Source code for mindspore.train.callback._lambda_callback

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"""Lambda Callback class."""

from ._callback import Callback


[文档]class LambdaCallback(Callback): """ Callback for creating simple, custom callbacks. This callback is constructed with anonymous functions that will be called at the appropriate time (during `mindspore.Model.{train | eval}`). Note that each stage of callbacks expects one positional arguments: `run_context`. Note: This is an experimental interface that is subject to change or deletion. Args: epoch_begin (Function): called at the beginning of every epoch. epoch_end (Function): called at the end of every epoch. step_begin (Function): called at the beginning of every batch. step_end (Function): called at the end of every batch. begin (Function): called at the beginning of model train/eval. end (Function): called at the end of model train/eval. Examples: >>> import numpy as np >>> import mindspore.dataset as ds >>> from mindspore.train.callback import LambdaCallback >>> from mindspore import Model, nn >>> data = {"x": np.float32(np.random.rand(64, 10)), "y": np.random.randint(0, 5, (64,))} >>> train_dataset = ds.NumpySlicesDataset(data=data).batch(32) >>> net = nn.Dense(10, 5) >>> crit = nn.SoftmaxCrossEntropyWithLogits(sparse=True, reduction='mean') >>> opt = nn.Momentum(net.trainable_params(), 0.01, 0.9) >>> lambda_callback = LambdaCallback(epoch_end= ... lambda run_context: print("loss: ", run_context.original_args().net_outputs)) >>> model = Model(network=net, optimizer=opt, loss_fn=crit, metrics={"recall"}) >>> model.train(2, train_dataset, callbacks=[lambda_callback]) loss: 1.6127687 loss: 1.6106578 """ def __init__(self, epoch_begin=None, epoch_end=None, step_begin=None, step_end=None, begin=None, end=None): super(LambdaCallback, self).__init__() self.epoch_begin = epoch_begin if epoch_begin else lambda run_context: None self.epoch_end = epoch_end if epoch_end else lambda run_context: None self.step_begin = step_begin if step_begin else lambda run_context: None self.step_end = step_end if step_end else lambda run_context: None self.begin = begin if begin else lambda run_context: None self.end = end if end else lambda run_context: None