oneflow.nn.MarginRankingLoss¶

class oneflow.nn.MarginRankingLoss(margin: float = 0.0, reduction: str = 'mean')¶

Creates a criterion that measures the loss given inputs \(x1\), \(x2\), two 1D mini-batch Tensors, and a label 1D mini-batch tensor \(y\) (containing 1 or -1).

If \(y = 1\) then it assumed the first input should be ranked higher (have a larger value) than the second input, and vice-versa for \(y = -1\).

The loss function for each sample in the mini-batch is:

\[\text{loss}(x1, x2, y) = \max(0, -y * (x1 - x2) + \text{margin})\]

Parameters

margin (float, optional) – Has a default value of \(0\).
reduction (string, optional) – Specifies the reduction to apply to the output: 'none' | 'mean' | 'sum'. 'none': no reduction will be applied, 'mean': the sum of the output will be divided by the number of elements in the output, 'sum': the output will be summed. Default: 'mean'

Shape:

x1 : \((N, D)\) where N is the batch size and D is the size of a sample.
x2 : \((N, D)\) where N is the batch size and D is the size of a sample.
Target: \((N)\)
Output: scalar. If reduction is 'none', then \((N)\).

For example:

>>> import oneflow as flow
>>> import numpy as np
>>> x1 = flow.tensor(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]), dtype=flow.float32)
>>> x2 = flow.tensor(np.array([[2, 2, 2], [2, 2, 2], [2, 2, 2]]), dtype=flow.float32)
>>> target = flow.tensor(np.array([[1, -1, 1],[-1, 1, -1], [1, 1, 1]]), dtype=flow.float32)
>>> m = flow.nn.MarginRankingLoss(margin =1.0, reduction="none")
>>> out = m(x1, x2, target)
>>> out
tensor([[2., 1., 0.],
        [3., 0., 5.],
        [0., 0., 0.]], dtype=oneflow.float32)

>>> m = flow.nn.MarginRankingLoss(margin = 0.3, reduction="sum")
>>> out = m(x1, x2, target)
>>> out
tensor(8.2000, dtype=oneflow.float32)

>>> m = flow.nn.MarginRankingLoss(margin = 10, reduction="mean")
>>> out = m(x1, x2, target)
>>> out
tensor(8.3333, dtype=oneflow.float32)

__init__(margin: float = 0.0, reduction: str = 'mean') → None ¶: Initialize self. See help(type(self)) for accurate signature.

Methods

`__call__`(args, *kwargs)	Call self as a function.
`__delattr__`(name, /)	Implement delattr(self, name).
`__dir__`()	Default dir() implementation.
`__eq__`(value, /)	Return self==value.
`__format__`(format_spec, /)	Default object formatter.
`__ge__`(value, /)	Return self>=value.
`__getattr__`(name)
`__getattribute__`(name, /)	Return getattr(self, name).
`__gt__`(value, /)	Return self>value.
`__hash__`()	Return hash(self).
`__init__`([margin, reduction])	Initialize self.
`__init_subclass__`	This method is called when a class is subclassed.
`__le__`(value, /)	Return self<=value.
`__lt__`(value, /)	Return self<value.
`__ne__`(value, /)	Return self!=value.
`__new__`(**kwargs)	Create and return a new object.
`__reduce__`()	Helper for pickle.
`__reduce_ex__`(protocol, /)	Helper for pickle.
`__repr__`()	Return repr(self).
`__setattr__`(name, value)	Implement setattr(self, name, value).
`__sizeof__`()	Size of object in memory, in bytes.
`__str__`()	Return str(self).
`__subclasshook__`	Abstract classes can override this to customize issubclass().
`_apply`(fn[, applied_dict])
`_get_name`()
`_load_from_state_dict`(state_dict, prefix, …)
`_named_members`(get_members_fn[, prefix, recurse])
`_save_to_state_dict`(destination, prefix, …)
`_shallow_repr`()
`add_module`(name, module)	Adds a child module to the current module.
`apply`(fn)	Applies `fn` recursively to every submodule (as returned by `.children()`) as well as self.
`buffers`([recurse])	Returns an iterator over module buffers.
`children`()	Returns an iterator over immediate children modules.
`cpu`()	Moves all model parameters and buffers to the CPU.
`cuda`([device])	Moves all model parameters and buffers to the GPU.
`double`()	Casts all floating point parameters and buffers to `double` datatype.
`eval`()	Sets the module in evaluation mode.
`extra_repr`()	Set the extra representation of the module
`float`()	Casts all floating point parameters and buffers to `float` datatype.
`forward`(input1, input2, target)
`half`()	Casts all floating point parameters and buffers to `half` datatype.
`load_state_dict`(state_dict[, strict])	Copies parameters and buffers from `state_dict` into this module and its descendants.
`modules`()	Returns an iterator over all modules in the network.
`named_buffers`([prefix, recurse])	Returns an iterator over module buffers, yielding both the name of the buffer as well as the buffer itself.
`named_children`()	Returns an iterator over immediate children modules, yielding both the name of the module as well as the module itself.
`named_modules`([memo, prefix])	Returns an iterator over all modules in the network, yielding both the name of the module as well as the module itself.
`named_parameters`([prefix, recurse])	Returns an iterator over module parameters, yielding both the name of the parameter as well as the parameter itself.
`parameters`([recurse])	Returns an iterator over module parameters.
`register_buffer`(name, tensor[, persistent])	Adds a buffer to the module.
`register_forward_hook`(hook)	Registers a forward hook on the module.
`register_forward_pre_hook`(hook)	Registers a forward pre-hook on the module.
`register_parameter`(name, param)	Adds a parameter to the module.
`state_dict`([destination, prefix, keep_vars])	Returns a dictionary containing a whole state of the module.
`to`([device])	Moves the parameters and buffers.
`to_consistent`(args, *kwargs)	This interface is no longer available, please use `oneflow.nn.Module.to_global()` instead.
`to_global`([placement, sbp])	Convert the parameters and buffers to global.
`train`([mode])	Sets the module in training mode.
`zero_grad`([set_to_none])	Sets gradients of all model parameters to zero.