Probabilistic losses
- Original Link : https://keras.io/api/losses/probabilistic_losses/
- Last Checked at : 2024-11-25
BinaryCrossentropy
class
keras.losses.BinaryCrossentropy(
from_logits=False,
label_smoothing=0.0,
axis=-1,
reduction="sum_over_batch_size",
name="binary_crossentropy",
dtype=None,
)
Computes the cross-entropy loss between true labels and predicted labels.
Use this cross-entropy loss for binary (0 or 1) classification applications. The loss function requires the following inputs:
y_true
(true label): This is either 0 or 1.y_pred
(predicted value): This is the model’s prediction, i.e, a single floating-point value which either represents a logit, (i.e, value in [-inf, inf] whenfrom_logits=True
) or a probability (i.e, value in [0., 1.] whenfrom_logits=False
).
Arguments
- from_logits: Whether to interpret
y_pred
as a tensor of logit values. By default, we assume thaty_pred
is probabilities (i.e., values in [0, 1]). - label_smoothing: Float in range [0, 1]. When 0, no smoothing occurs.
When > 0, we compute the loss between the predicted labels
and a smoothed version of the true labels, where the smoothing
squeezes the labels towards 0.5. Larger values of
label_smoothing
correspond to heavier smoothing. - axis: The axis along which to compute crossentropy (the features axis).
Defaults to
-1
. - reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
Examples
Recommended Usage: (set from_logits=True
)
With compile()
API:
model.compile(
loss=keras.losses.BinaryCrossentropy(from_logits=True),
...
)
As a standalone function:
>>> # Example 1: (batch_size = 1, number of samples = 4)
>>> y_true = np.array([0, 1, 0, 0])
>>> y_pred = np.array([-18.6, 0.51, 2.94, -12.8])
>>> bce = keras.losses.BinaryCrossentropy(from_logits=True)
>>> bce(y_true, y_pred)
0.8654
>>> # Example 2: (batch_size = 2, number of samples = 4)
>>> y_true = np.array([[0, 1], [0, 0]])
>>> y_pred = np.array([[-18.6, 0.51], [2.94, -12.8]])
>>> # Using default 'auto'/'sum_over_batch_size' reduction type.
>>> bce = keras.losses.BinaryCrossentropy(from_logits=True)
>>> bce(y_true, y_pred)
0.8654
>>> # Using 'sample_weight' attribute
>>> bce(y_true, y_pred, sample_weight=[0.8, 0.2])
0.243
>>> # Using 'sum' reduction` type.
>>> bce = keras.losses.BinaryCrossentropy(from_logits=True,
... reduction="sum")
>>> bce(y_true, y_pred)
1.730
>>> # Using 'none' reduction type.
>>> bce = keras.losses.BinaryCrossentropy(from_logits=True,
... reduction=None)
>>> bce(y_true, y_pred)
array([0.235, 1.496], dtype=float32)
Default Usage: (set from_logits=False
)
>>> # Make the following updates to the above "Recommended Usage" section
>>> # 1. Set `from_logits=False`
>>> keras.losses.BinaryCrossentropy() # OR ...('from_logits=False')
>>> # 2. Update `y_pred` to use probabilities instead of logits
>>> y_pred = [0.6, 0.3, 0.2, 0.8] # OR [[0.6, 0.3], [0.2, 0.8]]
BinaryFocalCrossentropy
class
keras.losses.BinaryFocalCrossentropy(
apply_class_balancing=False,
alpha=0.25,
gamma=2.0,
from_logits=False,
label_smoothing=0.0,
axis=-1,
reduction="sum_over_batch_size",
name="binary_focal_crossentropy",
dtype=None,
)
Computes focal cross-entropy loss between true labels and predictions.
Binary cross-entropy loss is often used for binary (0 or 1) classification tasks. The loss function requires the following inputs:
y_true
(true label): This is either 0 or 1.y_pred
(predicted value): This is the model’s prediction, i.e, a single floating-point value which either represents a logit, (i.e, value in [-inf, inf] whenfrom_logits=True
) or a probability (i.e, value in[0., 1.]
whenfrom_logits=False
).
According to Lin et al., 2018, it helps to apply a “focal factor” to down-weight easy examples and focus more on hard examples. By default, the focal tensor is computed as follows:
focal_factor = (1 - output) ** gamma
for class 1
focal_factor = output ** gamma
for class 0
where gamma
is a focusing parameter. When gamma=0
, this function is
equivalent to the binary crossentropy loss.
Arguments
- apply_class_balancing: A bool, whether to apply weight balancing on the binary classes 0 and 1.
- alpha: A weight balancing factor for class 1, default is
0.25
as mentioned in reference Lin et al., 2018. The weight for class 0 is1.0 - alpha
. - gamma: A focusing parameter used to compute the focal factor, default is
2.0
as mentioned in the reference Lin et al., 2018. - from_logits: Whether to interpret
y_pred
as a tensor of logit values. By default, we assume thaty_pred
are probabilities (i.e., values in[0, 1]
). - label_smoothing: Float in
[0, 1]
. When0
, no smoothing occurs. When >0
, we compute the loss between the predicted labels and a smoothed version of the true labels, where the smoothing squeezes the labels towards0.5
. Larger values oflabel_smoothing
correspond to heavier smoothing. - axis: The axis along which to compute crossentropy (the features axis).
Defaults to
-1
. - reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
Examples
With the compile()
API:
model.compile(
loss=keras.losses.BinaryFocalCrossentropy(
gamma=2.0, from_logits=True),
...
)
As a standalone function:
>>> # Example 1: (batch_size = 1, number of samples = 4)
>>> y_true = [0, 1, 0, 0]
>>> y_pred = [-18.6, 0.51, 2.94, -12.8]
>>> loss = keras.losses.BinaryFocalCrossentropy(
... gamma=2, from_logits=True)
>>> loss(y_true, y_pred)
0.691
>>> # Apply class weight
>>> loss = keras.losses.BinaryFocalCrossentropy(
... apply_class_balancing=True, gamma=2, from_logits=True)
>>> loss(y_true, y_pred)
0.51
>>> # Example 2: (batch_size = 2, number of samples = 4)
>>> y_true = [[0, 1], [0, 0]]
>>> y_pred = [[-18.6, 0.51], [2.94, -12.8]]
>>> # Using default 'auto'/'sum_over_batch_size' reduction type.
>>> loss = keras.losses.BinaryFocalCrossentropy(
... gamma=3, from_logits=True)
>>> loss(y_true, y_pred)
0.647
>>> # Apply class weight
>>> loss = keras.losses.BinaryFocalCrossentropy(
... apply_class_balancing=True, gamma=3, from_logits=True)
>>> loss(y_true, y_pred)
0.482
>>> # Using 'sample_weight' attribute with focal effect
>>> loss = keras.losses.BinaryFocalCrossentropy(
... gamma=3, from_logits=True)
>>> loss(y_true, y_pred, sample_weight=[0.8, 0.2])
0.133
>>> # Apply class weight
>>> loss = keras.losses.BinaryFocalCrossentropy(
... apply_class_balancing=True, gamma=3, from_logits=True)
>>> loss(y_true, y_pred, sample_weight=[0.8, 0.2])
0.097
>>> # Using 'sum' reduction` type.
>>> loss = keras.losses.BinaryFocalCrossentropy(
... gamma=4, from_logits=True,
... reduction="sum")
>>> loss(y_true, y_pred)
1.222
>>> # Apply class weight
>>> loss = keras.losses.BinaryFocalCrossentropy(
... apply_class_balancing=True, gamma=4, from_logits=True,
... reduction="sum")
>>> loss(y_true, y_pred)
0.914
>>> # Using 'none' reduction type.
>>> loss = keras.losses.BinaryFocalCrossentropy(
... gamma=5, from_logits=True,
... reduction=None)
>>> loss(y_true, y_pred)
array([0.0017 1.1561], dtype=float32)
>>> # Apply class weight
>>> loss = keras.losses.BinaryFocalCrossentropy(
... apply_class_balancing=True, gamma=5, from_logits=True,
... reduction=None)
>>> loss(y_true, y_pred)
array([0.0004 0.8670], dtype=float32)
CategoricalCrossentropy
class
keras.losses.CategoricalCrossentropy(
from_logits=False,
label_smoothing=0.0,
axis=-1,
reduction="sum_over_batch_size",
name="categorical_crossentropy",
dtype=None,
)
Computes the crossentropy loss between the labels and predictions.
Use this crossentropy loss function when there are two or more label
classes. We expect labels to be provided in a one_hot
representation. If
you want to provide labels as integers, please use
SparseCategoricalCrossentropy
loss. There should be num_classes
floating
point values per feature, i.e., the shape of both y_pred
and y_true
are
[batch_size, num_classes]
.
Arguments
- from_logits: Whether
y_pred
is expected to be a logits tensor. By default, we assume thaty_pred
encodes a probability distribution. - label_smoothing: Float in [0, 1]. When > 0, label values are smoothed,
meaning the confidence on label values are relaxed. For example, if
0.1
, use0.1 / num_classes
for non-target labels and0.9 + 0.1 / num_classes
for target labels. - axis: The axis along which to compute crossentropy (the features
axis). Defaults to
-1
. - reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
Examples
Standalone usage:
>>> y_true = [[0, 1, 0], [0, 0, 1]]
>>> y_pred = [[0.05, 0.95, 0], [0.1, 0.8, 0.1]]
>>> # Using 'auto'/'sum_over_batch_size' reduction type.
>>> cce = keras.losses.CategoricalCrossentropy()
>>> cce(y_true, y_pred)
1.177
>>> # Calling with 'sample_weight'.
>>> cce(y_true, y_pred, sample_weight=np.array([0.3, 0.7]))
0.814
>>> # Using 'sum' reduction type.
>>> cce = keras.losses.CategoricalCrossentropy(
... reduction="sum")
>>> cce(y_true, y_pred)
2.354
>>> # Using 'none' reduction type.
>>> cce = keras.losses.CategoricalCrossentropy(
... reduction=None)
>>> cce(y_true, y_pred)
array([0.0513, 2.303], dtype=float32)
Usage with the compile()
API:
model.compile(optimizer='sgd',
loss=keras.losses.CategoricalCrossentropy())
CategoricalFocalCrossentropy
class
keras.losses.CategoricalFocalCrossentropy(
alpha=0.25,
gamma=2.0,
from_logits=False,
label_smoothing=0.0,
axis=-1,
reduction="sum_over_batch_size",
name="categorical_focal_crossentropy",
dtype=None,
)
Computes the alpha balanced focal crossentropy loss.
Use this crossentropy loss function when there are two or more label
classes and if you want to handle class imbalance without using
class_weights
. We expect labels to be provided in a one_hot
representation.
According to Lin et al., 2018, it helps to apply a focal factor to down-weight easy examples and focus more on hard examples. The general formula for the focal loss (FL) is as follows:
FL(p_t) = (1 - p_t) ** gamma * log(p_t)
where p_t
is defined as follows:
p_t = output if y_true == 1, else 1 - output
(1 - p_t) ** gamma
is the modulating_factor
, where gamma
is a focusing
parameter. When gamma
= 0, there is no focal effect on the cross entropy.
gamma
reduces the importance given to simple examples in a smooth manner.
The authors use alpha-balanced variant of focal loss (FL) in the paper:
FL(p_t) = -alpha * (1 - p_t) ** gamma * log(p_t)
where alpha
is the weight factor for the classes. If alpha
= 1, the
loss won’t be able to handle class imbalance properly as all
classes will have the same weight. This can be a constant or a list of
constants. If alpha is a list, it must have the same length as the number
of classes.
The formula above can be generalized to:
FL(p_t) = alpha * (1 - p_t) ** gamma * CrossEntropy(y_true, y_pred)
where minus comes from CrossEntropy(y_true, y_pred)
(CE).
Extending this to multi-class case is straightforward:
FL(p_t) = alpha * (1 - p_t) ** gamma * CategoricalCE(y_true, y_pred)
In the snippet below, there is num_classes
floating pointing values per
example. The shape of both y_pred
and y_true
are
(batch_size, num_classes)
.
Arguments
- alpha: A weight balancing factor for all classes, default is
0.25
as mentioned in the reference. It can be a list of floats or a scalar. In the multi-class case, alpha may be set by inverse class frequency by usingcompute_class_weight
fromsklearn.utils
. - gamma: A focusing parameter, default is
2.0
as mentioned in the reference. It helps to gradually reduce the importance given to simple (easy) examples in a smooth manner. - from_logits: Whether
output
is expected to be a logits tensor. By default, we consider thatoutput
encodes a probability distribution. - label_smoothing: Float in [0, 1]. When > 0, label values are smoothed,
meaning the confidence on label values are relaxed. For example, if
0.1
, use0.1 / num_classes
for non-target labels and0.9 + 0.1 / num_classes
for target labels. - axis: The axis along which to compute crossentropy (the features
axis). Defaults to
-1
. - reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
Examples
Standalone usage:
>>> y_true = [[0., 1., 0.], [0., 0., 1.]]
>>> y_pred = [[0.05, 0.95, 0], [0.1, 0.8, 0.1]]
>>> # Using 'auto'/'sum_over_batch_size' reduction type.
>>> cce = keras.losses.CategoricalFocalCrossentropy()
>>> cce(y_true, y_pred)
0.23315276
>>> # Calling with 'sample_weight'.
>>> cce(y_true, y_pred, sample_weight=np.array([0.3, 0.7]))
0.1632
>>> # Using 'sum' reduction type.
>>> cce = keras.losses.CategoricalFocalCrossentropy(
... reduction="sum")
>>> cce(y_true, y_pred)
0.46631
>>> # Using 'none' reduction type.
>>> cce = keras.losses.CategoricalFocalCrossentropy(
... reduction=None)
>>> cce(y_true, y_pred)
array([3.2058331e-05, 4.6627346e-01], dtype=float32)
Usage with the compile()
API:
model.compile(optimizer='adam',
loss=keras.losses.CategoricalFocalCrossentropy())
SparseCategoricalCrossentropy
class
keras.losses.SparseCategoricalCrossentropy(
from_logits=False,
ignore_class=None,
reduction="sum_over_batch_size",
name="sparse_categorical_crossentropy",
dtype=None,
)
Computes the crossentropy loss between the labels and predictions.
Use this crossentropy loss function when there are two or more label
classes. We expect labels to be provided as integers. If you want to
provide labels using one-hot
representation, please use
CategoricalCrossentropy
loss. There should be # classes
floating point
values per feature for y_pred
and a single floating point value per
feature for y_true
.
In the snippet below, there is a single floating point value per example for
y_true
and num_classes
floating pointing values per example for
y_pred
. The shape of y_true
is [batch_size]
and the shape of y_pred
is [batch_size, num_classes]
.
Arguments
- from_logits: Whether
y_pred
is expected to be a logits tensor. By default, we assume thaty_pred
encodes a probability distribution. - reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
Examples
>>> y_true = [1, 2]
>>> y_pred = [[0.05, 0.95, 0], [0.1, 0.8, 0.1]]
>>> # Using 'auto'/'sum_over_batch_size' reduction type.
>>> scce = keras.losses.SparseCategoricalCrossentropy()
>>> scce(y_true, y_pred)
1.177
>>> # Calling with 'sample_weight'.
>>> scce(y_true, y_pred, sample_weight=np.array([0.3, 0.7]))
0.814
>>> # Using 'sum' reduction type.
>>> scce = keras.losses.SparseCategoricalCrossentropy(
... reduction="sum")
>>> scce(y_true, y_pred)
2.354
>>> # Using 'none' reduction type.
>>> scce = keras.losses.SparseCategoricalCrossentropy(
... reduction=None)
>>> scce(y_true, y_pred)
array([0.0513, 2.303], dtype=float32)
Usage with the compile()
API:
model.compile(optimizer='sgd',
loss=keras.losses.SparseCategoricalCrossentropy())
Poisson
class
keras.losses.Poisson(reduction="sum_over_batch_size", name="poisson", dtype=None)
Computes the Poisson loss between y_true
& y_pred
.
Formula:
loss = y_pred - y_true * log(y_pred)
Arguments
- reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
CTC
class
keras.losses.CTC(reduction="sum_over_batch_size", name="ctc", dtype=None)
CTC (Connectionist Temporal Classification) loss.
Arguments
- reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
KLDivergence
class
keras.losses.KLDivergence(
reduction="sum_over_batch_size", name="kl_divergence", dtype=None
)
Computes Kullback-Leibler divergence loss between y_true
& y_pred
.
Formula:
loss = y_true * log(y_true / y_pred)
y_true
and y_pred
are expected to be probability
distributions, with values between 0 and 1. They will get
clipped to the [0, 1]
range.
Arguments
- reduction: Type of reduction to apply to the loss. In almost all cases
this should be
"sum_over_batch_size"
. Supported options are"sum"
,"sum_over_batch_size"
orNone
. - name: Optional name for the loss instance.
- dtype: The dtype of the loss’s computations. Defaults to
None
, which means usingkeras.backend.floatx()
.keras.backend.floatx()
is a"float32"
unless set to different value (viakeras.backend.set_floatx()
). If akeras.DTypePolicy
is provided, then thecompute_dtype
will be utilized.
binary_crossentropy
function
keras.losses.binary_crossentropy(
y_true, y_pred, from_logits=False, label_smoothing=0.0, axis=-1
)
Computes the binary crossentropy loss.
Arguments
- y_true: Ground truth values. shape =
[batch_size, d0, .. dN]
. - y_pred: The predicted values. shape =
[batch_size, d0, .. dN]
. - from_logits: Whether
y_pred
is expected to be a logits tensor. By default, we assume thaty_pred
encodes a probability distribution. - label_smoothing: Float in
[0, 1]
. If >0
then smooth the labels by squeezing them towards 0.5, that is, using1. - 0.5 * label_smoothing
for the target class and0.5 * label_smoothing
for the non-target class. - axis: The axis along which the mean is computed. Defaults to
-1
.
Returns
Binary crossentropy loss value. shape = [batch_size, d0, .. dN-1]
.
Example
>>> y_true = [[0, 1], [0, 0]]
>>> y_pred = [[0.6, 0.4], [0.4, 0.6]]
>>> loss = keras.losses.binary_crossentropy(y_true, y_pred)
>>> assert loss.shape == (2,)
>>> loss
array([0.916 , 0.714], dtype=float32)
categorical_crossentropy
function
keras.losses.categorical_crossentropy(
y_true, y_pred, from_logits=False, label_smoothing=0.0, axis=-1
)
Computes the categorical crossentropy loss.
Arguments
- y_true: Tensor of one-hot true targets.
- y_pred: Tensor of predicted targets.
- from_logits: Whether
y_pred
is expected to be a logits tensor. By default, we assume thaty_pred
encodes a probability distribution. - label_smoothing: Float in [0, 1]. If >
0
then smooth the labels. For example, if0.1
, use0.1 / num_classes
for non-target labels and0.9 + 0.1 / num_classes
for target labels. - axis: Defaults to
-1
. The dimension along which the entropy is computed.
Returns
Categorical crossentropy loss value.
Example
>>> y_true = [[0, 1, 0], [0, 0, 1]]
>>> y_pred = [[0.05, 0.95, 0], [0.1, 0.8, 0.1]]
>>> loss = keras.losses.categorical_crossentropy(y_true, y_pred)
>>> assert loss.shape == (2,)
>>> loss
array([0.0513, 2.303], dtype=float32)
sparse_categorical_crossentropy
function
keras.losses.sparse_categorical_crossentropy(
y_true, y_pred, from_logits=False, ignore_class=None, axis=-1
)
Computes the sparse categorical crossentropy loss.
Arguments
- y_true: Ground truth values.
- y_pred: The predicted values.
- from_logits: Whether
y_pred
is expected to be a logits tensor. By default, we assume thaty_pred
encodes a probability distribution. - ignore_class: Optional integer. The ID of a class to be ignored during
loss computation. This is useful, for example, in segmentation
problems featuring a “void” class (commonly -1 or 255) in
segmentation maps. By default (
ignore_class=None
), all classes are considered. - axis: Defaults to
-1
. The dimension along which the entropy is computed.
Returns
Sparse categorical crossentropy loss value.
Examples
>>> y_true = [1, 2]
>>> y_pred = [[0.05, 0.95, 0], [0.1, 0.8, 0.1]]
>>> loss = keras.losses.sparse_categorical_crossentropy(y_true, y_pred)
>>> assert loss.shape == (2,)
>>> loss
array([0.0513, 2.303], dtype=float32)
poisson
function
keras.losses.poisson(y_true, y_pred)
Computes the Poisson loss between y_true and y_pred.
Formula:
loss = y_pred - y_true * log(y_pred)
Arguments
- y_true: Ground truth values. shape =
[batch_size, d0, .. dN]
. - y_pred: The predicted values. shape =
[batch_size, d0, .. dN]
.
Returns
Poisson loss values with shape = [batch_size, d0, .. dN-1]
.
Example
>>> y_true = np.random.randint(0, 2, size=(2, 3))
>>> y_pred = np.random.random(size=(2, 3))
>>> loss = keras.losses.poisson(y_true, y_pred)
>>> assert loss.shape == (2,)
>>> y_pred = y_pred + 1e-7
>>> assert np.allclose(
... loss, np.mean(y_pred - y_true * np.log(y_pred), axis=-1),
... atol=1e-5)
ctc
function
keras.losses.ctc(y_true, y_pred)
CTC (Connectionist Temporal Classification) loss.
Arguments
- y_true: A tensor of shape
(batch_size, max_length)
containing the true labels in integer format.0
always represents the blank/mask index and should not be used for classes. - y_pred: A tensor of shape
(batch_size, max_length, num_classes)
containing logits (the output of your model). They should not be normalized via softmax.
kl_divergence
function
keras.losses.kl_divergence(y_true, y_pred)
Computes Kullback-Leibler divergence loss between y_true
& y_pred
.
Formula:
loss = y_true * log(y_true / y_pred)
y_true
and y_pred
are expected to be probability
distributions, with values between 0 and 1. They will get
clipped to the [0, 1]
range.
Arguments
- y_true: Tensor of true targets.
- y_pred: Tensor of predicted targets.
Returns
KL Divergence loss values with shape = [batch_size, d0, .. dN-1]
.
Example
>>> y_true = np.random.randint(0, 2, size=(2, 3)).astype(np.float32)
>>> y_pred = np.random.random(size=(2, 3))
>>> loss = keras.losses.kl_divergence(y_true, y_pred)
>>> assert loss.shape == (2,)
>>> y_true = ops.clip(y_true, 1e-7, 1)
>>> y_pred = ops.clip(y_pred, 1e-7, 1)
>>> assert np.array_equal(
... loss, np.sum(y_true * np.log(y_true / y_pred), axis=-1))