diff --git a/cpu-opt/main.cpp b/cpu-opt/main.cpp
index 35d18c2..a55e4ca 100644
--- a/cpu-opt/main.cpp
+++ b/cpu-opt/main.cpp
@@ -273,7 +273,7 @@ int add_coset(const Coxeter &cox,
 /**
  * learn until it can't
  */
-void learn(const Coxeter &cox, CosetTable &cosets,
+inline void learn(const Coxeter &cox, CosetTable &cosets,
     std::vector<RelTable> &reltables) {
 
     const int nrels = cox.nrels;