Some examples of Comonad usage in programs
See this blog post for the full details: https://justinhj.github.io/2019/06/20/comonads-for-life.html
Comonad operations are nice fit for image processing methods where the value of a pixel is modified based on the values of other pixels in the image. Some examples are included such as box filtering and mirroring.
Conway's game of life involves running a rule on each cell in a grid to determine the future state of that cell, which is nicely encoded in a function that can be run with coFlatMap
This is an sbt project; build and run as follows, then choose which program to run.
sbt run
This project was created by https://github.com/justinhj/fp-starter-pack.g8
There are performed on a 2017 Macbook Pro under non-ideal conditions (bunch of Apps running)
CPU 2.5 GHz Dual-Core Intel Core i7 RAM 16 GB 2133 MHz LPDDR3
Initial benchmark
[info] Benchmark Mode Cnt Score Error Units
[info] FocusedGridBench.withMap2Large avgt 5 120145.615 ± 14792.890 us/op
[info] FocusedGridBench.withMap2Small avgt 5 52.240 ± 3.186 us/op
[info] FocusedGridBench.withSlowApLarge avgt 5 442488.978 ± 226548.518 us/op
[info] FocusedGridBench.withSlowApSmall avgt 5 119.935 ± 7.673 us/op
[success] Total time: 410 s, completed 27-Mar-2020 8:10:42 PM
Implemented and benchmarked array version
[info] Benchmark Mode Cnt Score Error Units
[info] FocusedGridArrayBench.withMap2Large avgt 5 171099.587 ± 65471.687 us/op
[info] FocusedGridArrayBench.withMap2Small avgt 5 54.418 ± 25.669 us/op
[info] FocusedGridBench.withMap2Large avgt 5 152831.655 ± 40709.521 us/op
[info] FocusedGridBench.withMap2Small avgt 5 59.168 ± 15.346 us/op
[info] FocusedGridBench.withSlowApLarge avgt 5 649442.291 ± 215248.298 us/op
[info] FocusedGridBench.withSlowApSmall avgt 5 141.025 ± 78.928 us/op
Notable that optimized map2 is 4x faster on the large image than slowAp and
the array version is actually slower than the vector version.
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