tf.keras.metrics.CosineSimilarity

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Computes the cosine similarity between the labels and predictions.

tf.keras.metrics.CosineSimilarity(
    name='cosine_similarity', dtype=None, axis=-1
)

cosine similarity = (a . b) / ||a|| ||b|| Cosine Similarity

For example, if y_true is [0, 1, 1], and y_pred is [1, 0, 1], the cosine similarity is 0.5.

This metric keeps the average cosine similarity between predictions and labels over a stream of data.

Usage:

m = tf.keras.metrics.CosineSimilarity(axis=1)
m.update_state([[0., 1.], [1., 1.]], [[1., 0.], [1., 1.]])
# l2_norm(y_true) = [[0., 1.], [1./1.414], 1./1.414]]]
# l2_norm(y_pred) = [[1., 0.], [1./1.414], 1./1.414]]]
# l2_norm(y_true) . l2_norm(y_pred) = [[0., 0.], [0.5, 0.5]]
# result = mean(sum(l2_norm(y_true) . l2_norm(y_pred), axis=1))
       = ((0. + 0.) +  (0.5 + 0.5)) / 2

print('Final result: ', m.result().numpy())  # Final result: 0.5

Usage with tf.keras API:

model = tf.keras.Model(inputs, outputs)
model.compile(
    'sgd',
    loss='mse',
    metrics=[tf.keras.metrics.CosineSimilarity(axis=1)])

Args:

• name: (Optional) string name of the metric instance.
• dtype: (Optional) data type of the metric result.
• axis: (Optional) Defaults to -1. The dimension along which the cosine similarity is computed.

Methods

reset_states

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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

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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.