diff --git a/src/demeter/solve.hpp b/src/demeter/solve.hpp
new file mode 100644
index 0000000..3148e4c
--- /dev/null
+++ b/src/demeter/solve.hpp
@@ -0,0 +1,3 @@
+#pragma once
+
+#include "solve/solver.hpp"
\ No newline at end of file
diff --git a/src/demeter/methods.hpp b/src/demeter/solve/methods.hpp
similarity index 100%
rename from src/demeter/methods.hpp
rename to src/demeter/solve/methods.hpp
diff --git a/src/demeter/solve/solver.hpp b/src/demeter/solve/solver.hpp
index cd6e216..eaf686d 100644
--- a/src/demeter/solve/solver.hpp
+++ b/src/demeter/solve/solver.hpp
@@ -2,8 +2,8 @@
 
 #include <Eigen/Core>
 
+#include "methods.hpp"
 #include "demeter/common.hpp"
-#include "demeter/methods.hpp"
 #include "demeter/model/lattice.hpp"
 
 namespace Demeter {
@@ -14,8 +14,8 @@ class Solver {
       : core_(core), am_(am), sm_(sm) {};
   void solve();
 
-  auto getFlux() const { return flux_; }
-  auto getPower() const { return power_; }
+  const auto& getFlux() const { return flux_; }
+  const auto& getPower() const { return power_; }
 
  private:
   const Lattice& core_;