tf.keras.metrics.Mean

TensorFlow 1 version

View source on GitHub

Computes the (weighted) mean of the given values.

Inherits From: Metric, Layer, Module

tf.keras.metrics.Mean(
    name='mean', dtype=None
)

For example, if values is [1, 3, 5, 7] then the mean is 4. If the weights were specified as [1, 1, 0, 0] then the mean would be 2.

This metric creates two variables, total and count that are used to compute the average of values. This average is ultimately returned as mean which is an idempotent operation that simply divides total by count.

If sample_weight is None, weights default to 1. Use sample_weight of 0 to mask values.

Standalone usage:

m = tf.keras.metrics.Mean()
m.update_state([1, 3, 5, 7])
m.result().numpy()
4.0
m.reset_states()
m.update_state([1, 3, 5, 7], sample_weight=[1, 1, 0, 0])
m.result().numpy()
2.0

Usage with compile() API:

model.add_metric(tf.keras.metrics.Mean(name='mean_1')(outputs))
model.compile(optimizer='sgd', loss='mse')

Methods

reset_states

View source

reset_states()

Resets all of the metric state variables.

This function is called between epochs/steps, when a metric is evaluated during training.

result

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result()

Computes and returns the metric value tensor.

Result computation is an idempotent operation that simply calculates the metric value using the state variables.

update_state

View source

update_state(
    values, sample_weight=None
)

Accumulates statistics for computing the metric.