From 7ad47d330f1438edd07fc25855e57b5ae6624431 Mon Sep 17 00:00:00 2001
From: Anders Olsson <anders.e.olsson@gmail.com>
Date: Wed, 2 Jan 2019 22:24:42 +0100
Subject: [PATCH] More clippy fixes.

---
 src/factor_graph.rs | 12 +++++-----
 src/lib.rs          |  4 +++-
 src/math.rs         | 53 +++++++++++++++++++++++----------------------
 3 files changed, 36 insertions(+), 33 deletions(-)

diff --git a/src/factor_graph.rs b/src/factor_graph.rs
index 5090f2b..57663ef 100644
--- a/src/factor_graph.rs
+++ b/src/factor_graph.rs
@@ -232,8 +232,8 @@ impl SumFactor {
         &self,
         variable_arena: &mut VariableArena,
         variable: VariableId,
-        y: Vec<Gaussian>,
-        fy: Vec<Gaussian>,
+        y: &[Gaussian],
+        fy: &[Gaussian],
         a: &[f64],
     ) {
         let (sum_pi, sum_tau) =
@@ -263,7 +263,7 @@ impl SumFactor {
     }
 
     pub fn update_sum(&self, variable_arena: &mut VariableArena) {
-        let (y, fy) = self
+        let (y, fy): (Vec<_>, Vec<_>) = self
             .terms
             .iter()
             .map(|term| {
@@ -273,7 +273,7 @@ impl SumFactor {
             })
             .unzip();
 
-        self.internal_update(variable_arena, self.sum, y, fy, &self.coeffs);
+        self.internal_update(variable_arena, self.sum, &y, &fy, &self.coeffs);
     }
 
     pub fn update_term(&self, variable_arena: &mut VariableArena, index: usize) {
@@ -293,7 +293,7 @@ impl SumFactor {
             })
             .collect::<Vec<_>>();
 
-        let (y, fy) = self
+        let (y, fy): (Vec<_>, Vec<_>) = self
             .terms
             .iter()
             .enumerate()
@@ -305,7 +305,7 @@ impl SumFactor {
             })
             .unzip();
 
-        self.internal_update(variable_arena, idx_term, y, fy, &a);
+        self.internal_update(variable_arena, idx_term, &y, &fy, &a);
     }
 
     pub fn update_all_terms(&self, variable_arena: &mut VariableArena) {
diff --git a/src/lib.rs b/src/lib.rs
index 31ed10d..c457bca 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,5 @@
+#![allow(clippy::unreadable_literal, clippy::excessive_precision)]
+
 mod factor_graph;
 mod gaussian;
 mod math;
@@ -421,7 +423,7 @@ mod tests {
 
         assert_relative_eq!(
             ts.quality(&[&[alice], &[bob]]),
-            0.4472135954999579,
+            0.447_213_595_499_957_9,
             epsilon = EPSILON
         );
     }
diff --git a/src/math.rs b/src/math.rs
index 469ef60..6a2d540 100644
--- a/src/math.rs
+++ b/src/math.rs
@@ -1,5 +1,3 @@
-#![allow(clippy::unreadable_literal, clippy::excessive_precision)]
-
 use statrs::distribution::{Continuous, Normal, Univariate};
 
 const S2PI: f64 = 2.50662827463100050242_e0;
@@ -70,44 +68,33 @@ const Q2: [f64; 8] = [
 ];
 
 fn polevl(x: f64, coef: &[f64], n: usize) -> f64 {
-    let mut ans = coef[0];
-
-    for i in 1..n + 1 {
-        ans = ans * x + coef[i];
-    }
-
-    ans
+    coef.iter()
+        .skip(1)
+        .take(n)
+        .fold(coef[0], |ans, coef| ans * x + coef)
 }
 
 fn p1evl(x: f64, coef: &[f64], n: usize) -> f64 {
-    let mut ans = x + coef[0];
-
-    for i in 1..n {
-        ans = ans * x + coef[i];
-    }
-
-    ans
+    coef.iter().take(n).fold(1.0, |ans, coef| ans * x + coef)
 }
 
-fn ndtri(y0: f64) -> f64 {
-    let mut y = y0;
-
-    let code = if y > (1.0 - 0.13533528323661269189) {
-        y = 1.0 - y;
+fn ndtri(mut y0: f64) -> f64 {
+    let code = if y0 > (1.0 - 0.13533528323661269189) {
+        y0 = 1.0 - y0;
 
         false
     } else {
         true
     };
 
-    if y > 0.13533528323661269189 {
-        y -= 0.5;
-        let y2 = y * y;
+    if y0 > 0.13533528323661269189 {
+        y0 -= 0.5;
+        let y1 = y0 * y0;
 
-        return (y + y * (y2 * polevl(y2, &P0, 4) / p1evl(y2, &Q0, 8))) * S2PI;
+        return (y0 + y0 * (y1 * polevl(y1, &P0, 4) / p1evl(y1, &Q0, 8))) * S2PI;
     }
 
-    let x = (-2.0 * y.ln()).sqrt();
+    let x = (-2.0 * y0.ln()).sqrt();
     let z = 1.0 / x;
 
     let x0 = x - x.ln() / x;
@@ -146,4 +133,18 @@ mod tests {
     fn test_cdf() {
         assert_relative_eq!(cdf(0.5), 0.6914624612740131);
     }
+
+    #[test]
+    fn test_polevl() {
+        assert_relative_eq!(polevl(1.0, &P0, 4), -5.946465329663694);
+        assert_relative_eq!(polevl(1.0, &P1, 8), 153.51931825976564);
+        assert_relative_eq!(polevl(1.0, &P2, 8), 15.63898396843608);
+    }
+
+    #[test]
+    fn test_p1evl() {
+        assert_relative_eq!(p1evl(1.0, &Q0, 8), 1.4736150619750965);
+        assert_relative_eq!(p1evl(1.0, &Q1, 8), 120.85394687227081);
+        assert_relative_eq!(p1evl(1.0, &Q2, 8), 12.311115335036716);
+    }
 }