规范模块目录和第三方依赖结构

third_party/eigen3/doc/examples/class_CwiseBinaryOp.cpp

@@ -0,0 +1,18 @@
+#include <Eigen/Core>
+#include <iostream>
+using namespace Eigen;
+using namespace std;
+
+// define a custom template binary functor
+template<typename Scalar> struct MakeComplexOp {
+  EIGEN_EMPTY_STRUCT_CTOR(MakeComplexOp)
+  typedef complex<Scalar> result_type;
+  complex<Scalar> operator()(const Scalar& a, const Scalar& b) const { return complex<Scalar>(a,b); }
+};
+
+int main(int, char**)
+{
+  Matrix4d m1 = Matrix4d::Random(), m2 = Matrix4d::Random();
+  cout << m1.binaryExpr(m2, MakeComplexOp<double>()) << endl;
+  return 0;
+}