error using nnet.inter​nal.cnn.la​yer.util.f​ullyConnec​tedGPUImag​eStrategy

disp('Track: network training section begins!')

trainOpt = trainingOptions('adam', ...

'InitialLearnRate',options.learningRate, ...

'LearnRateSchedule','piecewise', ...

'LearnRateDropFactor',options.dropFactor, ...

'LearnRateDropPeriod',options.learnRateSch, ...

'L2Regularization',options.weightDecay, ...

'MaxEpochs',options.maxNumEpochs, ...

'MiniBatchSize',options.batchSize, ...

'Shuffle','every-epoch', ...

'ValidationData',dataPrep.val, ...

'ValidationFrequency',options.valFreq, ...

'ExecutionEnvironment','gpu', ...

'ValidationPatience', 10, ... % Disables automatic training break-off

'Plots','none');

gpuDevice(1)

[trainedNet, trainingInfo] = trainNetwork(dataPrep.train{1,:}, dataPrep.train{2,:}, net, trainOpt);

save([options.netSaveDir,'net_ant=',num2str(options.ch(i)),'_pilot=',num2str(options.pilotSize)], 'trainedNet')

% show NMSE on validation dataset

nanLoc = isnan(trainingInfo.ValidationLoss);

valNMSE = trainingInfo.ValidationLoss(~nanLoc);

options.valNMSE = valNMSE;

R_NMSE(j, i) = options.valNMSE(end);