some examples of pytorch syntax (contd for another examplethe two layers in the following neural network (from pytorch tutorialare declared in lines (aand (band how the network is connected is declared in forward(in line (cwe push data through the network by calling model(xin line (dbut we never call forward(how is one supposed to understand thisclass twolayernet(torch nn module)def __init__(selfd_inhd_out)torch nn module __init__self self linear torch nn linear(d_inhself linear torch nn linear(hd_outdef forward(selfx)h_relu self linear (xclamp(min= using clamp(for nn relu y_pred self linear (h_relureturn y_pred nd_inhd_out torch randn(nd_inn is batch size torch randn(nd_outmodel twolayernet(d_inhd_outcriterion torch nn mseloss(reduction='sum'optimizer torch optim sgd(model parameters()lr= - for in range( )y_pred model(xloss criterion(y_predyoptimizer zero_grad(loss backward(optimizer step(purdue university #( #( #( #(