FinalCandidate"))
{
candidate.Add(new FinalCandidate
{
ModelIndex = i,
ResultTraining = new PredictorMetricsEmbedded {
Accuracy = progress.AccuracyTraining, Loss = progress.LossTraining
},
ResultValidation = new PredictorMetricsEmbedded {
Accuracy = progress.AccuracyValidation, Loss = progress.LossValidation
},
});
}
}
}
if (ctx.StopTraining)
{
break;
}
}
}
}
var best = candidate.WithMin(a => a.ResultValidation.Loss !.Value);
p.ResultTraining = best.ResultTraining;
p.ResultValidation = best.ResultValidation;
var files = Directory.GetFiles(TrainingModelDirectory(ctx.Predictor, best.ModelIndex));
p.Files.AddRange(files.Select(p => new Entities.Files.FilePathEmbedded(PredictorFileType.PredictorFile, p)));
using (OperationLogic.AllowSave <PredictorEntity>())
p.Save();
}
