MATLAB: How is it possible to use a validation set with a LSTM

deep learningDeep Learning Toolboxlstmneural networkstraining networktrainnetworkvalidation set

When I try to use the Validation set with a LSTM layer, it shows the following error:
options = trainingOptions('adam', ...
'ExecutionEnvironment','gpu', ...
'GradientThreshold',1, ...
'MaxEpochs',maxEpochs, ...
'ValidationData',{XTest,YTest},...
'MiniBatchSize',miniBatchSize, ...
'LearnRateSchedule','piecewise', ...
'SequenceLength','longest', ...
'Shuffle','never', ...
'Verbose',0, ...
'Plots','training-progress');
net = trainNetwork(XTrain,categorical(YTrain),layers,options);
Error:
Training with validation data is not supported for networks with LSTM layers.
Is there another way to use the Validation set during the training of the network?

Best Answer

It's ugly, but if you use Checkpoints, then you can use an OutputFcn to (once per epoch) load the network from a checkpoint and run it against your validation data. It isn't very efficient, but it's okay if you're only doing it once per epoch. You won't get it on the training plot of course.