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/Tutorial_SlicingVec.cpp b/doc/snippets/Tutorial_SlicingVec.cpp
new file mode 100644
index 0000000..07e10bf
--- /dev/null
+++ b/doc/snippets/Tutorial_SlicingVec.cpp
@@ -0,0 +1,4 @@
+RowVectorXf v = RowVectorXf::LinSpaced(20,0,19);
+cout << "Input:" << endl << v << endl;
+Map<RowVectorXf,0,InnerStride<2> > v2(v.data(), v.size()/2);
+cout << "Even:" << v2 << endl;
\ No newline at end of file