From 49d4f20b18e24003e64c71a81b558f86cc1cda0e Mon Sep 17 00:00:00 2001
From: Bill Ewanick <bill@ewanick.com>
Date: Tue, 5 Aug 2025 09:18:33 -0400
Subject: [PATCH] Make computation parallel

---
 flake.nix        |  1 +
 src/3n+1/Main.hs | 16 ++++++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/flake.nix b/flake.nix
index b696281..0f1a197 100644
--- a/flake.nix
+++ b/flake.nix
@@ -51,6 +51,7 @@
               # maths
               primes
               arithmoi
+              parallel
 
               # graphing libraries!
               # Chart
diff --git a/src/3n+1/Main.hs b/src/3n+1/Main.hs
index e896518..e69c59c 100644
--- a/src/3n+1/Main.hs
+++ b/src/3n+1/Main.hs
@@ -3,13 +3,21 @@ The Simplest Math Problem No One Can Solve - Collatz Conjecture
 https://youtu.be/094y1Z2wpJg
 -}
 
-import           Data.Set    (fromList)
-import           Debug.Trace (trace)
+import           Control.Parallel.Strategies
+import           Data.Containers.ListUtils
+import           Debug.Trace                 (trace)
 
 main :: IO ()
 main = do
-  let results = map f [10^1_000..10^1_000+100] :: [Integer]
-  print (fromList results)
+  let start = 2^1_000_000
+  let end = 100
+  -- let message = "Starting at " <> show start <> ", and computing " <> show end <> " values."
+  let message = "Starting at 2^1_000_000, and computing " <> show end <> " values."
+  let results = parMap rpar f [start..start+end] :: [Integer]
+  putStrLn "======================================"
+  putStrLn message
+  print $ nubOrd results
+  putStrLn "======================================"
 
 lst :: [Integer]
 lst = take 300 [2^100_000..]