tf.keras.metrics.Accuracy

Calculates how often predictions matches labels.

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Main aliases

tf.metrics.Accuracy

Compat aliases for migration

See Migration guide for more details.

tf.compat.v1.keras.metrics.Accuracy

tf.keras.metrics.Accuracy(
    name='accuracy', dtype=None
)

For example, if y_true is [1, 2, 3, 4] and y_pred is [0, 2, 3, 4] then the accuracy is 3/4 or .75. If the weights were specified as [1, 1, 0, 0] then the accuracy would be 1/2 or .5.

This metric creates two local variables, total and count that are used to compute the frequency with which y_pred matches y_true. This frequency is ultimately returned as binary accuracy: 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.

Usage:

m = tf.keras.metrics.Accuracy()
_ = m.update_state([1, 2, 3, 4], [0, 2, 3, 4])
m.result().numpy()
0.75
m.reset_states()
_ = m.update_state([1, 2, 3, 4], [0, 2, 3, 4], sample_weight=[1, 1, 0, 0])
m.result().numpy()
0.5

Usage with tf.keras API:

model = tf.keras.Model(inputs, outputs)
model.compile('sgd', loss='mse', metrics=[tf.keras.metrics.Accuracy()])

Args
fn	The metric function to wrap, with signature fn(y_true, y_pred, **kwargs).
name	(Optional) string name of the metric instance.
dtype	(Optional) data type of the metric result.
**kwargs	The keyword arguments that are passed on to fn.

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

View source

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(
    y_true, y_pred, sample_weight=None
)

Accumulates metric statistics.

y_true and y_pred should have the same shape.

Args
y_true	The ground truth values.
y_pred	The predicted values.
sample_weight	Optional weighting of each example. Defaults to 1. Can be a Tensor whose rank is either 0, or the same rank as y_true, and must be broadcastable to y_true.

Returns
Update op.