versions/1.0.0/_sources/api/python/symbol.txt - mxnet-site - Git at Google

 # Symbol API

 ```eval_rst
     .. currentmodule:: mxnet.symbol
 ```

 ## Overview

 This document lists the routines of the symbolic expression package:

 ```eval_rst
 .. autosummary::
     :nosignatures:

     mxnet.symbol
 ```

 The `Symbol` API, defined in the `symbol` (or simply `sym`) package, provides
 neural network graphs and auto-differentiation.
 A symbol represents a multi-output symbolic expression.
 They are composited by operators, such as simple matrix operations (e.g. “+”),
 or a neural network layer (e.g. convolution layer).
 An operator can take several input variables,
 produce more than one output variables, and have internal state variables.
 A variable can be either free, which we can bind with value later,
 or an output of another symbol.

 ```python
 >>> a = mx.sym.Variable('a')
 >>> b = mx.sym.Variable('b')
 >>> c = 2 * a + b
 >>> type(c)
 <class 'mxnet.symbol.Symbol'>
 >>> e = c.bind(mx.cpu(), {'a': mx.nd.array([1,2]), 'b':mx.nd.array([2,3])})
 >>> y = e.forward()
 >>> y
 [<NDArray 2 @cpu(0)>]
 >>> y[0].asnumpy()
 array([ 4.,  7.], dtype=float32)
 ```

 A detailed tutorial is available at [Symbol - Neural network graphs and auto-differentiation](http://mxnet.io/tutorials/basic/symbol.html).
 <br><br>

 ```eval_rst

 .. note:: most operators provided in ``symbol`` are similar to those in ``ndarray``
    although there are few differences:

    - ``symbol`` adopts declarative programming. In other words, we need to first
      compose the computations, and then feed it with data for execution whereas
      ndarray adopts imperative programming.

    - Most binary operators in ``symbol`` such as ``+`` and ``>`` don't broadcast.
      We need to call the broadcast version of the operator such as ``broadcast_plus``
      explicitly.
 ```

 In the rest of this document, we first overview the methods provided by the
 `symbol.Symbol` class, and then list other routines provided by the
 `symbol` package.

 ## The `Symbol` class

 ### Composition

 Composite multiple symbols into a new one by an operator.

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.__call__
 ```

 #### Arithmetic operations

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.__add__
     Symbol.__sub__
     Symbol.__rsub__
     Symbol.__neg__
     Symbol.__mul__
     Symbol.__div__
     Symbol.__rdiv__
     Symbol.__mod__
     Symbol.__rmod__
     Symbol.__pow__
 ```

 #### Comparison operators

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.__lt__
     Symbol.__le__
     Symbol.__gt__
     Symbol.__ge__
     Symbol.__eq__
     Symbol.__ne__
 ```

 ### Symbol creation

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.zeros_like
     Symbol.ones_like
 ```

 ### Changing shape and type

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.astype
     Symbol.reshape
     Symbol.flatten
     Symbol.expand_dims
 ```

 ### Expanding elements

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.broadcast_to
     Symbol.broadcast_axes
     Symbol.tile
     Symbol.pad
 ```

 ### Rearranging elements

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.transpose
     Symbol.swapaxes
     Symbol.flip
 ```

 ### Reduce functions

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.sum
     Symbol.nansum
     Symbol.prod
     Symbol.nanprod
     Symbol.mean
     Symbol.max
     Symbol.min
     Symbol.norm
 ```

 ### Rounding

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.round
     Symbol.rint
     Symbol.fix
     Symbol.floor
     Symbol.ceil
     Symbol.trunc
 ```

 ### Sorting and searching

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.sort
     Symbol.argsort
     Symbol.topk
     Symbol.argmax
     Symbol.argmin
 ```

 ### Query information

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.name
     Symbol.list_arguments
     Symbol.list_outputs
     Symbol.list_auxiliary_states
     Symbol.list_attr
     Symbol.attr
     Symbol.attr_dict
 ```

 ### Indexing

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.slice
     Symbol.slice_axis
     Symbol.take
     Symbol.one_hot
     Symbol.pick
 ```

 ### Get internal and output symbol

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.__getitem__
     Symbol.__iter__
     Symbol.get_internals
     Symbol.get_children
 ```

 ### Inference type and shape

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.infer_type
     Symbol.infer_shape
     Symbol.infer_shape_partial
 ```


 ### Bind

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.bind
     Symbol.simple_bind
 ```

 ### Save

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.save
     Symbol.tojson
     Symbol.debug_str
 ```

 ### Miscellaneous

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Symbol.clip
     Symbol.sign
 ```

 ## Symbol creation routines

 ```eval_rst
 .. autosummary::
     :nosignatures:

     var
     zeros
     zeros_like
     ones
     ones_like
     arange
 ```

 ## Symbol manipulation routines

 ### Changing shape and type

 ```eval_rst
 .. autosummary::
     :nosignatures:

     cast
     reshape
     flatten
     expand_dims
 ```

 ### Expanding elements

 ```eval_rst
 .. autosummary::
     :nosignatures:

     broadcast_to
     broadcast_axes
     repeat
     tile
     pad
 ```

 ### Rearranging elements

 ```eval_rst
 .. autosummary::
     :nosignatures:

     transpose
     swapaxes
     flip
 ```

 ### Joining and splitting symbols

 ```eval_rst
 .. autosummary::
     :nosignatures:

     concat
     split
 ```

 ### Indexing routines

 ```eval_rst
 .. autosummary::
     :nosignatures:

     slice
     slice_axis
     take
     batch_take
     one_hot
     pick
     where
 ```

 ## Mathematical functions

 ### Arithmetic operations

 ```eval_rst
 .. autosummary::
     :nosignatures:

     broadcast_add
     broadcast_sub
     broadcast_mul
     broadcast_div
     broadcast_mod
     negative
     reciprocal
     dot
     batch_dot
     add_n
 ```

 ### Trigonometric functions

 ```eval_rst
 .. autosummary::
     :nosignatures:

     sin
     cos
     tan
     arcsin
     arccos
     arctan
     hypot
     broadcast_hypot
     degrees
     radians
 ```

 ### Hyperbolic functions

 ```eval_rst
 .. autosummary::
     :nosignatures:

     sinh
     cosh
     tanh
     arcsinh
     arccosh
     arctanh
 ```

 ### Reduce functions

 ```eval_rst
 .. autosummary::
     :nosignatures:

     sum
     nansum
     prod
     nanprod
     mean
     max
     min
     norm
 ```

 ### Rounding

 ```eval_rst
 .. autosummary::
     :nosignatures:

     round
     rint
     fix
     floor
     ceil
     trunc
 ```


 ### Exponents and logarithms

 ```eval_rst
 .. autosummary::
     :nosignatures:

     exp
     expm1
     log
     log10
     log2
     log1p
 ```

 ### Powers

 ```eval_rst
 .. autosummary::
     :nosignatures:

     broadcast_power
     sqrt
     rsqrt
     cbrt
     rcbrt
     square
 ```

 ### Logic functions

 ```eval_rst
 .. autosummary::
     :nosignatures:

     broadcast_equal
     broadcast_not_equal
     broadcast_greater
     broadcast_greater_equal
     broadcast_lesser
     broadcast_lesser_equal
 ```
 ### Random sampling

 ```eval_rst
 .. autosummary::
     :nosignatures:

     random_uniform
     random_normal
     random_gamma
     random_exponential
     random_poisson
     random_negative_binomial
     random_generalized_negative_binomial
     sample_uniform
     sample_normal
     sample_gamma
     sample_exponential
     sample_poisson
     sample_negative_binomial
     sample_generalized_negative_binomial
     mxnet.random.seed
 ```

 ### Sorting and searching

 ```eval_rst
 .. autosummary::
     :nosignatures:

     sort
     topk
     argsort
     argmax
     argmin
 ```

 ### Linear Algebra

 ```eval_rst
 .. autosummary::
     :nosignatures:

     linalg_gemm
     linalg_gemm2
     linalg_potrf
     linalg_potri
     linalg_trmm
     linalg_trsm
     linalg_sumlogdiag
 ```

 ### Miscellaneous

 ```eval_rst
 .. autosummary::
     :nosignatures:

     maximum
     minimum
     broadcast_maximum
     broadcast_minimum
     clip
     abs
     sign
     gamma
     gammaln
 ```

 ## Neural network

 ### Basic

 ```eval_rst
 .. autosummary::
     :nosignatures:

     FullyConnected
     Convolution
     Activation
     BatchNorm
     Pooling
     SoftmaxOutput
     softmax
     log_softmax
 ```

 ### More

 ```eval_rst
 .. autosummary::
     :nosignatures:

     Correlation
     Deconvolution
     RNN
     Embedding
     LeakyReLU
     InstanceNorm
     L2Normalization
     LRN
     ROIPooling
     SoftmaxActivation
     Dropout
     BilinearSampler
     GridGenerator
     UpSampling
     SpatialTransformer
     LinearRegressionOutput
     LogisticRegressionOutput
     MAERegressionOutput
     SVMOutput
     softmax_cross_entropy
     smooth_l1
     IdentityAttachKLSparseReg
     MakeLoss
     BlockGrad
     Custom
 ```

 ## Contrib

 ```eval_rst
 .. warning:: This package contains experimental APIs and may change in the near future.
 ```

 The `contrib.symbol` module contains many useful experimental APIs for new features. This is a place for the community to try out the new features, so that feature contributors can receive feedback.

 ```eval_rst
 .. currentmodule:: mxnet.contrib.symbol

 .. autosummary::
     :nosignatures:

     CTCLoss
     DeformableConvolution
     DeformablePSROIPooling
     MultiBoxDetection
     MultiBoxPrior
     MultiBoxTarget
     MultiProposal
     PSROIPooling
     Proposal
     count_sketch
     ctc_loss
     dequantize
     fft
     ifft
     quantize
 ```

 ## API Reference

 <script type="text/javascript" src='../../_static/js/auto_module_index.js'></script>

 ```eval_rst

 .. autoclass:: mxnet.symbol.Symbol
     :members:
     :special-members:

 .. automodule:: mxnet.symbol
     :members:
     :imported-members:
     :special-members:
     :exclude-members: Symbol

 .. automodule:: mxnet.contrib.symbol
     :members:

 ```

 <script>auto_index("api-reference");</script>
	# Symbol API

	```eval_rst
	.. currentmodule:: mxnet.symbol
	```

	## Overview

	This document lists the routines of the symbolic expression package:

	```eval_rst
	.. autosummary::
	:nosignatures:

	mxnet.symbol
	```

	The `Symbol` API, defined in the `symbol` (or simply `sym`) package, provides
	neural network graphs and auto-differentiation.
	A symbol represents a multi-output symbolic expression.
	They are composited by operators, such as simple matrix operations (e.g. “+”),
	or a neural network layer (e.g. convolution layer).
	An operator can take several input variables,
	produce more than one output variables, and have internal state variables.
	A variable can be either free, which we can bind with value later,
	or an output of another symbol.

	```python
	>>> a = mx.sym.Variable('a')
	>>> b = mx.sym.Variable('b')
	>>> c = 2 * a + b
	>>> type(c)
	<class 'mxnet.symbol.Symbol'>
	>>> e = c.bind(mx.cpu(), {'a': mx.nd.array([1,2]), 'b':mx.nd.array([2,3])})
	>>> y = e.forward()
	>>> y
	[<NDArray 2 @cpu(0)>]
	>>> y[0].asnumpy()
	array([ 4., 7.], dtype=float32)
	```

	A detailed tutorial is available at [Symbol - Neural network graphs and auto-differentiation](http://mxnet.io/tutorials/basic/symbol.html).
	<br><br>

	```eval_rst

	.. note:: most operators provided in ``symbol`` are similar to those in ``ndarray``
	although there are few differences:

	- ``symbol`` adopts declarative programming. In other words, we need to first
	compose the computations, and then feed it with data for execution whereas
	ndarray adopts imperative programming.

	- Most binary operators in ``symbol`` such as ``+`` and ``>`` don't broadcast.
	We need to call the broadcast version of the operator such as ``broadcast_plus``
	explicitly.
	```

	In the rest of this document, we first overview the methods provided by the
	`symbol.Symbol` class, and then list other routines provided by the
	`symbol` package.

	## The `Symbol` class

	### Composition

	Composite multiple symbols into a new one by an operator.

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.__call__
	```

	#### Arithmetic operations

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.__add__
	Symbol.__sub__
	Symbol.__rsub__
	Symbol.__neg__
	Symbol.__mul__
	Symbol.__div__
	Symbol.__rdiv__
	Symbol.__mod__
	Symbol.__rmod__
	Symbol.__pow__
	```

	#### Comparison operators

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.__lt__
	Symbol.__le__
	Symbol.__gt__
	Symbol.__ge__
	Symbol.__eq__
	Symbol.__ne__
	```

	### Symbol creation

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.zeros_like
	Symbol.ones_like
	```

	### Changing shape and type

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.astype
	Symbol.reshape
	Symbol.flatten
	Symbol.expand_dims
	```

	### Expanding elements

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.broadcast_to
	Symbol.broadcast_axes
	Symbol.tile
	Symbol.pad
	```

	### Rearranging elements

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.transpose
	Symbol.swapaxes
	Symbol.flip
	```

	### Reduce functions

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.sum
	Symbol.nansum
	Symbol.prod
	Symbol.nanprod
	Symbol.mean
	Symbol.max
	Symbol.min
	Symbol.norm
	```

	### Rounding

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.round
	Symbol.rint
	Symbol.fix
	Symbol.floor
	Symbol.ceil
	Symbol.trunc
	```

	### Sorting and searching

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.sort
	Symbol.argsort
	Symbol.topk
	Symbol.argmax
	Symbol.argmin
	```

	### Query information

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.name
	Symbol.list_arguments
	Symbol.list_outputs
	Symbol.list_auxiliary_states
	Symbol.list_attr
	Symbol.attr
	Symbol.attr_dict
	```

	### Indexing

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.slice
	Symbol.slice_axis
	Symbol.take
	Symbol.one_hot
	Symbol.pick
	```

	### Get internal and output symbol

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.__getitem__
	Symbol.__iter__
	Symbol.get_internals
	Symbol.get_children
	```

	### Inference type and shape

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.infer_type
	Symbol.infer_shape
	Symbol.infer_shape_partial
	```


	### Bind

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.bind
	Symbol.simple_bind
	```

	### Save

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.save
	Symbol.tojson
	Symbol.debug_str
	```

	### Miscellaneous

	```eval_rst
	.. autosummary::
	:nosignatures:

	Symbol.clip
	Symbol.sign
	```

	## Symbol creation routines

	```eval_rst
	.. autosummary::
	:nosignatures:

	var
	zeros
	zeros_like
	ones
	ones_like
	arange
	```

	## Symbol manipulation routines

	### Changing shape and type

	```eval_rst
	.. autosummary::
	:nosignatures:

	cast
	reshape
	flatten
	expand_dims
	```

	### Expanding elements

	```eval_rst
	.. autosummary::
	:nosignatures:

	broadcast_to
	broadcast_axes
	repeat
	tile
	pad
	```

	### Rearranging elements

	```eval_rst
	.. autosummary::
	:nosignatures:

	transpose
	swapaxes
	flip
	```

	### Joining and splitting symbols

	```eval_rst
	.. autosummary::
	:nosignatures:

	concat
	split
	```

	### Indexing routines

	```eval_rst
	.. autosummary::
	:nosignatures:

	slice
	slice_axis
	take
	batch_take
	one_hot
	pick
	where
	```

	## Mathematical functions

	### Arithmetic operations

	```eval_rst
	.. autosummary::
	:nosignatures:

	broadcast_add
	broadcast_sub
	broadcast_mul
	broadcast_div
	broadcast_mod
	negative
	reciprocal
	dot
	batch_dot
	add_n
	```

	### Trigonometric functions

	```eval_rst
	.. autosummary::
	:nosignatures:

	sin
	cos
	tan
	arcsin
	arccos
	arctan
	hypot
	broadcast_hypot
	degrees
	radians
	```

	### Hyperbolic functions

	```eval_rst
	.. autosummary::
	:nosignatures:

	sinh
	cosh
	tanh
	arcsinh
	arccosh
	arctanh
	```

	### Reduce functions

	```eval_rst
	.. autosummary::
	:nosignatures:

	sum
	nansum
	prod
	nanprod
	mean
	max
	min
	norm
	```

	### Rounding

	```eval_rst
	.. autosummary::
	:nosignatures:

	round
	rint
	fix
	floor
	ceil
	trunc
	```


	### Exponents and logarithms

	```eval_rst
	.. autosummary::
	:nosignatures:

	exp
	expm1
	log
	log10
	log2
	log1p
	```

	### Powers

	```eval_rst
	.. autosummary::
	:nosignatures:

	broadcast_power
	sqrt
	rsqrt
	cbrt
	rcbrt
	square
	```

	### Logic functions

	```eval_rst
	.. autosummary::
	:nosignatures:

	broadcast_equal
	broadcast_not_equal
	broadcast_greater
	broadcast_greater_equal
	broadcast_lesser
	broadcast_lesser_equal
	```
	### Random sampling

	```eval_rst
	.. autosummary::
	:nosignatures:

	random_uniform
	random_normal
	random_gamma
	random_exponential
	random_poisson
	random_negative_binomial
	random_generalized_negative_binomial
	sample_uniform
	sample_normal
	sample_gamma
	sample_exponential
	sample_poisson
	sample_negative_binomial
	sample_generalized_negative_binomial
	mxnet.random.seed
	```

	### Sorting and searching

	```eval_rst
	.. autosummary::
	:nosignatures:

	sort
	topk
	argsort
	argmax
	argmin
	```

	### Linear Algebra

	```eval_rst
	.. autosummary::
	:nosignatures:

	linalg_gemm
	linalg_gemm2
	linalg_potrf
	linalg_potri
	linalg_trmm
	linalg_trsm
	linalg_sumlogdiag
	```

	### Miscellaneous

	```eval_rst
	.. autosummary::
	:nosignatures:

	maximum
	minimum
	broadcast_maximum
	broadcast_minimum
	clip
	abs
	sign
	gamma
	gammaln
	```

	## Neural network

	### Basic

	```eval_rst
	.. autosummary::
	:nosignatures:

	FullyConnected
	Convolution
	Activation
	BatchNorm
	Pooling
	SoftmaxOutput
	softmax
	log_softmax
	```

	### More

	```eval_rst
	.. autosummary::
	:nosignatures:

	Correlation
	Deconvolution
	RNN
	Embedding
	LeakyReLU
	InstanceNorm
	L2Normalization
	LRN
	ROIPooling
	SoftmaxActivation
	Dropout
	BilinearSampler
	GridGenerator
	UpSampling
	SpatialTransformer
	LinearRegressionOutput
	LogisticRegressionOutput
	MAERegressionOutput
	SVMOutput
	softmax_cross_entropy
	smooth_l1
	IdentityAttachKLSparseReg
	MakeLoss
	BlockGrad
	Custom
	```

	## Contrib

	```eval_rst
	.. warning:: This package contains experimental APIs and may change in the near future.
	```

	The `contrib.symbol` module contains many useful experimental APIs for new features. This is a place for the community to try out the new features, so that feature contributors can receive feedback.

	```eval_rst
	.. currentmodule:: mxnet.contrib.symbol

	.. autosummary::
	:nosignatures:

	CTCLoss
	DeformableConvolution
	DeformablePSROIPooling
	MultiBoxDetection
	MultiBoxPrior
	MultiBoxTarget
	MultiProposal
	PSROIPooling
	Proposal
	count_sketch
	ctc_loss
	dequantize
	fft
	ifft
	quantize
	```

	## API Reference

	<script type="text/javascript" src='../../_static/js/auto_module_index.js'></script>

	```eval_rst

	.. autoclass:: mxnet.symbol.Symbol
	:members:
	:special-members:

	.. automodule:: mxnet.symbol
	:members:
	:imported-members:
	:special-members:
	:exclude-members: Symbol

	.. automodule:: mxnet.contrib.symbol
	:members:

	```

	<script>auto_index("api-reference");</script>