# GRIN

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The name GRIN is short for *Graph Reduction Intermediate Notation*, and it is an intermediate language for graph reduction.
For an overview read
<a href="http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/The GRIN Project.pdf">
The GRIN Project
</a> article. To grasp the details take your time and read Urban Boquist's PhD thesis on
<a href="http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf">
Code Optimisation Techniques for Lazy Functional Languages
</a>.  
Also check the performance [benchmark](https://rawgit.com/andorp/grin/master/grin/grin-benchmark.html).

<a href="http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=41">
<img src="https://raw.githubusercontent.com/andorp/grin/master/images/grin-syntax.png" width="500" >
</a>

## Simplifying Transformations

Transformation | Schema
-------------- | ------
[vectorisation][113]                <br><br> _source code:_ <br> [Vectorisation2.hs]       | [<img src="images/vectorisation.png"         width="500">][113]
[case simplification][116]          <br><br> _source code:_ <br> [CaseSimplification.hs]   | [<img src="images/case-simplification.png"   width="500">][116]
[split fetch operation][118]        <br><br> _source code:_ <br> [SplitFetch.hs]           | [<img src="images/split-fetch-operation.png" width="500">][118]
[right hoist fetch operation][123]  <br><br> _source code:_ <br> [RightHoistFetch2.hs]     | [<img src="images/right-hoist-fetch.png"     width="500">][123]
[register introduction][126]        <br><br> _source code:_ <br> [RegisterIntroduction.hs] | [<img src="images/register-introduction.png" width="500">][126]


[113]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=113
[116]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=116
[118]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=118
[123]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=123
[126]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=126

[Vectorisation2.hs]:        https://github.com/andorp/grin/blob/master/grin/src/Transformations/Simplifying/Vectorisation2.hs
[CaseSimplification.hs]:    https://github.com/andorp/grin/blob/master/grin/src/Transformations/Simplifying/CaseSimplification.hs
[SplitFetch.hs]:            https://github.com/andorp/grin/blob/master/grin/src/Transformations/Simplifying/SplitFetch.hs
[RightHoistFetch2.hs]:      https://github.com/andorp/grin/blob/master/grin/src/Transformations/Simplifying/RightHoistFetch2.hs
[RegisterIntroduction.hs]:  https://github.com/andorp/grin/blob/master/grin/src/Transformations/Simplifying/RegisterIntroduction.hs


## Optimising Transformations

Transformation | Schema
-------------- | ------
[evaluated case elimination][141]         <br><br> _source code:_ <br> [EvaluatedCaseElimination.hs]  | [<img src="images/evaluated-case-elimination.png" width="500">][141]
[trivial case elimination][142]           <br><br> _source code:_ <br> [TrivialCaseElimination.hs]    | [<img src="images/trivial-case-elimination.png"   width="500">][142]
[sparse case optimisation][143]           <br><br> _source code:_ <br> [SparseCaseOptimisation.hs]    | [<img src="images/sparse-case-optimisation.png"   width="500">][143]
[update elimination][148]                 <br><br> _source code:_ <br> [UpdateElimination.hs]         | [<img src="images/update-elimination.png"         width="500">][148]
[copy propagation][129]                   <br><br> _source code:_ <br> [CopyPropagation.hs]           | [<img src="images/copy-propagation-left.png"      width="500"><img src="images/copy-propagation-right.png" width="500">][129]
[late inlining][151]                      <br><br> _source code:_ <br> [Inlining.hs]                  | [<img src="images/late-inlining.png"              width="500">][151]
[generalised unboxing][134]               <br><br> _source code:_ <br> __TODO__                       | [<img src="images/generalised-unboxing.png"       width="500"><img src="images/unboxing-of-function-return-values.png" width="500">][134]
[arity raising][160]                      <br><br> _source code:_ <br> __TODO__                       | [<img src="images/arity-raising.png"              width="500">][160]
[case copy propagation][144]              <br><br> _source code:_ <br> [CaseCopyPropagation.hs]       | [<img src="images/case-copy-propagation.png"      width="500">][144]
[case hoisting][153]                      <br><br> _source code:_ <br> __TODO__                       | [<img src="images/case-hoisting.png"              width="500">][153]
[whnf update elimination][149]            <br><br> _source code:_ <br> __TODO__                       | [<img src="images/whnf-update-elimination.png"    width="500">][149]
[common sub-expression elimination][164]  <br><br> _source code:_ <br> [CSE.hs]                       | [<img src="images/common-sub-expression-elimination-1.png" width="500"><img src="images/common-sub-expression-elimination-2.png" width="500">][164]
[constant propagation][159]               <br><br> _source code:_ <br> [ConstantPropagation.hs]       | 
[dead procedure elimination][169]         <br><br> _source code:_ <br> [DeadProcedureElimination.hs]  | 
[dead variable elimination][170]          <br><br> _source code:_ <br> [DeadVariableElimination.hs]   | 
[dead parameter elimination][171]         <br><br> _source code:_ <br> __TODO__                       | 

[129]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=129
[134]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=134
[141]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=141
[142]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=142
[143]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=143
[144]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=144
[148]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=148
[149]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=149
[151]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=151
[153]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=153
[159]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=159
[160]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=160
[164]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=164
[169]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=169
[170]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=170
[171]: http://nbviewer.jupyter.org/github/andorp/grin/blob/master/papers/boquist.pdf#page=171

[ConstantPropagation.hs]:       https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/ConstantPropagation.hs
[CopyPropagation.hs]:           https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/CopyPropagation.hs
[CaseCopyPropagation.hs]:       https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/CaseCopyPropagation.hs
[CSE.hs]:                       https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/CSE.hs
[DeadProcedureElimination.hs]:  https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/DeadProcedureElimination.hs
[DeadVariableElimination.hs]:   https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/DeadVariableElimination.hs
[EvaluatedCaseElimination.hs]:  https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/EvaluatedCaseElimination.hs
[Inlining.hs]:                  https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/Inlining.hs
[SparseCaseOptimisation.hs]:    https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/SparseCaseOptimisation.hs
[TrivialCaseElimination.hs]:    https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/TrivialCaseElimination.hs
[UpdateElimination.hs]:         https://github.com/andorp/grin/blob/master/grin/src/Transformations/Optimising/UpdateElimination.hs