# Documentation or examples for function based interface

**URL:** <https://discourse.pumas.ai/t/documentation-or-examples-for-function-based-interface/397>\
**Category:** Usage\
**Created:** [August 17, 2020, 2:46pm UTC](https://discourse.pumas.ai/t/documentation-or-examples-for-function-based-interface/397 "2020-08-17T14:46:20Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sstodtmann](https://avatars.discourse-cdn.com/v4/letter/s/b5ac83/32.png) [@sstodtmann](https://discourse.pumas.ai/u/sstodtmann)\
**Post date:** [August 17, 2020, 2:46pm UTC](https://discourse.pumas.ai/t/documentation-or-examples-for-function-based-interface/397/1 "2020-08-17T14:46:21Z")

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Hi,  
I have seen multiple references in the docs to the “function based interface”, which is what apparently allows the use more of more varied problem types. Is there any documentation or examples out there that can help me get started with the function based interface?  
Even better, I would be grateful if someone can share an example of a PUMAS model where a flexible function approximator (such as a NN, but I’d also be happy with a spline or fractional polynomial for starters) is used in the dynamics part.  
Thanks,  
Sven

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**Author:** ![vijay](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.pumas.ai/vijay/32/96_2.png) [@vijay](https://discourse.pumas.ai/u/vijay)\
**Post date:** [August 17, 2020, 3:46pm UTC](https://discourse.pumas.ai/t/documentation-or-examples-for-function-based-interface/397/2 "2020-08-17T15:46:54Z")

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hi Sven,

the function-based interface documentation can be found here. [Pumas Function Based Interface](https://docs.pumas.ai/basics/models/#The-PumasModel-Function-Based-Interface)

We will post a complete working example of the function-based interface here.

Best,  
Vijay