From d1c85455e66fd514584d2d0bd0dbd9ebecefcf2e Mon Sep 17 00:00:00 2001
From: William Ball <wball1@swarthmore.edu>
Date: Mon, 27 Jul 2020 12:17:05 -0700
Subject: [PATCH] optimizations

---
 rust/fourthfree/Cargo.toml  | 2 +-
 rust/fourthfree/src/main.rs | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/rust/fourthfree/Cargo.toml b/rust/fourthfree/Cargo.toml
index ed6ff3b..791dc62 100644
--- a/rust/fourthfree/Cargo.toml
+++ b/rust/fourthfree/Cargo.toml
@@ -7,4 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rug = "1.10.0"
+rayon = "1.1"
diff --git a/rust/fourthfree/src/main.rs b/rust/fourthfree/src/main.rs
index c7d0104..e30a2d0 100644
--- a/rust/fourthfree/src/main.rs
+++ b/rust/fourthfree/src/main.rs
@@ -1,7 +1,9 @@
+use rayon::prelude::*;
+
 // use std::thread;
 
 // const NUM_THREADS: usize = 12;
-const BASE: u64 = 2;
+const BASE: u64 = 10;
 
 fn is_fourth_free(x: &u64) -> bool {
     let mut i = 2;
@@ -25,7 +27,7 @@ fn step(x: &u64) -> Vec<u64> {
 }
 
 fn next(ls: Vec<u64>) -> Vec<u64> {
-    ls.iter().map(step).flatten().collect()
+    ls.par_iter().map(step).flatten().collect()
 }
 
 // fn next(ls: Vec<u64>) -> Vec<u64> {
@@ -62,7 +64,7 @@ fn main() {
     loop {
         i += 1;
         val += ls.len() as f64 / 2u64.pow(i) as f64;
-        ls = next(ls);
         println!("{}\t{}\t{}", i, ls.len(), val);
+        ls = next(ls);
     }
 }