HSIC#
- class ignite.metrics.HSIC(sigma_x=-1, sigma_y=-1, ignore_invalid_batch=True, output_transform=<function HSIC.<lambda>>, device=device(type='cpu'), skip_unrolling=False)[source]#
Calculates the Hilbert-Schmidt Independence Criterion (HSIC).
where is the batch size, and and are the Gram matrices of the Gaussian RBF kernel with their diagonal entries being set to zero.
HSIC measures non-linear statistical independence between features and . HSIC becomes zero if and only if and are independent.
This metric computes the unbiased estimator of HSIC proposed in Song et al. (2012). The HSIC is estimated using Eq. (5) of the paper for each batch and the average is accumulated.
Each batch must contain at least four samples.
update
must receive output of the form(y_pred, y)
.
- Parameters
sigma_x (float) – bandwidth of the kernel for . If negative, a heuristic value determined by the median of the distances between the samples is used. Default: -1
sigma_y (float) – bandwidth of the kernel for . If negative, a heuristic value determined by the median of the distances between the samples is used. Default: -1
ignore_invalid_batch (bool) – If
True
, computation for a batch with less than four samples is skipped. IfFalse
,ValueError
is raised when received such a batch.output_transform (Callable) – a callable that is used to transform the
Engine
’sprocess_function
’s output into the form expected by the metric. This can be useful if, for example, you have a multi-output model and you want to compute the metric with respect to one of the outputs. By default, metrics require the output as(y_pred, y)
or{'y_pred': y_pred, 'y': y}
.device (Union[str, device]) – specifies which device updates are accumulated on. Setting the metric’s device to be the same as your
update
arguments ensures theupdate
method is non-blocking. By default, CPU.skip_unrolling (bool) – specifies whether output should be unrolled before being fed to update method. Should be true for multi-output model, for example, if
y_pred
contains multi-ouput as(y_pred_a, y_pred_b)
Alternatively,output_transform
can be used to handle this.
Examples
To use with
Engine
andprocess_function
, simply attach the metric instance to the engine. The output of the engine’sprocess_function
needs to be in the format of(y_pred, y)
or{'y_pred': y_pred, 'y': y, ...}
. If not,output_tranform
can be added to the metric to transform the output into the form expected by the metric.y_pred
andy
should have the same shape.For more information on how metric works with
Engine
, visit Attach Engine API.from collections import OrderedDict import torch from torch import nn, optim from ignite.engine import * from ignite.handlers import * from ignite.metrics import * from ignite.metrics.clustering import * from ignite.metrics.regression import * from ignite.utils import * # create default evaluator for doctests def eval_step(engine, batch): return batch default_evaluator = Engine(eval_step) # create default optimizer for doctests param_tensor = torch.zeros([1], requires_grad=True) default_optimizer = torch.optim.SGD([param_tensor], lr=0.1) # create default trainer for doctests # as handlers could be attached to the trainer, # each test must define his own trainer using `.. testsetup:` def get_default_trainer(): def train_step(engine, batch): return batch return Engine(train_step) # create default model for doctests default_model = nn.Sequential(OrderedDict([ ('base', nn.Linear(4, 2)), ('fc', nn.Linear(2, 1)) ])) manual_seed(666)
metric = HSIC() metric.attach(default_evaluator, "hsic") X = torch.tensor([[0., 1., 2., 3., 4.], [5., 6., 7., 8., 9.], [10., 11., 12., 13., 14.], [15., 16., 17., 18., 19.], [20., 21., 22., 23., 24.], [25., 26., 27., 28., 29.], [30., 31., 32., 33., 34.], [35., 36., 37., 38., 39.], [40., 41., 42., 43., 44.], [45., 46., 47., 48., 49.]]) Y = torch.sin(X * torch.pi * 2 / 50) state = default_evaluator.run([[X, Y]]) print(state.metrics["hsic"])
0.09226646274328232
New in version 0.5.2.
Methods
Computes the metric based on its accumulated state.
Resets the metric to its initial state.
Updates the metric's state using the passed batch output.
- compute()[source]#
Computes the metric based on its accumulated state.
By default, this is called at the end of each epoch.
- Returns
- the actual quantity of interest. However, if a
Mapping
is returned, it will be (shallow) flattened into engine.state.metrics whencompleted()
is called. - Return type
Any
- Raises
NotComputableError – raised when the metric cannot be computed.