bring over phonelibs minus frida-gum and qsml

phonelibs/eigen/unsupported/doc/examples/MatrixPower.cpp

@@ -0,0 +1,16 @@
+#include <unsupported/Eigen/MatrixFunctions>
+#include <iostream>
+
+using namespace Eigen;
+
+int main()
+{
+  const double pi = std::acos(-1.0);
+  Matrix3d A;
+  A << cos(1), -sin(1), 0,
+       sin(1),  cos(1), 0,
+	   0 ,      0 , 1;
+  std::cout << "The matrix A is:\n" << A << "\n\n"
+	       "The matrix power A^(pi/4) is:\n" << A.pow(pi/4) << std::endl;
+  return 0;
+}