diff --git a/experimental/AcousticSolverTest.hpp b/experimental/AcousticSolverTest.hpp
index 8c6f09d6d26f0226b9c72f6366502e0e500e5b64..cd6ba4b64dd1372d07095a306aa2ccb40e03a637 100644
--- a/experimental/AcousticSolverTest.hpp
+++ b/experimental/AcousticSolverTest.hpp
@@ -68,8 +68,8 @@ private:
 
   struct ReduceMin;
 
-  const long int m_nj;
-  const long int m_nr;
+  const size_t m_nj;
+  const size_t m_nr;
 
   Kokkos::View<double*> m_br;
   Kokkos::View<double*[2]> m_Ajr;