Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/slice.h

@@ -0,0 +1,87 @@
+// This file is part of libigl, a simple c++ geometry processing library.
+// 
+// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
+//
+// 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_SLICE_H
+#define IGL_SLICE_H
+#include "igl_inline.h"
+
+#include <Eigen/Sparse>
+namespace igl
+{
+  // Act like the matlab X(row_indices,col_indices) operator, where
+  // row_indices, col_indices are non-negative integer indices.
+  // 
+  // Inputs:
+  //   X  m by n matrix
+  //   R  list of row indices
+  //   C  list of column indices
+  // Output:
+  //   Y  #R by #C matrix
+  //
+  // See also: slice_mask
+  template <
+    typename TX, 
+    typename TY>
+  IGL_INLINE void slice(
+    const Eigen::SparseMatrix<TX>& X,
+    const Eigen::Matrix<int,Eigen::Dynamic,1> & R,
+    const Eigen::Matrix<int,Eigen::Dynamic,1> & C,
+    Eigen::SparseMatrix<TY>& Y);
+  // Wrapper to only slice in one direction
+  //
+  // Inputs:
+  //   dim  dimension to slice in 1 or 2, dim=1 --> X(R,:), dim=2 --> X(:,R)
+  //
+  // Note: For now this is just a cheap wrapper.
+  template <
+    typename MatX, 
+    typename DerivedR,
+    typename MatY>
+  IGL_INLINE void slice(
+    const MatX& X,
+    const Eigen::DenseBase<DerivedR> & R,
+    const int dim,
+    MatY& Y);
+  template <
+    typename DerivedX, 
+    typename DerivedR, 
+    typename DerivedC, 
+    typename DerivedY>
+  IGL_INLINE void slice(
+    const Eigen::DenseBase<DerivedX> & X,
+    const Eigen::DenseBase<DerivedR> & R,
+    const Eigen::DenseBase<DerivedC> & C,
+    Eigen::PlainObjectBase<DerivedY> & Y);
+
+  template <typename DerivedX, typename DerivedY>
+  IGL_INLINE void slice(
+    const Eigen::DenseBase<DerivedX> & X,
+    const Eigen::Matrix<int,Eigen::Dynamic,1> & R,
+    Eigen::PlainObjectBase<DerivedY> & Y);
+  // VectorXi Y = slice(X,R);
+  //
+  // This templating is bad because the return type might not have the same
+  // size as `DerivedX`. This will probably only work if DerivedX has Dynamic
+  // as it's non-trivial sizes or if the number of rows in R happens to equal
+  // the number of rows in `DerivedX`.
+  template <typename DerivedX>
+  IGL_INLINE DerivedX slice(
+    const Eigen::DenseBase<DerivedX> & X,
+    const Eigen::Matrix<int,Eigen::Dynamic,1> & R);
+  template <typename DerivedX>
+  IGL_INLINE DerivedX slice(
+    const Eigen::DenseBase<DerivedX>& X,
+    const Eigen::Matrix<int,Eigen::Dynamic,1> & R,
+    const int dim);
+
+}
+
+#ifndef IGL_STATIC_LIBRARY
+#  include "slice.cpp"
+#endif
+
+#endif