Use f64 instead.

src/factor_graph.rs

@@ -113,7 +113,7 @@ pub struct LikelihoodFactor {
     id: usize,
     mean: VariableId,
     value: VariableId,
-    variance: f32,
+    variance: f64,
 }
 
 impl LikelihoodFactor {
@@ -122,7 +122,7 @@ impl LikelihoodFactor {
         id: usize,
         mean: VariableId,
         value: VariableId,
-        variance: f32,
+        variance: f64,
     ) -> LikelihoodFactor {
         if let Some(variable) = variable_arena.get_mut(mean) {
             variable.attach_factor(id);
@@ -183,7 +183,7 @@ pub struct SumFactor {
     id: usize,
     sum: VariableId,
     terms: Vec<VariableId>,
-    coeffs: Vec<f32>,
+    coeffs: Vec<f64>,
 }
 
 impl SumFactor {
@@ -192,7 +192,7 @@ impl SumFactor {
         id: usize,
         sum: VariableId,
         terms: Vec<VariableId>,
-        coeffs: Vec<f32>,
+        coeffs: Vec<f64>,
     ) -> SumFactor {
         if let Some(variable) = variable_arena.get_mut(sum) {
             variable.attach_factor(id);
@@ -218,7 +218,7 @@ impl SumFactor {
         variable: VariableId,
         y: Vec<Gaussian>,
         fy: Vec<Gaussian>,
-        a: &Vec<f32>,
+        a: &Vec<f64>,
     ) {
         let size = a.len();
 
@@ -313,21 +313,21 @@ impl SumFactor {
     }
 }
 
-fn v_win(t: f32, e: f32) -> f32 {
+fn v_win(t: f64, e: f64) -> f64 {
     math::pdf(t - e) / math::cdf(t - e)
 }
 
-fn w_win(t: f32, e: f32) -> f32 {
+fn w_win(t: f64, e: f64) -> f64 {
     let vwin = v_win(t, e);
 
     vwin * (vwin + t - e)
 }
 
-fn v_draw(t: f32, e: f32) -> f32 {
+fn v_draw(t: f64, e: f64) -> f64 {
     (math::pdf(-e - t) - math::pdf(e - t)) / (math::cdf(e - t) - math::cdf(-e - t))
 }
 
-fn w_draw(t: f32, e: f32) -> f32 {
+fn w_draw(t: f64, e: f64) -> f64 {
     let vdraw = v_draw(t, e);
     let n = (vdraw * vdraw) + ((e - t) * math::pdf(e - t) + (e + t) * math::pdf(e + t));
     let d = math::cdf(e - t) - math::cdf(-e - t);
@@ -338,7 +338,7 @@ fn w_draw(t: f32, e: f32) -> f32 {
 pub struct TruncateFactor {
     id: usize,
     variable: VariableId,
-    epsilon: f32,
+    epsilon: f64,
     draw: bool,
 }
 
@@ -347,7 +347,7 @@ impl TruncateFactor {
         variable_arena: &mut VariableArena,
         id: usize,
         variable: VariableId,
-        epsilon: f32,
+        epsilon: f64,
         draw: bool,
     ) -> TruncateFactor {
         if let Some(variable) = variable_arena.get_mut(variable) {

src/gaussian.rs

@@ -2,8 +2,8 @@ use std::ops;
 
 #[derive(Clone, Copy)]
 pub struct Gaussian {
-    pub pi: f32,
+    pub pi: f64,
-    pub tau: f32,
+    pub tau: f64,
 }
 
 impl Gaussian {
@@ -11,17 +11,17 @@ impl Gaussian {
         Gaussian::with_pi_tau(0.0, 0.0)
     }
 
-    pub fn with_pi_tau(pi: f32, tau: f32) -> Gaussian {
+    pub fn with_pi_tau(pi: f64, tau: f64) -> Gaussian {
         Gaussian { pi, tau }
     }
 
-    pub fn with_mu_sigma(mu: f32, sigma: f32) -> Gaussian {
+    pub fn with_mu_sigma(mu: f64, sigma: f64) -> Gaussian {
         let pi = 1.0 / sigma.powi(2);
 
         Gaussian::with_pi_tau(pi, pi * mu)
     }
 
-    pub fn mu(&self) -> f32 {
+    pub fn mu(&self) -> f64 {
         if self.pi == 0.0 {
             0.0
         } else {
@@ -29,7 +29,7 @@ impl Gaussian {
         }
     }
 
-    pub fn sigma(&self) -> f32 {
+    pub fn sigma(&self) -> f64 {
         (1.0 / self.pi).sqrt()
     }
 }

src/lib.rs

@@ -8,27 +8,27 @@ use gaussian::Gaussian;
 use matrix::Matrix;
 
 /// Default initial mean of ratings.
-const MU: f32 = 25.0;
+const MU: f64 = 25.0;
 
 /// Default initial standard deviation of ratings.
-const SIGMA: f32 = MU / 3.0;
+const SIGMA: f64 = MU / 3.0;
 
 ///  Default distance that guarantees about 76% chance of winning.
-const BETA: f32 = SIGMA / 2.0;
+const BETA: f64 = SIGMA / 2.0;
 
 ///  Default dynamic factor.
-const TAU: f32 = SIGMA / 100.0;
+const TAU: f64 = SIGMA / 100.0;
 
 ///  Default draw probability of the game.
-const DRAW_PROBABILITY: f32 = 0.10;
+const DRAW_PROBABILITY: f64 = 0.10;
 
 ///  A basis to check reliability of the result.
-const DELTA: f32 = 0.0001;
+const DELTA: f64 = 0.0001;
 
 #[derive(Debug, PartialEq)]
 pub struct Rating {
-    pub mu: f32,
+    pub mu: f64,
-    pub sigma: f32,
+    pub sigma: f64,
 }
 
 impl Default for Rating {
@@ -191,7 +191,7 @@ fn rate(rating_groups: &[&[Rating]]) {
     }
 }
 
-fn quality(rating_groups: &[&[Rating]]) -> f32 {
+fn quality(rating_groups: &[&[Rating]]) -> f64 {
     let flatten_ratings = rating_groups
         .iter()
         .flat_map(|group| group.iter())

src/math.rs

@@ -1,6 +1,6 @@
-use std::f32;
+use std::f64;
 
-fn erfc(x: f32) -> f32 {
+fn erfc(x: f64) -> f64 {
     let z = x.abs();
     let t = 1.0 / (1.0 + z / 2.0);
     let r = t
@@ -21,10 +21,10 @@ fn erfc(x: f32) -> f32 {
     }
 }
 
-pub fn cdf(x: f32) -> f32 {
+pub fn cdf(x: f64) -> f64 {
-    0.5 * erfc(-x / 2.0f32.sqrt())
+    0.5 * erfc(-x / 2.0f64.sqrt())
 }
 
-pub fn pdf(x: f32) -> f32 {
+pub fn pdf(x: f64) -> f64 {
-    1.0 / (2.0 * f32::consts::PI).sqrt() * (-((x / 1.0).powi(2) / 2.0)).exp()
+    1.0 / (2.0 * f64::consts::PI).sqrt() * (-((x / 1.0).powi(2) / 2.0)).exp()
 }

src/matrix.rs

@@ -1,6 +1,6 @@
 use std::ops;
 
-fn det(m: &[f32], x: usize) -> f32 {
+fn det(m: &[f64], x: usize) -> f64 {
     if x == 1 {
         m[0]
     } else if x == 2 {
@@ -17,7 +17,7 @@ fn det(m: &[f32], x: usize) -> f32 {
                 .map(|(_, v)| *v)
                 .collect::<Vec<_>>();
 
-            d += (-1.0f32).powi(n as i32) * m[n] * det(&ms, x - 1);
+            d += (-1.0f64).powi(n as i32) * m[n] * det(&ms, x - 1);
         }
 
         d
@@ -26,7 +26,7 @@ fn det(m: &[f32], x: usize) -> f32 {
 
 #[derive(Clone, Debug)]
 pub struct Matrix {
-    data: Box<[f32]>,
+    data: Box<[f64]>,
     height: usize,
     width: usize,
 }
@@ -80,7 +80,7 @@ impl Matrix {
         matrix
     }
 
-    pub fn determinant(&self) -> f32 {
+    pub fn determinant(&self) -> f64 {
         debug_assert!(self.width == self.height);
 
         det(&self.data, self.width)
@@ -122,7 +122,7 @@ impl Matrix {
 }
 
 impl ops::Index<(usize, usize)> for Matrix {
-    type Output = f32;
+    type Output = f64;
 
     fn index(&self, pos: (usize, usize)) -> &Self::Output {
         &self.data[(self.width * pos.0) + pos.1]
@@ -135,7 +135,7 @@ impl ops::IndexMut<(usize, usize)> for Matrix {
     }
 }
 
-impl<'a> ops::Mul<&'a Matrix> for f32 {
+impl<'a> ops::Mul<&'a Matrix> for f64 {
     type Output = Matrix;
 
     fn mul(self, rhs: &'a Matrix) -> Matrix {