tfa.losses.SparsemaxLoss

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Sparsemax loss function.

tfa.losses.SparsemaxLoss(
    from_logits: bool = True,
    reduction: str = tf.keras.losses.Reduction.SUM_OVER_BATCH_SIZE,
    name: str = 'sparsemax_loss'
)

Computes the generalized multi-label classification loss for the sparsemax function.

Because the sparsemax loss function needs both the probability output and the logits to compute the loss value, from_logits must be True.

Because it computes the generalized multi-label loss, the shape of both y_pred and y_true must be [batch_size, num_classes].

Args
from_logits	Whether y_pred is expected to be a logits tensor. Default is True, meaning y_pred is the logits.
reduction	(Optional) Type of tf.keras.losses.Reduction to apply to loss. Default value is SUM_OVER_BATCH_SIZE.
name	Optional name for the op.

Methods

from_config

@classmethod
from_config(
    config
)

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

Args
config	Output of get_config().

Returns
A Loss instance.

get_config

View source

get_config()

Returns the config dictionary for a Loss instance.

__call__

__call__(
    y_true, y_pred, sample_weight=None
)

Invokes the Loss instance.

Args
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.)

Returns
Weighted loss float Tensor. If reduction is NONE, this has shape [batch_size, d0, .. dN-1]; otherwise, it is scalar. (Note dN-1 because all loss functions reduce by 1 dimension, usually axis=-1.)

Raises
ValueError	If the shape of sample_weight is invalid.