Tensorflow訓練迴圈

2021-09-13 23:50:25 字數 3391 閱讀 2658

def fit_loop(model,

inputs,

targets,

sample_weights=none,

class_weight=none,

val_inputs=none,

val_targets=none,

val_sample_weights=none,

batch_size=none,

epochs=1,

verbose=1,

callbacks=none,

shuffle=true,

initial_epoch=0,

steps_per_epoch=none,

# convert training inputs to an eageriterator

inputs, steps_per_epoch = training_utils.convert_to_iterator(

x=inputs,

y=targets,

sample_weights=sample_weights,

batch_size=batch_size,

steps_per_epoch=steps_per_epoch,

epochs=epochs,

shuffle=shuffle)

# 迭代每個週期

for epoch in range(initial_epoch, epochs):

iterator_fit_loop(

model,

inputs,

class_weight,

steps_per_epoch=steps_per_epoch,

epoch_logs=epoch_logs,

val_inputs=val_inputs,

val_targets=val_targets,

val_sample_weights=val_sample_weights,

epochs=epochs,

verbose=verbose,

callbacks=callbacks,

validation_steps=validation_steps,

do_validation=do_validation,

batch_size=batch_size)

乙個迭代週期

def iterator_fit_loop(model,inputs,class_weight,steps_per_epoch,epoch_logs,val_inputs=none,val_targets=none,val_sample_weights=none,epochs=1,verbose=1,callbacks=none,validation_steps=none,do_validation=false,batch_size=none):

# 在乙個週期中,遍歷訓練 dataset 中的每個樣本,並獲取樣本的特徵 (x) 和標籤 (y)。

for step_index in range(steps_per_epoch):

next_element = inputs.get_next()

x, y, sample_weights = next_element

outs, loss, loss_metrics, masks = _process_single_batch(

model, x, y, sample_weights=sample_weights, training=true)

def _process_single_batch(model, inputs, targets, sample_weights=none, training=false):

outs, loss, loss_metrics, masks = _model_loss(model, inputs, targets, sample_weights=sample_weights, training=training)

grads = tape.gradient(loss, model._collected_trainable_weights)

def _model_loss(model, inputs, targets, sample_weights=none, training=false):

outs = model.call(inputs, **kwargs)

for i, loss_fn in enumerate(model.loss_functions):

weighted_masked_fn = training_utils.weighted_masked_objective(loss_fn)

output_loss = weighted_masked_fn(targets[i], outs[i], weights, mask=mask)

loss_weight = model.loss_weights_list[i]

total_loss += loss_weight * output_loss

return outs, total_loss, loss_metrics, masks

def _eager_metrics_fn(model, outputs, targets, sample_weights=none, masks=none):

metric_results = model._handle_metrics(

outputs, targets=targets, sample_weights=sample_weights, masks=masks)

1.迭代每個週期。通過一次資料集即為乙個週期。

2.在乙個週期中,遍歷訓練 dataset 中的每個樣本,並獲取樣本的特徵 (x) 和標籤 (y)。

for step_index in range(steps_per_epoch):

next_element = inputs.get_next()

x, y, sample_weights = next_element

3.根據樣本的特徵進行**,並比較**結果和標籤。衡量**結果的不準確性,並使用所得的值計算模型的損失和梯度。

outs, loss, loss_metrics, masks = _model_loss(model, inputs, targets, sample_weights=sample_weights, training=training)

grads = tape.gradient(loss, model._collected_trainable_weights)

5.跟蹤一些統計資訊以進行視覺化。

metrics_results = _eager_metrics_fn(

model, outs, y, sample_weights=sample_weights, masks=masks)

6.對每個週期重複執行以上步驟。

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