From 89b3f431c087e54441a6e18f435cdd99957d4fba Mon Sep 17 00:00:00 2001
From: "Fabio A. Correa" <facorread@gmail.com>
Date: Wed, 25 Mar 2020 10:11:38 -0400
Subject: [PATCH] Bugfix for panic on WeightedIndex::update_weights

WeightedIndex::update_weights() uses subtraction on old_w. Rounding errors, particularly on f32, may bring total_weight to below 0. This PR makes sure this situation results in an error.
---
 src/distributions/weighted/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/distributions/weighted/mod.rs b/src/distributions/weighted/mod.rs
index 357e3a9f024..91779d66167 100644
--- a/src/distributions/weighted/mod.rs
+++ b/src/distributions/weighted/mod.rs
@@ -183,7 +183,7 @@ impl<X: SampleUniform + PartialOrd> WeightedIndex<X> {
             total_weight += w;
             prev_i = Some(i);
         }
-        if total_weight == zero {
+        if total_weight <= zero {
             return Err(WeightedError::AllWeightsZero);
         }