Squashed 'third_party/eigen/' changes from 61d72f6..cf794d3
Change-Id: I9b814151b01f49af6337a8605d0c42a3a1ed4c72
git-subtree-dir: third_party/eigen
git-subtree-split: cf794d3b741a6278df169e58461f8529f43bce5d
diff --git a/doc/snippets/Triangular_solve.cpp b/doc/snippets/Triangular_solve.cpp
new file mode 100644
index 0000000..5484424
--- /dev/null
+++ b/doc/snippets/Triangular_solve.cpp
@@ -0,0 +1,11 @@
+Matrix3d m = Matrix3d::Zero();
+m.triangularView<Eigen::Upper>().setOnes();
+cout << "Here is the matrix m:\n" << m << endl;
+Matrix3d n = Matrix3d::Ones();
+n.triangularView<Eigen::Lower>() *= 2;
+cout << "Here is the matrix n:\n" << n << endl;
+cout << "And now here is m.inverse()*n, taking advantage of the fact that"
+ " m is upper-triangular:\n"
+ << m.triangularView<Eigen::Upper>().solve(n) << endl;
+cout << "And this is n*m.inverse():\n"
+ << m.triangularView<Eigen::Upper>().solve<Eigen::OnTheRight>(n);