parallel_map

# parallel_map


[![Package Version](https://img.shields.io/hexpm/v/parallel_map)](https://hex.pm/packages/parallel_map)
[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/parallel_map/)

Note: This package only works for the erlang target.

This is a simple gleam library that adds a `iterator_pmap` and `list_pmap`,
which has a similar behaviour and interface as `iterator.map` and `list.map`,
except it runs in parallel by spawning extra processes to do the work.

There is also `iterator_find_pmap` and `list_find_pmap` which stop the whole
parallel execution after finding the first **Ok** value.

```sh

gleam add parallel_map

```

```gleam

import gleam/list

import gleam/iterator

import gleam/result

import parallel_map.{MatchSchedulers, WorkerAmount}



pub fn main() {

  let map_func = fn(a: Int) -> Int {a * a}



  let iterator_input = iterator.range(0, 1000)



  iterator_input

  |> iterator.map(map_func)



  // can be rewritten as

  iterator_input

  |> parallel_map.iterator_pmap(map_func, WorkerAmount(16), 100)

  |> iterator.map(result.unwrap(_, -1))



  let list_input = list.range(0, 1000)



  list_input

  |> list.map(map_func)



  // can be rewritten as

  list_input

  |> parallel_map.list_pmap(map_func, MatchSchedulersOnline, 100)

  |> list.map(result.unwrap(_, -1))





  // there is also

  //   parallel_map.iterator_find_pmap similar to iterator.find_map

  //   parallel_map.list_find_pmap similar to list.find_map,

  // which stop the works after finding the first Ok value.



  let find_map_func = fn(a: Int) -> Result(Int, Int) {

    case a {

      x if x > 500 -> Ok(x * 2)

      _ -> Error(a)

    }

  }



  iterator_input

  |> iterator.find_map(find_map_func)



  // can be rewritten as

  iterator_input

  |> parallel_map.iterator_find_pmap(find_map_func, WorkerAmount(16), 100)





  list_input

  |> list.find_map(find_map_func)



  // can be rewritten as

  list_input

  |> parallel_map.list_find_pmap(find_map_func, MatchSchedulersOnline, 100)

}

```


Further documentation can be found at <https://hexdocs.pm/parallel_map>.

## Development


```sh

gleam run   # Run the project

gleam test  # Run the tests

gleam shell # Run an Erlang shell

```