tf.keras.losses.MeanSquaredError

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Computes the mean of squares of errors between labels and predictions.

Inherits From: Loss

tf.keras.losses.MeanSquaredError(
    reduction=losses_utils.ReductionV2.AUTO,
    name='mean_squared_error'
)

loss = mean(square(y_true - y_pred))

Standalone usage:

y_true = [[0., 1.], [0., 0.]]
y_pred = [[1., 1.], [1., 0.]]
# Using 'auto'/'sum_over_batch_size' reduction type.
mse = tf.keras.losses.MeanSquaredError()
mse(y_true, y_pred).numpy()
0.5

# Calling with 'sample_weight'.
mse(y_true, y_pred, sample_weight=[0.7, 0.3]).numpy()
0.25

# Using 'sum' reduction type.
mse = tf.keras.losses.MeanSquaredError(
    reduction=tf.keras.losses.Reduction.SUM)
mse(y_true, y_pred).numpy()
1.0

# Using 'none' reduction type.
mse = tf.keras.losses.MeanSquaredError(
    reduction=tf.keras.losses.Reduction.NONE)
mse(y_true, y_pred).numpy()
array([0.5, 0.5], dtype=float32)

Usage with the compile() API:

model.compile(optimizer='sgd', loss=tf.keras.losses.MeanSquaredError())

reduction Type of tf.keras.losses.Reduction to apply to loss. Default value is AUTO. AUTO indicates that the reduction option will be determined by the usage context. For almost all cases this defaults to SUM_OVER_BATCH_SIZE. When used under a tf.distribute.Strategy, except via Model.compile() and Model.fit(), using AUTO or SUM_OVER_BATCH_SIZE will raise an error. Please see this custom training tutorial for more details. name Optional name for the instance. Defaults to 'mean_squared_error'.

Methods

from_config

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@classmethod
from_config(
    config
)

Instantiates a Loss from its config (output of get_config()).

config Output of get_config().

get_config

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get_config()

Returns the config dictionary for a Loss instance.

__call__

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__call__(
    y_true, y_pred, sample_weight=None
)

Invokes the Loss instance.

y_true Ground truth values. shape = [batch_size, d0, .. dN], except sparse loss functions such as sparse categorical crossentropy where shape = [batch_size, d0, .. dN-1] y_pred The predicted values. shape = [batch_size, d0, .. dN] sample_weight Optional sample_weight acts as a coefficient for the loss. If a scalar is provided, then the loss is simply scaled by the given value. If sample_weight is a tensor of size [batch_size], then the total loss for each sample of the batch is rescaled by the corresponding element in the sample_weight vector. If the shape of sample_weight is [batch_size, d0, .. dN-1] (or can be broadcasted to this shape), then each loss element of y_pred is scaled by the corresponding value of sample_weight. (Note ondN-1: all loss functions reduce by 1 dimension, usually axis=-1.)

ValueError If the shape of sample_weight is invalid.