Merged branch 'dev_native' into lm_sla_supports_auto

Added igl library files

src/igl/redux.h

@@ -0,0 +1,70 @@
+#ifndef IGL_REDUX_H
+#define IGL_REDUX_H
+#include <Eigen/Core>
+#include <Eigen/Sparse>
+namespace igl
+{
+  // REDUX Perform reductions on the rows or columns of a SparseMatrix. This is
+  // _similar_ to DenseBase::redux, but different in two important ways:
+  //  1. (unstored) Zeros are **not** "visited", however if the first element
+  //     in the column/row  does not appear in the first row/column then the
+  //     reduction is assumed to start with zero. In this way, "any", "all",
+  //     "count"(non-zeros) work as expected. This means it is **not** possible
+  //     to use this to count (implicit) zeros.
+  //  2. This redux is more powerful in the sense that A and B may have
+  //     different types. This makes it possible to count the number of
+  //     non-zeros in a SparseMatrix<bool> A into a VectorXi B.
+  //
+  // Inputs:
+  //   A  m by n sparse matrix
+  //   dim  dimension along which to sum (1 or 2)
+  //   func  function handle with the prototype `X(Y a, I i, J j, Z b)` where a
+  //     is the running value, b is A(i,j)
+  // Output:
+  //   S  n-long sparse vector (if dim == 1) 
+  //   or
+  //   S  m-long sparse vector (if dim == 2)
+  template <typename AType, typename Func, typename DerivedB>
+  inline void redux(
+    const Eigen::SparseMatrix<AType> & A,
+    const int dim,
+    const Func & func,
+    Eigen::PlainObjectBase<DerivedB> & B);
+}
+
+// Implementation
+
+#include "redux.h"
+#include "for_each.h"
+
+template <typename AType, typename Func, typename DerivedB>
+inline void igl::redux(
+  const Eigen::SparseMatrix<AType> & A,
+  const int dim,
+  const Func & func,
+  Eigen::PlainObjectBase<DerivedB> & B)
+{
+  assert((dim == 1 || dim == 2) && "dim must be 2 or 1");
+  // Get size of input
+  int m = A.rows();
+  int n = A.cols();
+  // resize output
+  B = DerivedB::Zero(dim==1?n:m);
+  const auto func_wrap = [&func,&B,&dim](const int i, const int j, const int v)
+  {
+    if(dim == 1)
+    {
+      B(j) = i == 0? v : func(B(j),v);
+    }else
+    {
+      B(i) = j == 0? v : func(B(i),v);
+    }
+  };
+  for_each(A,func_wrap);
+}
+
+
+//#ifndef IGL_STATIC_LIBRARY
+//#  include "redux.cpp"
+//#endif
+#endif