<br />

|---|
| [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/history.py#L5-L42) |

Callback that records events into a `History` object.

Inherits From: [`Callback`](https://www.tensorflow.org/api_docs/python/tf/keras/callbacks/Callback)

    tf.keras.callbacks.History()

This callback is automatically applied to
every Keras model. The `History` object
gets returned by the `fit()` method of models.

#### Example:

    model = Sequential([layers.Dense(10)])
    model.compile(SGD(), loss='mse')
    history = model.fit(np.arange(100).reshape(5, 20), np.zeros(5),
                        epochs=10, verbose=1)
    print(history.params)
    {'verbose': 1, 'epochs': 10, 'steps': 1}
    # check the keys of history object
    print(history.history.keys())
    dict_keys(['loss'])

<br />

<br />

<br />

| ## Attributes ||
|---|---|
| `model` | <br /> <br /> |

<br />

## Methods

### `on_batch_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L102-L104)

    on_batch_begin(
        batch, logs=None
    )

A backwards compatibility alias for `on_train_batch_begin`.

### `on_batch_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L106-L108)

    on_batch_end(
        batch, logs=None
    )

A backwards compatibility alias for `on_train_batch_end`.

### `on_epoch_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L110-L121)

    on_epoch_begin(
        epoch, logs=None
    )

Called at the start of an epoch.

Subclasses should override for any actions to run. This function should
only be called during TRAIN mode.

<br />

<br />

<br />

| Args ||
|---|---|
| `epoch` | Integer, index of epoch. |
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_epoch_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/history.py#L34-L42)

    on_epoch_end(
        epoch, logs=None
    )

Called at the end of an epoch.

Subclasses should override for any actions to run. This function should
only be called during TRAIN mode.

<br />

<br />

<br />

| Args ||
|---|---|
| `epoch` | Integer, index of epoch. |
| `logs` | Dict, metric results for this training epoch, and for the validation epoch if validation is performed. Validation result keys are prefixed with `val_`. For training epoch, the values of the `Model`'s metrics are returned. Example: `{'loss': 0.2, 'accuracy': 0.7}`. |

<br />

### `on_predict_batch_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L211-L225)

    on_predict_batch_begin(
        batch, logs=None
    )

Called at the beginning of a batch in `predict` methods.

Subclasses should override for any actions to run.

Note that if the `steps_per_execution` argument to `compile` in
`Model` is set to `N`, this method will only be called every
`N` batches.

<br />

<br />

<br />

| Args ||
|---|---|
| `batch` | Integer, index of batch within the current epoch. |
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_predict_batch_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L227-L240)

    on_predict_batch_end(
        batch, logs=None
    )

Called at the end of a batch in `predict` methods.

Subclasses should override for any actions to run.

Note that if the `steps_per_execution` argument to `compile` in
`Model` is set to `N`, this method will only be called every
`N` batches.

<br />

<br />

<br />

| Args ||
|---|---|
| `batch` | Integer, index of batch within the current epoch. |
| `logs` | Dict. Aggregated metric results up until this batch. |

<br />

### `on_predict_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L288-L297)

    on_predict_begin(
        logs=None
    )

Called at the beginning of prediction.

Subclasses should override for any actions to run.

<br />

<br />

<br />

| Args ||
|---|---|
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_predict_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L299-L308)

    on_predict_end(
        logs=None
    )

Called at the end of prediction.

Subclasses should override for any actions to run.

<br />

<br />

<br />

| Args ||
|---|---|
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_test_batch_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L174-L191)

    on_test_batch_begin(
        batch, logs=None
    )

Called at the beginning of a batch in `evaluate` methods.

Also called at the beginning of a validation batch in the `fit`
methods, if validation data is provided.

Subclasses should override for any actions to run.

Note that if the `steps_per_execution` argument to `compile` in
`Model` is set to `N`, this method will only be called every
`N` batches.

<br />

<br />

<br />

| Args ||
|---|---|
| `batch` | Integer, index of batch within the current epoch. |
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_test_batch_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L193-L209)

    on_test_batch_end(
        batch, logs=None
    )

Called at the end of a batch in `evaluate` methods.

Also called at the end of a validation batch in the `fit`
methods, if validation data is provided.

Subclasses should override for any actions to run.

Note that if the `steps_per_execution` argument to `compile` in
`Model` is set to `N`, this method will only be called every
`N` batches.

<br />

<br />

<br />

| Args ||
|---|---|
| `batch` | Integer, index of batch within the current epoch. |
| `logs` | Dict. Aggregated metric results up until this batch. |

<br />

### `on_test_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L265-L274)

    on_test_begin(
        logs=None
    )

Called at the beginning of evaluation or validation.

Subclasses should override for any actions to run.

<br />

<br />

<br />

| Args ||
|---|---|
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_test_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L276-L286)

    on_test_end(
        logs=None
    )

Called at the end of evaluation or validation.

Subclasses should override for any actions to run.

<br />

<br />

<br />

| Args ||
|---|---|
| `logs` | Dict. Currently the output of the last call to `on_test_batch_end()` is passed to this argument for this method but that may change in the future. |

<br />

### `on_train_batch_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L139-L155)

    on_train_batch_begin(
        batch, logs=None
    )

Called at the beginning of a training batch in `fit` methods.

Subclasses should override for any actions to run.

Note that if the `steps_per_execution` argument to `compile` in
`Model` is set to `N`, this method will only be called every
`N` batches.

<br />

<br />

<br />

| Args ||
|---|---|
| `batch` | Integer, index of batch within the current epoch. |
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_train_batch_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L157-L172)

    on_train_batch_end(
        batch, logs=None
    )

Called at the end of a training batch in `fit` methods.

Subclasses should override for any actions to run.

Note that if the `steps_per_execution` argument to `compile` in
`Model` is set to `N`, this method will only be called every
`N` batches.

<br />

<br />

<br />

| Args ||
|---|---|
| `batch` | Integer, index of batch within the current epoch. |
| `logs` | Dict. Aggregated metric results up until this batch. |

<br />

### `on_train_begin`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/history.py#L31-L32)

    on_train_begin(
        logs=None
    )

Called at the beginning of training.

Subclasses should override for any actions to run.

<br />

<br />

<br />

| Args ||
|---|---|
| `logs` | Dict. Currently no data is passed to this argument for this method but that may change in the future. |

<br />

### `on_train_end`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L253-L263)

    on_train_end(
        logs=None
    )

Called at the end of training.

Subclasses should override for any actions to run.

<br />

<br />

<br />

| Args ||
|---|---|
| `logs` | Dict. Currently the output of the last call to `on_epoch_end()` is passed to this argument for this method but that may change in the future. |

<br />

### `set_model`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L74-L75)

    set_model(
        model
    )

### `set_params`

[View source](https://github.com/keras-team/keras/tree/v3.15.1/keras/src/callbacks/callback.py#L71-L72)

    set_params(
        params
    )