]> https://gitweb.dealii.org/ - dealii-svn.git/commitdiff
Doc addition.
authorwolf <wolf@0785d39b-7218-0410-832d-ea1e28bc413d>
Thu, 30 Dec 1999 23:40:16 +0000 (23:40 +0000)
committerwolf <wolf@0785d39b-7218-0410-832d-ea1e28bc413d>
Thu, 30 Dec 1999 23:40:16 +0000 (23:40 +0000)
git-svn-id: https://svn.dealii.org/trunk@2140 0785d39b-7218-0410-832d-ea1e28bc413d

deal.II/deal.II/Attic/examples/step-by-step/step-5/step-5.cc
deal.II/doc/tutorial/chapter-2.step-by-step/step-5.intro
deal.II/examples/step-5/step-5.cc

index e595b4484255361cbb4fffed9c4e3037be752d6f..8e0beba015e888dcf9a2ffbd3f87040fc80bba59 100644 (file)
@@ -837,6 +837,12 @@ void LaplaceProblem<dim>::run ()
                                           // what not to do, after
                                           // all.
          
+                                          // We can now actually read
+                                          // the grid. It is in UCD
+                                          // (unstructured cell data)
+                                          // format, as supported by
+                                          // AVS Explorer, for
+                                          // example:
          ifstream input_file("circle-grid.inp");
          grid_in.read_ucd (input_file);
 
index 1518606e4305295f10522604feacd142c43ef773..362d757e286fa59a3d1c4f04d514cd28eccecaff 100644 (file)
@@ -1,3 +1,37 @@
 <a name="Intro"></a>
 <h1>Introduction</h1>
 
+This example does not show revolutionary new things, but it shows many
+small improvements over the previous examples, and also many small
+things that can usually be found in finite element programs. Among
+them are:
+<ul>
+  <li> Computations on successively refined grids. At least in the
+       mathematical sciences, it is common to compute solutions on
+       a hierarchy of grids, in order to get a fealing of the accuracy
+       of the solution; if you only have one solution on one grid, you
+       usually can't give a guess with respect to the accuracy of the
+       solution. Furthermore, deal.II is designed to support adaptive
+       algorithms where iterative solution on successively refined
+       grids is at the heart of algorithms. Although adaptive grids
+       are not used in this example, the foundations for them is laid
+       here. 
+  <li> In practical applications, the domains are often subdivided
+       into triangulations by automatic mesh generators. In order to
+       use them, it is important to read coarse grids from a file. In
+       this example, we will read a coarse grid in UCD (unstructured
+       cell data) format as used by AVS Explorer.
+  <li> Finite element programs usually use extensive amounts of
+       computing time, so some optimizations are sometimes
+       necessary. We will show some of them in the assemblage of
+       matrices and vectors.
+  <li> On the other side, finite element programs tend to be rather
+       complex, so debugging is an important aspect. We support safe
+       programming by using assertions that check the validity of
+       parameters and internal states in a debug mode, but are removed
+       in optimized mode.
+  <li> Regarding the mathematical side, we show how to support a
+       variable coefficient in the elliptic operator and how to use
+       preconditioned iterative solvers for the linear systems of
+       equations.
+</ul>
index e595b4484255361cbb4fffed9c4e3037be752d6f..8e0beba015e888dcf9a2ffbd3f87040fc80bba59 100644 (file)
@@ -837,6 +837,12 @@ void LaplaceProblem<dim>::run ()
                                           // what not to do, after
                                           // all.
          
+                                          // We can now actually read
+                                          // the grid. It is in UCD
+                                          // (unstructured cell data)
+                                          // format, as supported by
+                                          // AVS Explorer, for
+                                          // example:
          ifstream input_file("circle-grid.inp");
          grid_in.read_ucd (input_file);
 

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