# tf_agents.metrics.tf_metrics.AverageEpisodeLengthMetric

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| [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metrics.py#L311-L365) |

Metric to compute the average episode length.

Inherits From: [`TFStepMetric`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/metrics/tf_metric/TFStepMetric)

    tf_agents.metrics.tf_metrics.AverageEpisodeLengthMetric(
        name='AverageEpisodeLength',
        prefix='Metrics',
        dtype=tf.float32,
        batch_size=1,
        buffer_size=10
    )

## Methods

### `call`

[View source](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metrics.py#L330-L357)

    call(
        trajectory
    )

### `init_variables`

[View source](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metric.py#L61-L75)

    init_variables()

Initializes this Metric's variables.

Should be called after variables are created in the first execution
of `__call__()`. If using graph execution, the return value should be
`run()` in a session before running the op returned by `__call__()`.
(See example above.)

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| Returns ||
|---|---|
| If using graph execution, this returns an op to perform the initialization. Under eager execution, the variables are reset to their initial values as a side effect and this function returns None. ||

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### `reset`

[View source](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metrics.py#L362-L365)

    reset()

### `result`

[View source](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metrics.py#L359-L360)

    result()

Computes and returns a final value for the metric.

### `tf_summaries`

[View source](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metric.py#L94-L126)

    tf_summaries(
        train_step=None, step_metrics=()
    )

Generates summaries against train_step and all step_metrics.

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| Args ||
|---|---|
| `train_step` | (Optional) Step counter for training iterations. If None, no metric is generated against the global step. |
| `step_metrics` | (Optional) Iterable of step metrics to generate summaries against. |

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| Returns ||
|---|---|
| A list of summaries. ||

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### `__call__`

[View source](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/metrics/tf_metric.py#L82-L92)

    __call__(
        *args, **kwargs
    )

Returns op to execute to update this metric for these inputs.

Returns None if eager execution is enabled.
Returns a graph-mode function if graph execution is enabled.

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| Args ||
|---|---|
| `*args` | <br /> <br /> |
| `**kwargs` | A mini-batch of inputs to the Metric, passed on to `call()`. |

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