RealSchur: Make sure zeros are really zero (cont'd); add default ctor, docs.
diff --git a/doc/snippets/RealSchur_compute.cpp b/doc/snippets/RealSchur_compute.cpp
new file mode 100644
index 0000000..4dcfaf0
--- /dev/null
+++ b/doc/snippets/RealSchur_compute.cpp
@@ -0,0 +1,6 @@
+MatrixXf A = MatrixXf::Random(4,4);
+RealSchur<MatrixXf> schur(4);
+schur.compute(A);
+cout << "The matrix T in the decomposition of A is:" << endl << schur.matrixT() << endl;
+schur.compute(A.inverse());
+cout << "The matrix T in the decomposition of A^(-1) is:" << endl << schur.matrixT() << endl;