Accessing tuple elements in parallel

In this recipe, we will cover how to access elements of a tuple in parallel.

How to do it…

1. Import the built-in package as follows:

   import Control.Parallel.Strategies

2. Evaluate the expression in a tuple in parallel. We perform this task twice with different strategies to demonstrate how strategies are easily swapped to change the parallel nature of the code as follows:

   main = do
     let (a, b) = withStrategy (parTuple2 rseq rseq) (task1, task2)
     print $ seq (a+b) "done 1"
     let (a, bs) = withStrategy (parTuple2 rseq rdeepseq) (task1, tasks)
     print $ seq (a + sum bs) "done 2"

3. Define time-consuming tasks as follows:

   task1 = 8^8^8 :: Integer
   task2 = 8^8^8 :: Integer
   tasks = [10^10..10^10+10000] :: [Integer]

4. Compile the code with the threaded and rtsopts flags enabled, as follows:

   $ ghc -O2 --make Main.hs -threaded -rtsopts
   

5. Run it by specifying the number of cores as follows:

   $ ./Main +RTS -N2
   

There's more…

When dealing with tuples...