From 6e2b5c3d2a301f17669760d5154c04d8f16b26a5 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@gmail.com>
Date: Mon, 29 Mar 2021 19:29:39 +0000
Subject: [PATCH] remove trig.rs (no longer used)

---
 Cargo.toml      |  4 ----
 benches/trig.rs | 16 --------------
 src/lib.rs      |  1 -
 src/trig.rs     | 55 -------------------------------------------------
 4 files changed, 76 deletions(-)
 delete mode 100644 benches/trig.rs
 delete mode 100644 src/trig.rs

diff --git a/Cargo.toml b/Cargo.toml
index 9dfdc2a..9317f8d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,10 +19,6 @@ criterion = "0.3.4"
 [patch.crates-io]
 rayon = {git = "https://github.com/rayon-rs/rayon.git"} #for using git version of rayon
 
-[[bench]]
-name = "trig"
-harness = false
-
 [profile.dev]
 codegen-units = 1
 opt-level = 3
diff --git a/benches/trig.rs b/benches/trig.rs
deleted file mode 100644
index 2537d3a..0000000
--- a/benches/trig.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-use physarum::trig;
-
-use criterion::{black_box, criterion_group, criterion_main, Criterion};
-
-fn bench_cos_appr(c: &mut Criterion) {
-    c.bench_function("Approximate cosine", |b| {
-        b.iter(|| trig::cos(black_box(1.0)))
-    });
-}
-
-fn bench_cos_exact(c: &mut Criterion) {
-    c.bench_function("Exact cosine", |b| b.iter(|| f32::cos(black_box(1.0))));
-}
-
-criterion_group!(benches, bench_cos_appr, bench_cos_exact);
-criterion_main!(benches);
diff --git a/src/lib.rs b/src/lib.rs
index c743b7b..4709868 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,6 +2,5 @@ mod blur;
 mod grid;
 pub mod model;
 mod palette;
-pub mod trig; // for benchmarking
 mod util;
 mod imgdata; // for storing image data
\ No newline at end of file
diff --git a/src/trig.rs b/src/trig.rs
deleted file mode 100644
index eb5046a..0000000
--- a/src/trig.rs
+++ /dev/null
@@ -1,55 +0,0 @@
-/// From https://bits.stephan-brumme.com/absFloat.html
-#[inline(always)]
-fn abs(x: f32) -> f32 {
-    f32::from_bits(x.to_bits() & 0x7FFF_FFFF)
-}
-
-/// Branchless floor implementation
-#[inline(always)]
-fn floor(x: f32) -> f32 {
-    let mut x_trunc = (x as i32) as f32;
-    x_trunc -= (x < x_trunc) as i32 as f32;
-    x_trunc
-}
-
-/// Approximates `cos(x)` in radians with the maximum error of `0.002`
-/// https://stackoverflow.com/posts/28050328/revisions
-pub fn cos(mut x: f32) -> f32 {
-    const ALPHA: f32 = 0.5 * std::f32::consts::FRAC_1_PI;
-    x *= ALPHA;
-    x -= 0.25_f32 + floor(x + 0.25_f32);
-    x *= 16.0_f32 * (abs(x) - 0.5_f32);
-    x += 0.225_f32 * x * (abs(x) - 1.0_f32);
-    x
-}
-
-/// Approximates `sin(x)` in radians with the maximum error of `0.002`
-pub fn sin(x: f32) -> f32 {
-    cos(x - std::f32::consts::FRAC_PI_2)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use itertools::repeat_n;
-
-    #[test]
-    fn test_cos() {
-        let n_points = 1000;
-        let x: Vec<f32> = repeat_n(std::f32::consts::TAU / (n_points - 1) as f32, n_points)
-            .enumerate()
-            .map(|(i, delta)| i as f32 * delta)
-            .collect();
-
-        let exact: Vec<f32> = x.iter().map(|v| v.cos()).collect();
-        let appr: Vec<f32> = x.iter().map(|v| cos(*v)).collect();
-
-        let mut max_error = 0.0_f32;
-        for (y_exact, y_appr) in exact.iter().zip(&appr) {
-            max_error = (y_exact - y_appr).abs().max(max_error);
-        }
-
-        // The error bound is even better!
-        assert!(max_error <= 0.0011);
-    }
-}