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/MatrixBase_triangularView.cpp b/doc/snippets/MatrixBase_triangularView.cpp
new file mode 100644
index 0000000..03aa303
--- /dev/null
+++ b/doc/snippets/MatrixBase_triangularView.cpp
@@ -0,0 +1,9 @@
+Matrix3i m = Matrix3i::Random();
+cout << "Here is the matrix m:" << endl << m << endl;
+cout << "Here is the upper-triangular matrix extracted from m:" << endl
+     << Matrix3i(m.triangularView<Eigen::Upper>()) << endl;
+cout << "Here is the strictly-upper-triangular matrix extracted from m:" << endl
+     << Matrix3i(m.triangularView<Eigen::StrictlyUpper>()) << endl;
+cout << "Here is the unit-lower-triangular matrix extracted from m:" << endl
+     << Matrix3i(m.triangularView<Eigen::UnitLower>()) << endl;
+// FIXME need to implement output for triangularViews (Bug 885)