class paddle.fluid.dygraph.Tracer[source]

Tracer is used to execute and record the operators executed, to construct the computation graph in dygraph model. Tracer has two mode, train_mode and eval_mode. In train_mode, Tracer would add backward network automatically and perform AutoGrad by method loss.backward(). In eval_mode, Tracer would not add backward network.

This is a low level API, users don’t need to use it directly.