finished rust impl

rust/Cargo.toml

@@ -9,5 +9,3 @@ edition = "2021"
 rayon = "1.5.1"
 rand = "0.8.5"
 
-[dev-dependencies]
-quickcheck = "0.8.0"

rust/src/main.rs

@@ -1,18 +1,134 @@
-use std::fs;
+#![feature(test)]
 
-fn main() {
-    let input = fs::read_to_string("../data/perm50e6.txt")
-        .expect("Could not read file")
-        .lines()
-        .map(|s| s.parse::<u64>().unwrap())
-        .collect::<Vec<u64>>();
+use rayon::join;
 
-    // println!("{}", input.len());
-    // let input = vec![100, 32, 57, 10];
-}
-
-fn Cqsort<T>(s: &Vec<T>) {
-    if s.len() <= 1 {
-        return;
+fn choose_pivot<T: Ord>(slice: &[T]) -> usize {
+    // if slice.len() <= 2 {return slice.len() - 1;};
+    let (mut ismall, imid, mut ibig) = (0, slice.len() / 2, slice.len() - 1);
+    if slice[ibig] < slice[ismall] {
+        std::mem::swap(&mut ibig, &mut ismall);
+    }
+    if slice[imid] <= slice[ismall] {
+        ismall
+    } else if slice[ibig] <= slice[imid] {
+        ibig
+    } else {
+        imid
     }
 }
+
+/// choose a pivot, then reorder so that everything to the left of the pivot is smaller, and
+/// everything to the right is greater
+/// Assumes slice.len() > 2
+fn partition<T: Ord>(slice: &mut [T], pivot: usize) -> usize {
+    let mxix = slice.len() - 1;
+    slice.swap(pivot, mxix);
+    let (mut left, mut right) = (0, mxix - 1);
+
+    while left < right {
+        if slice[left] <= slice[mxix] {
+            left += 1;
+        } else if slice[right] >= slice[mxix] {
+            right -= 1;
+        } else {
+            slice.swap(left, right);
+            left += 1;
+            right -= 1;
+        }
+    }
+
+    if left > right {
+        // We just swapped the final two.
+        slice.swap(left, mxix);
+        return left;
+    }
+
+    // Left and right met.
+    if slice[left] >= slice[mxix] {
+        slice.swap(left, mxix);
+        return left;
+    } else if slice[left] <= slice[mxix] {
+        slice.swap(left + 1, mxix);
+        return left + 1;
+    }
+
+    panic!(
+        "This should be unreachable. Indices: {}, {} / {}",
+        left, right, mxix
+    );
+}
+
+fn quicksort<T: Ord + std::marker::Send>(slice: &mut [T]) {
+    if slice.len() <= 1 {
+        return;
+    } else if slice.len() == 2 {
+        if slice[0] >= slice[1] {
+            slice.swap(0, 1);
+        }
+        return;
+    }
+
+    let pivot = choose_pivot(slice);
+    let pivot = partition(slice, pivot);
+    let (left_slice, right_slice) = slice.split_at_mut(pivot);
+
+    let right_slice = &mut right_slice[1..];
+
+    quicksort(left_slice);
+    quicksort(right_slice);
+}
+
+fn par_quicksort<T: Ord + std::marker::Send>(slice: &mut [T]) {
+    if slice.len() <= 1 {
+        return;
+    } else if slice.len() == 2 {
+        if slice[0] >= slice[1] {
+            slice.swap(0, 1);
+        }
+        return;
+    }
+
+    let pivot = choose_pivot(slice);
+    let pivot = partition(slice, pivot);
+    let (left_slice, right_slice) = slice.split_at_mut(pivot);
+    // left_slice is [0 - pivot-1], right_slice is [pivot, end]. We don't want to include the
+    // pivot, so reassign right_slice
+    let right_slice = &mut right_slice[1..];
+
+    join(|| quicksort(left_slice), || quicksort(right_slice));
+}
+
+use rand::distributions::{Distribution, Uniform};
+use rand::thread_rng;
+fn main() {
+    let mut s: Vec<i32> = Uniform::from(0..1_000_000_000)
+        .sample_iter(&mut thread_rng())
+        .take(100_000)
+        .collect();
+
+    quicksort(&mut s);
+}
+
+extern crate test;
+use test::Bencher;
+fn get_bench_vec() -> Vec<i32> {
+    let s = Uniform::from(0..1_000_000_000)
+        .sample_iter(&mut thread_rng())
+        .take(500_000)
+        .collect();
+    return s;
+}
+
+#[bench]
+fn par_qs(b: &mut Bencher) {
+    let mut test_vec = get_bench_vec();
+
+    b.iter(|| par_quicksort(&mut test_vec))
+}
+
+#[bench]
+fn qs(b: &mut Bencher) {
+    let mut test_vec = get_bench_vec();
+
+    b.iter(|| quicksort(&mut test_vec))
+}

rust/src/original.rs

@@ -1,156 +0,0 @@
-use rayon::join;
-
-fn partition<T, F>(d: &mut [T], is_less: &F) -> usize
-where
-    F: Fn(&T, &T) -> bool,
-{
-    d.swap(0, d.len() / 2);
-    let mut mid = 0;
-    for i in 1..d.len() {
-        if is_less(&d[i], &d[0]) {
-            mid += 1;
-            d.swap(i, mid);
-        }
-    }
-    d.swap(0, mid);
-    mid
-}
-
-fn insert_sort<T, F>(d: &mut [T], is_less: &F)
-where
-    F: Fn(&T, &T) -> bool,
-{
-    for i in 1..d.len() {
-        let mut n = i;
-        while n > 0 && is_less(&d[n], &d[n - 1]) {
-            d.swap(n, n - 1);
-            n -= 1;
-        }
-    }
-}
-
-fn quick_sort<T, F>(d: &mut [T], is_less: &F)
-where
-    F: Fn(&T, &T) -> bool,
-{
-    if d.len() > 30 {
-        let mut mid = partition(d, is_less);
-        if mid < d.len() / 2 {
-            mid += 1;
-        }
-        let (left, right) = d.split_at_mut(mid);
-        quick_sort(left, is_less);
-        quick_sort(right, is_less);
-    } else {
-        insert_sort(d, is_less);
-    }
-}
-
-fn par_quick_sort<T, F>(d: &mut [T], is_less: &F)
-where
-    F: Fn(&T, &T) -> bool + Send + Sync,
-    T: Send,
-{
-    if d.len() > 30 {
-        let mut mid = partition(d, is_less);
-        if mid < d.len() / 2 {
-            mid += 1;
-        }
-        let (left, right) = d.split_at_mut(mid);
-
-        if right.len() > 100_000 {
-            join(
-                || par_quick_sort(left, is_less),
-                || par_quick_sort(right, is_less),
-            );
-        } else {
-            quick_sort(left, is_less);
-            quick_sort(right, is_less);
-        }
-    } else {
-        insert_sort(d, is_less);
-    }
-}
-
-pub trait QSort<T> {
-    fn qsort(&mut self);
-
-    fn is_sorted(&self) -> bool;
-}
-
-impl<T> QSort<T> for [T]
-where
-    T: Ord,
-{
-    fn qsort(&mut self) {
-        quick_sort(self, &|a: &T, b: &T| a.lt(b));
-    }
-
-    fn is_sorted(&self) -> bool {
-        self.windows(2).all(|w| w[0] <= w[1])
-    }
-}
-
-pub trait ParQSort<T> {
-    fn par_qsort(&mut self);
-}
-
-impl<T> ParQSort<T> for [T]
-where
-    T: Ord + Send,
-{
-    fn par_qsort(&mut self) {
-        par_quick_sort(self, &|a: &T, b: &T| a.lt(b));
-    }
-}
-
-use rand::distributions::{Distribution, Uniform};
-use rand::thread_rng;
-use rayon::prelude::*;
-use std::time::Instant;
-
-fn main() {
-    let len = 50_000_000;
-    let orig: Vec<i32> = Uniform::from(0..1_000_000_000)
-        .sample_iter(&mut thread_rng())
-        .take(len)
-        .collect();
-
-    macro_rules! test_sort {
-        ($name:expr, $sort:ident) => {
-            println!(
-                "Sorting {} million numbers with {} in Rust ...",
-                len / 1_000_000,
-                $name
-            );
-            let mut data = orig.clone();
-            let start = Instant::now();
-            data.$sort();
-            println!("Time: {:.2?}", start.elapsed());
-            assert!(data.is_sorted());
-        }
-    }
-
-    test_sort!("naive quicksort", qsort);
-    test_sort!("stdlib quicksort", sort_unstable);
-    test_sort!("naive parallel quicksort", par_qsort);
-    test_sort!("Rayon quicksort", par_sort_unstable);
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use quickcheck::quickcheck;
-
-    quickcheck! {
-        fn test_all(d: Vec<i32>) -> bool {
-            let mut d = d;
-
-            let mut expected = d.clone();
-            expected.sort_unstable();
-            d.par_qsort();
-
-            expected == d
-        }
-    }
-}

rust/src/test.scm.txt

@@ -1,8 +0,0 @@
-(define mycount
-  (lambda (x lst)
-      (cond ((null? lst) 0)
-              ((= x (car lst)) (+ 1 (mycount x (cdr lst))))
-            (else (mycount x (cdr lst))))))
-
-;(mycount 5 '((5 2) (2 (4 2) 6) 2))
-(mycount 3 '(1 2 3 4 3 2 3))