fix template to match explicits

Former-commit-id: f34f8481f5b30514c5ec1f363eabcc4a06c0ab6a

include/igl/point_simplex_squared_distance.cpp

@@ -147,7 +147,7 @@ IGL_INLINE void igl::point_simplex_squared_distance(
   const Eigen::MatrixBase<DerivedEle> & Ele,
   const typename DerivedEle::Index primitive,
   Derivedsqr_d & sqr_d,
-  Eigen::PlainObjectBase<Derivedc> & c)
+  Eigen::MatrixBase<Derivedc> & c)
 {
   // Use Dynamic because we don't know Ele.cols() at compile time.
   Eigen::Matrix<typename Derivedc::Scalar,1,Eigen::Dynamic> b;

include/igl/point_simplex_squared_distance.h

@@ -35,7 +35,7 @@ namespace igl
     const Eigen::MatrixBase<DerivedEle> & Ele,
     const typename DerivedEle::Index i,
     Derivedsqr_d & sqr_d,
-    Eigen::PlainObjectBase<Derivedc> & c);
+    Eigen::MatrixBase<Derivedc> & c);
   // Determine squared distance from a point to linear simplex.
   // Also return barycentric coordinate of closest point. 
   //