Expand "hash table" size by the golden ratio.

Author: abellgithub

include/delaunator.cpp

@@ -305,7 +305,8 @@ Delaunator::Delaunator(std::vector<double> const& in_coords)
             { return dists[i] < dists[j]; });
 
     // initialize a hash table for storing edges of the advancing convex hull
-    m_hash_size = static_cast<std::size_t>(std::ceil(std::sqrt(n)));
+    // 1.618 is the golden ratio.
+    m_hash_size = static_cast<std::size_t>(1.618 * std::ceil(std::sqrt(n)));
     m_hash.resize(m_hash_size);
     std::fill(m_hash.begin(), m_hash.end(), INVALID_INDEX);