Is GPU necessary for deep learning (CNN)

I am using [net, info] = trainNetwork(xTrain,tTrain, layers, opts);

error show: "There is a problem with the CUDA driver or with this GPU device. Be sure that you have a supported GPU and that the latest driver is installed."

Caused by: The CUDA driver could not be loaded. The library name used was 'nvcuda.dll'. The error was: The specified module could not be found.

Answer 1

[Kojiro Saito]

As Release Notes of Neural Network Toolbox R2016a says, deep learning functions including trainNetwork require Parallel Computing Toolbox and a CUDA-enabled NVIDIA GPU with compute capability 3.0 or higher. From 2017a, trainNetwork is supported in CPUs, as described in this link.