Replaces the double-loop in step-3 results extension with just one loop

In step-3, replaces make_grid_and_dofs with just make_grid

In Step-3, removes reference to .gnuplot in subsection title in extensions (results)

In step-3, minor wording change to convey that the suggested boundary condition code is only slightly longer than before

trying to address a comment on indentation by reviewer of PR

adding a blank statement after the 'if' line to address reviewer's clarification

removes the extra line added in prev commit. Also, changes indentation of the loop code to 2 spaces

As per the request of a reviewer, reverts the change made to a sub-heading wherein the .gnuplot was removed

diff --git a/examples/step-3/doc/results.dox b/examples/step-3/doc/results.dox
index 4b6d2a2e3f1a362de6d4fcfa70afb5915f175315..1fe4d9547c516515be8fc8cc97731374165fd1ce 100644 (file)
--- a/examples/step-3/doc/results.dox
+++ b/examples/step-3/doc/results.dox
@@ -120,15 +120,12 @@ suggestions:
   (here 1e-12) of -1 and 1. Try this immediately after calling
   GridGenerator::hyper_cube(), as before:
   @code
-  for (const auto &cell : dof_handler.active_cell_iterators())
-    {
-        for (auto &face : cell->face_iterators())
-          if ((std::fabs(face->center()(1) - (-1.0)) < 1e-12) ||
-              (std::fabs(face->center()(1) - (1.0)) < 1e-12))
-            face->set_boundary_id(1);
-    }
+  for (auto &face : triangulation.active_face_iterators())
+    if (std::fabs(face->center()(1) - (-1.0)) < 1e-12 || 
+        std::fabs(face->center()(1) - (1.0)) < 1e-12)
+      face->set_boundary_id(1);
   @endcode
-  Although this code is significantly longer than before, it is useful for
+  Although this code is a bit longer than before, it is useful for
   complex geometries, as it does not require knowledge of face labels.
 
   <li>
@@ -155,7 +152,7 @@ suggestions:
   already here. For example, we could evaluate the value of the solution in a
   single point and compare the value for different %numbers of global
   refinement (the number of global refinement steps is set in
-  <code>LaplaceProblem::make_grid_and_dofs</code> above). To evaluate the
+  <code>LaplaceProblem::make_grid</code> above). To evaluate the
   solution at a point, say at $(\frac 13, \frac 13)$, we could add the
   following code to the <code>LaplaceProblem::output_results</code> function:
   @code