import numbers
from typing import Callable, Tuple, Union
import torch
from ignite.exceptions import NotComputableError
from ignite.metrics.metric import Metric, reinit__is_reduced, sync_all_reduce
__all__ = ["VariableAccumulation", "GeometricAverage", "Average"]
[docs]class VariableAccumulation(Metric):
"""Single variable accumulator helper to compute (arithmetic, geometric, harmonic) average of a single variable.
- ``update`` must receive output of the form `x`.
- `x` can be a number or `torch.Tensor`.
Note:
The class stores input into two public variables: `accumulator` and `num_examples`.
Number of samples is updated following the rule:
- `+1` if input is a number
- `+1` if input is a 1D `torch.Tensor`
- `+batch_size` if input is a ND `torch.Tensor`. Batch size is the first dimension (`shape[0]`).
Args:
op: a callable to update accumulator. Method's signature is `(accumulator, output)`.
For example, to compute arithmetic mean value, `op = lambda a, x: a + x`.
output_transform: a callable that is used to transform the
:class:`~ignite.engine.engine.Engine`'s ``process_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.
device: specifies which device updates are accumulated on. Setting the metric's
device to be the same as your ``update`` arguments ensures the ``update`` method is non-blocking. By
default, CPU.
"""
required_output_keys = None
def __init__(
self,
op: Callable,
output_transform: Callable = lambda x: x,
device: Union[str, torch.device] = torch.device("cpu"),
):
if not callable(op):
raise TypeError(f"Argument op should be a callable, but given {type(op)}")
self._op = op
super(VariableAccumulation, self).__init__(output_transform=output_transform, device=device)
[docs] @reinit__is_reduced
def reset(self) -> None:
self.accumulator = torch.tensor(0.0, dtype=torch.float64, device=self._device)
self.num_examples = 0
def _check_output_type(self, output: Union[float, torch.Tensor]) -> None:
if not isinstance(output, (numbers.Number, torch.Tensor)):
raise TypeError(f"Output should be a number or torch.Tensor, but given {type(output)}")
[docs] @reinit__is_reduced
def update(self, output: Union[float, torch.Tensor]) -> None:
self._check_output_type(output)
if isinstance(output, torch.Tensor):
output = output.detach()
if not (output.device == self._device and output.dtype == self.accumulator.dtype):
output = output.to(self.accumulator)
self.accumulator = self._op(self.accumulator, output)
if isinstance(output, torch.Tensor):
self.num_examples += output.shape[0] if len(output.shape) > 1 else 1
else:
self.num_examples += 1
[docs] @sync_all_reduce("accumulator", "num_examples")
def compute(self) -> Tuple[torch.Tensor, int]:
return self.accumulator, self.num_examples
[docs]class Average(VariableAccumulation):
"""Helper class to compute arithmetic average of a single variable.
- ``update`` must receive output of the form `x`.
- `x` can be a number or `torch.Tensor`.
Note:
Number of samples is updated following the rule:
- `+1` if input is a number
- `+1` if input is a 1D `torch.Tensor`
- `+batch_size` if input is an ND `torch.Tensor`. Batch size is the first dimension (`shape[0]`).
For input `x` being an ND `torch.Tensor` with N > 1, the first dimension is seen as the number of samples and
is summed up and added to the accumulator: `accumulator += x.sum(dim=0)`
``output_tranform`` can be added to the metric to transform the output into the form expected by the metric.
Args:
output_transform: a callable that is used to transform the
:class:`~ignite.engine.engine.Engine`'s ``process_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.
device: specifies which device updates are accumulated on. Setting the metric's
device to be the same as your ``update`` arguments ensures the ``update`` method is non-blocking. By
default, CPU.
Examples:
.. testcode::
metric = Average()
metric.attach(default_evaluator, 'avg')
# Case 1. input is er
data = torch.Tensor([0, 1, 2, 3, 4])
state = default_evaluator.run(data)
print(state.metrics['avg'])
.. testoutput::
2.0
.. testcode::
metric = Average()
metric.attach(default_evaluator, 'avg')
# Case 2. input is a 1D torch.Tensor
data = torch.Tensor([
[0, 0, 0],
[1, 1, 1],
[2, 2, 2],
[3, 3, 3]
])
state = default_evaluator.run(data)
print(state.metrics['avg'])
.. testoutput::
tensor([1.5000, 1.5000, 1.5000], dtype=torch.float64)
.. testcode::
metric = Average()
metric.attach(default_evaluator, 'avg')
# Case 3. input is a ND torch.Tensor
data = [
torch.Tensor([[0, 0, 0], [1, 1, 1]]),
torch.Tensor([[2, 2, 2], [3, 3, 3]])
]
state = default_evaluator.run(data)
print(state.metrics['avg'])
.. testoutput::
tensor([1.5000, 1.5000, 1.5000], dtype=torch.float64)
"""
def __init__(
self, output_transform: Callable = lambda x: x, device: Union[str, torch.device] = torch.device("cpu")
):
def _mean_op(a: Union[float, torch.Tensor], x: Union[float, torch.Tensor]) -> Union[float, torch.Tensor]:
if isinstance(x, torch.Tensor) and x.ndim > 1:
x = x.sum(dim=0)
return a + x
super(Average, self).__init__(op=_mean_op, output_transform=output_transform, device=device)
[docs] @sync_all_reduce("accumulator", "num_examples")
def compute(self) -> Union[float, torch.Tensor]:
if self.num_examples < 1:
raise NotComputableError(
f"{self.__class__.__name__} must have at least one example before it can be computed."
)
return self.accumulator / self.num_examples
[docs]class GeometricAverage(VariableAccumulation):
"""Helper class to compute geometric average of a single variable.
- ``update`` must receive output of the form `x`.
- `x` can be a positive number or a positive `torch.Tensor`, such that ``torch.log(x)`` is not `nan`.
Args:
output_transform: a callable that is used to transform the
:class:`~ignite.engine.engine.Engine`'s ``process_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.
device: specifies which device updates are accumulated on. Setting the metric's
device to be the same as your ``update`` arguments ensures the ``update`` method is non-blocking. By
default, CPU.
Note:
Number of samples is updated following the rule:
- `+1` if input is a number
- `+1` if input is a 1D `torch.Tensor`
- `+batch_size` if input is a ND `torch.Tensor`. Batch size is the first dimension (`shape[0]`).
For input `x` being an ND `torch.Tensor` with N > 1, the first dimension is seen as the number of samples and
is aggregated and added to the accumulator: `accumulator *= prod(x, dim=0)`
``output_tranform`` can be added to the metric to transform the output into the form expected by the metric.
Examples:
.. testcode::
metric = GeometricAverage()
metric.attach(default_evaluator, 'avg')
# Case 1. input is er
data = torch.Tensor([1, 2, 3])
state = default_evaluator.run(data)
print(state.metrics['avg'])
.. testoutput::
1.8171...
.. testcode::
metric = GeometricAverage()
metric.attach(default_evaluator, 'avg')
# Case 2. input is a 1D torch.Tensor
data = torch.Tensor([
[1, 1, 1],
[2, 2, 2],
[3, 3, 3],
[4, 4, 4],
])
state = default_evaluator.run(data)
print(state.metrics['avg'])
.. testoutput::
tensor([2.2134, 2.2134, 2.2134], dtype=torch.float64)
.. testcode::
metric = GeometricAverage()
metric.attach(default_evaluator, 'avg')
# Case 3. input is a ND torch.Tensor
data = [
torch.Tensor([[1, 1, 1], [2, 2, 2]]),
torch.Tensor([[3, 3, 3], [4, 4, 4]])
]
state = default_evaluator.run(data)
print(state.metrics['avg'])
.. testoutput::
tensor([2.2134, 2.2134, 2.2134], dtype=torch.float64)
"""
def __init__(
self, output_transform: Callable = lambda x: x, device: Union[str, torch.device] = torch.device("cpu")
):
def _geom_op(a: torch.Tensor, x: Union[float, torch.Tensor]) -> torch.Tensor:
if not isinstance(x, torch.Tensor):
x = torch.tensor(x)
x = torch.log(x)
if x.ndim > 1:
x = x.sum(dim=0)
return a + x
super(GeometricAverage, self).__init__(op=_geom_op, output_transform=output_transform, device=device)
[docs] @sync_all_reduce("accumulator", "num_examples")
def compute(self) -> Union[float, torch.Tensor]:
if self.num_examples < 1:
raise NotComputableError(
f"{self.__class__.__name__} must have at least one example before it can be computed."
)
tensor = torch.exp(self.accumulator / self.num_examples)
if tensor.numel() == 1:
return tensor.item()
return tensor