<a name="Results"></a>
<h1>Results</h1>
+<h3>Output of the program and graphical visualization</h3>
+<h4>2D calculations</h4>
+If we run the program in two dimensions, we get the following output:
+@code
+examples/step-31> make run
+============================ Remaking Makefile.dep
+==============optimized===== step-31.cc
+============================ Linking step-31
+============================ Running step-31
+Refinement cycle 0
+ Number of active cells: 64
+ Number of degrees of freedom: 679 (594+85)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+Refinement cycle 1
+ Number of active cells: 160
+ Number of degrees of freedom: 1683 (1482+201)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+
+Refinement cycle 2
+ Number of active cells: 376
+ Number of degrees of freedom: 3813 (3370+443)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+
+Refinement cycle 3
+ Number of active cells: 880
+ Number of degrees of freedom: 8723 (7722+1001)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+
+Refinement cycle 4
+ Number of active cells: 2008
+ Number of degrees of freedom: 19383 (17186+2197)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+Refinement cycle 5
+ Number of active cells: 4288
+ Number of degrees of freedom: 40855 (36250+4605)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+Refinement cycle 6
+ Number of active cells: 8896
+ Number of degrees of freedom: 83885 (74474+9411)
+ Assembling...
+ Computing preconditioner...
+ Solving... 11 outer CG Schur complement iterations for pressure
+@endcode
+Note that the number of (outer) iterations does not increase as we refine the
+mesh.
+In the images below, we show the grids for the first six steps in the program.
+Note how the grid is refined in regions where the solution rapidly changes: On
+the upper boundary, we have Dirichlet boundary conditions that are -1 in the
+left half of the line and 1 in the right one, so there is an aprupt change at
+x=0. Likewise, there are changes from Dirichlet to Neumann data in the two upper
+corners, so the solution changes there as well.
<TABLE WIDTH="60%" ALIGN="center">
<tr>
@image html step-31.2d.solution.png
-
-
-
-
-Output in 3d:
+<h4>3D calculations</h4>
+The program now run in 3d:
@code
Refinement cycle 0
Number of active cells: 32
Number of degrees of freedom: 1356 (1275+81)
Assembling...
Computing preconditioner...
- Solving...
- 13 CG Schur complement iterations for pressure.
+ Solving... 13 outer CG Schur complement iterations for pressure.
Refinement cycle 1
Number of active cells: 144
Number of degrees of freedom: 5088 (4827+261)
Assembling...
Computing preconditioner...
- Solving...
- 14 CG Schur complement iterations for pressure.
+ Solving... 14 outer CG Schur complement iterations for pressure.
Refinement cycle 2
Number of active cells: 704
Number of degrees of freedom: 22406 (21351+1055)
Assembling...
Computing preconditioner...
- Solving...
- 14 CG Schur complement iterations for pressure.
+ Solving... 14 outer CG Schur complement iterations for pressure.
Refinement cycle 3
Number of active cells: 3168
Number of degrees of freedom: 93176 (89043+4133)
Assembling...
Computing preconditioner...
- Solving...
- 15 CG Schur complement iterations for pressure.
+ Solving... 15 outer CG Schur complement iterations for pressure.
Refinement cycle 4
Number of active cells: 11456
Number of degrees of freedom: 327808 (313659+14149)
Assembling...
Computing preconditioner...
- Solving...
- 15 CG Schur complement iterations for pressure.
+ Solving... 15 outer CG Schur complement iterations for pressure.
Refinement cycle 5
Number of active cells: 45056
Number of degrees of freedom: 1254464 (1201371+53093)
Assembling...
Computing preconditioner...
- Solving...
- 14 CG Schur complement iterations for pressure.
+ Solving... 14 outer CG Schur complement iterations for pressure.
Refinement cycle 6
Number of active cells: 170720
Number of degrees of freedom: 4625150 (4432407+192743)
Assembling...
Computing preconditioner...
- Solving...
- 15 CG Schur complement iterations for pressure.
+ Solving... 15 outer CG Schur complement iterations for pressure.
@endcode
-Note that the number of (outer) iterations does not increase as we refine the
-mesh.
+Note again that the number of iterations does not increase as we refine
+the mesh.
Compute times for each iteration alone: seconds, seconds, 1 minute, 5
minutes, 29 minutes, 3h12, 21h39