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NetMapOperator
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NetMapOperator

[Experimental]

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represents a net in which net is mapped over a sequence of inputs to give a sequence of outputs.

Details and Options

  • NetMapOperator[net] represents a net that takes a sequence of arrays and outputs a sequence of the same length.
  • NetMapOperator[net] accepts a single input sequence {x1,x2,…,xn} and computes {net[x1],net[x2],…,net[xn]}.
  • In NetMapOperator[net], net should take exactly one input and produce exactly one output.
  • NetExtract can be used to extract net from a NetMapOperator[net] object.
  • The input and output ports of the net represented by NetMapOperator are:
  • "Input"a sequence of arrays
    "Output"a sequence of arrays
  • NetMapOperator[net] can be seen as allowing a form of weight sharing between multiple copies of net, one for each sequence element that is being mapped.
  • NetMapOperator[net,"Input"->shape] allows the shape of the input to be specified. Possible forms for shape are:
  • da vector of size d
    {d1,d2}a matrix of size d1×d2
    {d1,d2,…}an array of shape d1×d2×…
    {"Varying",d2,d3,…}an array whose first dimension is variable and whose remaining dimensions are d2×d3×…
  • The following training parameter can be included:
  • LearningRateMultipliersAutomaticlearning rate multipliers for trainable arrays in the net
  • NetExtract allows access to the forward and reverse nets via "Net".
  • Options[NetMapOperator] gives the list of default options to construct the operator. Options[NetMapOperator[…]] gives the list of default options to evaluate the operator on some data.
  • Information[NetMapOperator[…]] gives a report about the operator.
  • Information[NetMapOperator[…],prop] gives the value of the property prop of NetMapOperator[…]. Possible properties are the same as for NetGraph.

Examples

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Basic Examples  (2)Summary of the most common use cases

Create a NetMapOperator that maps a LinearLayer over a sequence:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-4ajk52
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Out[1]=1

Create a NetMapOperator that maps a SummationLayer over a sequence:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-psrddh
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Out[1]=1

Apply the layer to a sequence of vectors:

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In[2]:=2
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https://wolfram.com/xid/0mlfp1z4bl62-8umgqw
Direct link to example
Out[2]=2

The layer threads across a batch of sequences of different lengths:

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In[3]:=3
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https://wolfram.com/xid/0mlfp1z4bl62-q95cbk
Direct link to example
Out[3]=3

Scope  (3)Survey of the scope of standard use cases

Create a net that maps a LinearLayer over a sequence of vectors that have been one-hot encoded from the characters of a string:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-9rvweb
Direct link to example
Out[1]=1

Apply the net to some inputs:

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In[2]:=2
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https://wolfram.com/xid/0mlfp1z4bl62-xf04e1
Direct link to example
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In[3]:=3
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https://wolfram.com/xid/0mlfp1z4bl62-dzt3pz
Direct link to example

The initialized LinearLayer can be obtained using NetExtract:

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In[4]:=4
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https://wolfram.com/xid/0mlfp1z4bl62-55h8cy
Direct link to example
Out[4]=4

Create a net that maps a single pooling layer over a pair of images. First create a pooling layer that operates on images:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-11mbqp
Direct link to example
Out[1]=1
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In[2]:=2
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https://wolfram.com/xid/0mlfp1z4bl62-i15e5b
Direct link to example
Out[2]=2

Create a net that maps the pooling layer over sequences of images:

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In[3]:=3
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https://wolfram.com/xid/0mlfp1z4bl62-d9f3wn
Direct link to example
Out[3]=3
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In[4]:=4
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https://wolfram.com/xid/0mlfp1z4bl62-mhn9fy
Direct link to example
Out[4]=4

Use NetMapOperator to apply a one-dimensional pooling to each row of an image:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-454xib
Direct link to example
Out[1]=1
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In[2]:=2
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https://wolfram.com/xid/0mlfp1z4bl62-5xkdt2
Direct link to example
Out[2]=2

Applications  (1)Sample problems that can be solved with this function

Sorting lists of numbers. Generate a test and training set consisting of lists of integers between 1 and 6:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-njdc95
Direct link to example

Display three random samples drawn from the training set:

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In[2]:=2
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https://wolfram.com/xid/0mlfp1z4bl62-qfv88q
Direct link to example
Out[2]=2

Define a NetGraph with an AttentionLayer:

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In[3]:=3
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https://wolfram.com/xid/0mlfp1z4bl62-wvkti7
Direct link to example
Out[3]=3

Train the net:

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In[4]:=4
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https://wolfram.com/xid/0mlfp1z4bl62-kwgxp9
Direct link to example
Out[4]=4

Use the net to sort a list of integers:

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In[5]:=5
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https://wolfram.com/xid/0mlfp1z4bl62-zm2ga9
Direct link to example
Out[5]=5

Properties & Relations  (1)Properties of the function, and connections to other functions

NetMapOperator can be used to implement NetPairEmbeddingOperator. Create an initialized LinearLayer:

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In[1]:=1
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https://wolfram.com/xid/0mlfp1z4bl62-4a82u2
Direct link to example
Out[1]=1

Create NetPairEmbeddingOperator using the linear layer as its embedding net, and evaluate it on an input:

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In[2]:=2
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https://wolfram.com/xid/0mlfp1z4bl62-hfdlob
Direct link to example
Out[2]=2
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In[3]:=3
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https://wolfram.com/xid/0mlfp1z4bl62-iiunif
Direct link to example
Out[3]=3

Define a NetGraph with a NetMapOperator that is equivalent to the previous NetPairEmbeddingOperator, and evaluate it on the same input:

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In[4]:=4
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https://wolfram.com/xid/0mlfp1z4bl62-9lffv5
Direct link to example
Out[4]=4
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In[5]:=5
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https://wolfram.com/xid/0mlfp1z4bl62-pg1cnj
Direct link to example
Out[5]=5
Wolfram Research (2017), NetMapOperator, Wolfram Language function, https://reference.wolfram.com/language/ref/NetMapOperator.html (updated 2020).
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Wolfram Research (2017), NetMapOperator, Wolfram Language function, https://reference.wolfram.com/language/ref/NetMapOperator.html (updated 2020).

Text

Wolfram Research (2017), NetMapOperator, Wolfram Language function, https://reference.wolfram.com/language/ref/NetMapOperator.html (updated 2020).

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Wolfram Research (2017), NetMapOperator, Wolfram Language function, https://reference.wolfram.com/language/ref/NetMapOperator.html (updated 2020).

CMS

Wolfram Language. 2017. "NetMapOperator." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/NetMapOperator.html.

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Wolfram Language. 2017. "NetMapOperator." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/NetMapOperator.html.

APA

Wolfram Language. (2017). NetMapOperator. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NetMapOperator.html

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Wolfram Language. (2017). NetMapOperator. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NetMapOperator.html

BibTeX

@misc{reference.wolfram_2025_netmapoperator, author="Wolfram Research", title="{NetMapOperator}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/NetMapOperator.html}", note=[Accessed: 06-April-2025 ]}

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@misc{reference.wolfram_2025_netmapoperator, author="Wolfram Research", title="{NetMapOperator}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/NetMapOperator.html}", note=[Accessed: 06-April-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_netmapoperator, organization={Wolfram Research}, title={NetMapOperator}, year={2020}, url={https://reference.wolfram.com/language/ref/NetMapOperator.html}, note=[Accessed: 06-April-2025 ]}

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@online{reference.wolfram_2025_netmapoperator, organization={Wolfram Research}, title={NetMapOperator}, year={2020}, url={https://reference.wolfram.com/language/ref/NetMapOperator.html}, note=[Accessed: 06-April-2025 ]}