规范模块目录和第三方依赖结构

third_party/eigen3/doc/snippets/ComplexSchur_matrixU.cpp

@@ -0,0 +1,4 @@
+MatrixXcf A = MatrixXcf::Random(4,4);
+cout << "Here is a random 4x4 matrix, A:" << endl << A << endl << endl;
+ComplexSchur<MatrixXcf> schurOfA(A);
+cout << "The unitary matrix U is:" << endl << schurOfA.matrixU() << endl;