Merge pull request #2863 from rcurtin/env-static-fix

Move initialization of static environment members into a cpp file.

src/mlpack/methods/reinforcement_learning/environment/CMakeLists.txt

@@ -2,6 +2,7 @@
 # Anything not in this list will not be compiled into mlpack.
 set(SOURCES
   env_type.hpp
+  env_type.cpp
   mountain_car.hpp
   cart_pole.hpp
   continuous_mountain_car.hpp

src/mlpack/methods/reinforcement_learning/environment/env_type.cpp

@@ -0,0 +1,27 @@
+/**
+ * @file methods/reinforcement_learning/environment/env_type.cpp
+ * @author Nishant Kumar
+ *
+ * This file defines the static variables used by the discrete and continuous
+ * environments.
+ *
+ * mlpack is free software; you may redistribute it and/or modify it under the
+ * terms of the 3-clause BSD license.  You should have received a copy of the
+ * 3-clause BSD license along with mlpack.  If not, see
+ * http://www.opensource.org/licenses/BSD-3-Clause for more information.
+ */
+#include "env_type.hpp"
+
+namespace mlpack {
+namespace rl {
+
+// Instantiate static members.
+
+size_t DiscreteActionEnv::State::dimension = 0;
+size_t DiscreteActionEnv::Action::size = 0;
+
+size_t ContinuousActionEnv::State::dimension = 0;
+size_t ContinuousActionEnv::Action::size = 0;
+
+} // namespace rl
+} // namespace mlpack

src/mlpack/methods/reinforcement_learning/environment/env_type.hpp

@@ -105,8 +105,6 @@ class DiscreteActionEnv
    */
   bool IsTerminal(const State& /* state */) const { return false; }
 };
-size_t DiscreteActionEnv::State::dimension = 0;
-size_t DiscreteActionEnv::Action::size = 0;
 
 /**
  * To use the dummy environment, one may start by specifying the state and
@@ -201,8 +199,6 @@ class ContinuousActionEnv
    */
   bool IsTerminal(const State& /* state */) const { return false; }
 };
-size_t ContinuousActionEnv::State::dimension = 0;
-size_t ContinuousActionEnv::Action::size = 0;
 
 } // namespace rl
 } // namespace mlpack