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_ReshapeMat2Mat.cpp b/doc/snippets/Tutorial_ReshapeMat2Mat.cpp
new file mode 100644
index 0000000..f84d6e7
--- /dev/null
+++ b/doc/snippets/Tutorial_ReshapeMat2Mat.cpp
@@ -0,0 +1,6 @@
+MatrixXf M1(2,6);    // Column-major storage
+M1 << 1, 2, 3,  4,  5,  6,
+      7, 8, 9, 10, 11, 12;
+
+Map<MatrixXf> M2(M1.data(), 6,2);
+cout << "M2:" << endl << M2 << endl;
\ No newline at end of file