From 3de276cbaac44c5af971bf62b8dbd05f755a46f4 Mon Sep 17 00:00:00 2001
From: Nathan Vegdahl <cessen@cessen.com>
Date: Wed, 25 Oct 2017 07:11:24 -0700
Subject: [PATCH] Make MIS routines handle infinite importance better.

Handle it like the limit case: as A approaches infinity, the
limit approaches 1.0.  Before this, we were getting NaN values.
This fixes that.
---
 src/mis.rs | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/mis.rs b/src/mis.rs
index 1a92dd5..609be2b 100644
--- a/src/mis.rs
+++ b/src/mis.rs
@@ -1,13 +1,21 @@
 #![allow(dead_code)]
 
 pub fn balance_heuristic(a: f32, b: f32) -> f32 {
-    let mis_fac = a / (a + b);
-    a / mis_fac
+    if a.is_infinite() {
+        a
+    } else {
+        let mis_fac = a / (a + b);
+        a / mis_fac
+    }
 }
 
 pub fn power_heuristic(a: f32, b: f32) -> f32 {
-    let a2 = a * a;
-    let b2 = b * b;
-    let mis_fac = a2 / (a2 + b2);
-    a / mis_fac
+    if a.is_infinite() {
+        a
+    } else {
+        let a2 = a * a;
+        let b2 = b * b;
+        let mis_fac = a2 / (a2 + b2);
+        a / mis_fac
+    }
 }