tutorial/compilation.md

@@ -60,12 +60,22 @@ gmake <mode> -j<#>
 
 -   `<mode>`
 
+Main modes corresponding to the source code in the following
+[Branches](../branches) `master` (`fw`), `master-ad` (`ad`),
+`master-sm` (`sm`).
+
 1.  `fw` (forward mode)
 2.  `sm` (stochastic mode)
 3.  `ad` (inverse mode automatic differentiation)
-4.  `ad` (inverse mode divided differences)
+
+From the source code in branch `master-all`, all of these modes can be
+built.
+
+Specialized compilation modes for inverse computations using the
+source code in branch `master-ad`:
+
+4.  `dd` (inverse mode divided differences)
 5.  `lib_oed` (build code as a library)
-6.  For more information see [Branches](../branches).
 
 -   `<phys>`