As an AI language model, I don't have a context to decide what task you want to achieve by importing these modules. So, I am providing you some information on these modules. These modules are PyTorch built-in modules for building and training deep learning models. torch.nn module provides various classes and functions for building neural networks. For example, it provides classes for defining layers such as Linear, Conv2d, LSTM, etc. It also provides classes for defining activation functions, loss functions, and more. torch.nn.functional module provides various functions that can be used inside the neural network layers. For example, it provides functions for activation functions like ReLU, sigmoid, etc., pooling functions like max pooling, convolution functions, and more. torch.optim module provides various optimization algorithms for training deep learning models. For example, it provides classes for optimization algorithms like Stochastic Gradient Descent (SGD), Adam, Adagrad, etc. In summary, these modules are essential for building and training deep learning models using PyTorch.