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doc/examples/TutorialLinAlgExSolveLDLT.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+using namespace Eigen;
+
+int main()
+{
+   Matrix2f A, b;
+   A << 2, -1, -1, 3;
+   b << 1, 2, 3, 1;
+   cout << "Here is the matrix A:\n" << A << endl;
+   cout << "Here is the right hand side b:\n" << b << endl;
+   Matrix2f x = A.ldlt().solve(b);
+   cout << "The solution is:\n" << x << endl;
+}