default parameters shoudn't be defined more than once

Former-commit-id: be83b57512d3b395243c2963374f7630d87880c2

include/igl/matlab_format.cpp

@@ -5,7 +5,7 @@
 template <typename DerivedM>
 IGL_INLINE const Eigen::WithFormat< DerivedM > igl::matlab_format(
   const Eigen::PlainObjectBase<DerivedM> & M,
-  const std::string name = "")
+  const std::string name)
 {
   using namespace igl;
   using namespace std;
@@ -32,7 +32,7 @@ template <typename DerivedS>
 IGL_INLINE const std::string
 igl::matlab_format(
   const Eigen::SparseMatrix<DerivedS> & S,
-  const std::string name = "")
+  const std::string name)
 {
   using namespace Eigen;
   using namespace igl;