When we run the program, the following is printed on screen:
@verbatim
+DEAL::
+DEAL::Parsing parameter file parameters.prm
+DEAL::for a 2 dimensional simulation.
DEAL:GMRES::Starting value 2.21576
-DEAL:GMRES::Convergence step 1 value 2.41954e-13
+DEAL:GMRES::Convergence step 1 value 2.37635e-13
DEAL::Cycle 0:
DEAL:: Number of active cells: 20
DEAL:: Number of degrees of freedom: 20
DEAL:GMRES::Starting value 3.15543
-DEAL:GMRES::Convergence step 1 value 2.90310e-13
+DEAL:GMRES::Convergence step 1 value 2.89310e-13
DEAL::Cycle 1:
DEAL:: Number of active cells: 40
DEAL:: Number of degrees of freedom: 40
DEAL:GMRES::Starting value 4.46977
-DEAL:GMRES::Convergence step 1 value 3.11950e-13
+DEAL:GMRES::Convergence step 1 value 3.11815e-13
DEAL::Cycle 2:
DEAL:: Number of active cells: 80
DEAL:: Number of degrees of freedom: 80
DEAL:GMRES::Starting value 6.32373
-DEAL:GMRES::Convergence step 1 value 3.22659e-13
+DEAL:GMRES::Convergence step 1 value 3.22474e-13
DEAL::Cycle 3:
DEAL:: Number of active cells: 160
DEAL:: Number of degrees of freedom: 160
DEAL::
cycle cells dofs L2(phi) Linfty(alpha)
- 0 20 20 1.149e-07 - 5.000e-02 -
- 1 40 40 4.330e-08 1.41 2.500e-02 1.00
- 2 80 80 1.848e-08 1.23 1.250e-02 1.00
- 3 160 160 8.798e-09 1.07 6.250e-03 1.00
+ 0 20 20 4.465e-02 - 5.000e-02 -
+ 1 40 40 1.081e-02 2.05 2.500e-02 1.00
+ 2 80 80 2.644e-03 2.03 1.250e-02 1.00
+ 3 160 160 6.529e-04 2.02 6.250e-03 1.00
DEAL::
DEAL::Parsing parameter file parameters.prm
DEAL::for a 3 dimensional simulation.
-DEAL:GMRES::Starting value 1.42333
-DEAL:GMRES::Convergence step 3 value 7.74202e-17
+DEAL:GMRES::Starting value 2.84666
+DEAL:GMRES::Convergence step 3 value 8.68638e-18
DEAL::Cycle 0:
DEAL:: Number of active cells: 24
DEAL:: Number of degrees of freedom: 26
-DEAL:GMRES::Starting value 3.17144
-DEAL:GMRES::Convergence step 5 value 8.31039e-11
+DEAL:GMRES::Starting value 6.34288
+DEAL:GMRES::Convergence step 5 value 1.38740e-11
DEAL::Cycle 1:
DEAL:: Number of active cells: 96
DEAL:: Number of degrees of freedom: 98
-DEAL:GMRES::Starting value 6.48898
-DEAL:GMRES::Convergence step 5 value 8.89146e-11
+DEAL:GMRES::Starting value 12.9780
+DEAL:GMRES::Convergence step 5 value 3.29225e-11
DEAL::Cycle 2:
DEAL:: Number of active cells: 384
DEAL:: Number of degrees of freedom: 386
-DEAL:GMRES::Starting value 13.0437
-DEAL:GMRES::Convergence step 6 value 3.50193e-12
+DEAL:GMRES::Starting value 26.0874
+DEAL:GMRES::Convergence step 6 value 1.47271e-12
DEAL::Cycle 3:
DEAL:: Number of active cells: 1536
DEAL:: Number of degrees of freedom: 1538
DEAL::
cycle cells dofs L2(phi) Linfty(alpha)
- 0 24 26 3.415e-06 - 2.327e-01 -
- 1 96 98 7.248e-07 2.24 1.239e-01 0.91
- 2 384 386 1.512e-07 2.26 6.319e-02 0.97
- 3 1536 1538 6.576e-08 1.20 3.176e-02 0.99
+ 0 24 26 6.873e-01 - 2.327e-01 -
+ 1 96 98 1.960e-01 1.81 1.239e-01 0.91
+ 2 384 386 4.837e-02 2.02 6.319e-02 0.97
+ 3 1536 1538 1.176e-02 2.04 3.176e-02 0.99
@endverbatim
As we can see from the convergence table in 2d, if we choose