Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/hessian.h

@@ -0,0 +1,47 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+//
+// Copyright (C) 2017 Alec Jacobson <alecjacobson@gmail.com>
+//  and Oded Stein <oded.stein@columbia.edu>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public License
+// v. 2.0. If a copy of the MPL was not distributed with this file, You can
+// obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef IGL_FEM_HESSIAN_H
+#define IGL_FEM_HESSIAN_H
+#include "igl_inline.h"
+
+#include <Eigen/Dense>
+#include <Eigen/Sparse>
+
+
+namespace igl
+{
+    // Constructs the finite element Hessian matrix
+    // as described in https://arxiv.org/abs/1707.04348,
+    // Natural Boundary Conditions for Smoothing in Geometry Processing
+    // (Oded Stein, Eitan Grinspun, Max Wardetzky, Alec Jacobson)
+    // The interior vertices are NOT set to zero yet.
+    //
+    // Inputs:
+    //   V  #V by dim list of mesh vertex positions
+    //   F  #F by 3 list of mesh faces (must be triangles)
+    // Outputs:
+    //   H  #V by #V Hessian energy matrix, each column i
+    //     corresponding to V(i,:)
+    //
+    //
+    //
+    template <typename DerivedV, typename DerivedF, typename Scalar>
+    IGL_INLINE void hessian(
+                            const Eigen::MatrixBase<DerivedV> & V,
+                            const Eigen::MatrixBase<DerivedF> & F,
+                            Eigen::SparseMatrix<Scalar>& H);
+    
+}
+
+#ifndef IGL_STATIC_LIBRARY
+#  include "hessian.cpp"
+#endif
+
+#endif