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NetPrepend[net,layer]

prepends a layer or a net onto a NetChain, a layer or a NetGraph with one input port.

NetPrepend[net,"name"layer]

appends a layer with a given name.

NetPrepend[net,{layer1,layer2,…}]

prepends several layers or nets.

Details and Options
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Options  
"Input"  
"Output"  
Possible Issues  
See Also
Tech Notes
Related Guides
History
Cite this Page

NetPrepend

NetPrepend[net,layer]

prepends a layer or a net onto a NetChain, a layer or a NetGraph with one input port.

NetPrepend[net,"name"layer]

appends a layer with a given name.

NetPrepend[net,{layer1,layer2,…}]

prepends several layers or nets.

Details and Options

  • The output of the prepended layer must be compatible with the input of the first layer in the chain.
  • Any NetEncoder attached to the end of the chain will be removed.
  • NetPrepend takes the following options:
  • "Input"Automatictype for the input of the resulting chain
    "Output"Automatictype for the output of the resulting chain
  • Options "Input" and "Output" support the normal type specifications allowed by NetChain, including NetEncoder and NetDecoder.

Examples

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Basic Examples  (3)

Prepend a layer to the start of a chain:

Prepend a named layer to the start of a chain:

Prepend several layers to the start of a chain:

Scope  (3)

Prepend a layer and attach a NetEncoder:

Create a NetChain with NetPrepend:

Prepend a layer to a NetGraph with one input:

Prepend a layer with a given name:

Options  (6)

"Input"  (4)

Set the input shape of the net:

Set a NetEncoder for the net:

Using this option is equivalent to using NetReplacePart on the returned net:

An existing NetEncoder can be added back to the returned net using this option, provided it is compatible with the new initial layer:

"Output"  (2)

Set a NetDecoder for the net:

Using this option is equivalent to using NetReplacePart on the returned net:

Possible Issues  (3)

The output of the prepended layer must be compatible with the input of the first layer in the chain:

A network with several outputs cannot be prepended:

A layer cannot be prepended to a network with more than one input:

Wolfram Research (2018), NetPrepend, Wolfram Language function, https://reference.wolfram.com/language/ref/NetPrepend.html (updated 2021).

Text

Wolfram Research (2018), NetPrepend, Wolfram Language function, https://reference.wolfram.com/language/ref/NetPrepend.html (updated 2021).

CMS

Wolfram Language. 2018. "NetPrepend." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2021. https://reference.wolfram.com/language/ref/NetPrepend.html.

APA

Wolfram Language. (2018). NetPrepend. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NetPrepend.html

BibTeX

@misc{reference.wolfram_2025_netprepend, author="Wolfram Research", title="{NetPrepend}", year="2021", howpublished="\url{https://reference.wolfram.com/language/ref/NetPrepend.html}", note=[Accessed: 14-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_netprepend, organization={Wolfram Research}, title={NetPrepend}, year={2021}, url={https://reference.wolfram.com/language/ref/NetPrepend.html}, note=[Accessed: 14-August-2025]}