diff --git a/MathLib/LinAlg/Eigen/EigenOption.h b/MathLib/LinAlg/Eigen/EigenOption.h
index 720afeee7ef513d3bb9ad9a7004cdca0f74f1592..814e3d5f56ed165a0fd01e47bf32e0313f5ec9f0 100644
--- a/MathLib/LinAlg/Eigen/EigenOption.h
+++ b/MathLib/LinAlg/Eigen/EigenOption.h
@@ -19,7 +19,7 @@ namespace MathLib
 struct EigenOption final
 {
     /// Solver type
-    enum class SolverType : int
+    enum class SolverType : short
     {
         INVALID,
         CG,
@@ -28,7 +28,7 @@ struct EigenOption final
     };
 
     /// Preconditioner type
-    enum class PreconType : int
+    enum class PreconType : short
     {
         NONE,
         DIAGONAL