From a9e2f2e5b968a2dfef9e0942f2220a1383982b5e Mon Sep 17 00:00:00 2001 From: wolf Date: Wed, 25 May 2005 19:23:19 +0000 Subject: [PATCH] Write text. git-svn-id: https://svn.dealii.org/trunk@10752 0785d39b-7218-0410-832d-ea1e28bc413d --- .../step-18.data/results.html | 194 ++++++++++++++++++ 1 file changed, 194 insertions(+) diff --git a/deal.II/doc/tutorial/chapter-2.step-by-step/step-18.data/results.html b/deal.II/doc/tutorial/chapter-2.step-by-step/step-18.data/results.html index 747bdbbb3d..caee2fbee2 100644 --- a/deal.II/doc/tutorial/chapter-2.step-by-step/step-18.data/results.html +++ b/deal.II/doc/tutorial/chapter-2.step-by-step/step-18.data/results.html @@ -1,3 +1,197 @@

Results

+

+Running the program takes a good while if one doesn't change the flags +in the Makefile: in debug mode (the default) and on only a single +machine, it takes about 3h45min on my Athlon XP 2GHz. Fortunately, but +setting debug-mode = off in the Makefile, this can be +reduced significantly, to about 23 minutes, a much more reasonable time. + +

+ +

+If run, the program prints the following output, explaining what it is +doing all that time: + +

+examples/step-18> time make run
+============================ Running step-18
+Timestep 1 at time 1
+  Cycle 0:
+    Number of active cells:       3712 (by partition: 3712)
+    Number of degrees of freedom: 17226 (by partition: 17226)
+    Assembling system... norm of rhs is 2.34224e+10
+    Solver converged in 117 iterations.
+    Updating quadrature point data...
+  Cycle 1:
+    Number of active cells:       12812 (by partition: 12812)
+    Number of degrees of freedom: 51726 (by partition: 51726)
+    Assembling system... norm of rhs is 2.34227e+10
+    Solver converged in 130 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 2 at time 2
+    Assembling system... norm of rhs is 2.30852e+10
+    Solver converged in 131 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 3 at time 3
+    Assembling system... norm of rhs is 2.27792e+10
+    Solver converged in 126 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 4 at time 4
+    Assembling system... norm of rhs is 2.25107e+10
+    Solver converged in 124 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 5 at time 5
+    Assembling system... norm of rhs is 2.22883e+10
+    Solver converged in 122 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 6 at time 6
+    Assembling system... norm of rhs is 2.21272e+10
+    Solver converged in 118 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 7 at time 7
+    Assembling system... norm of rhs is 2.20652e+10
+    Solver converged in 117 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 8 at time 8
+    Assembling system... norm of rhs is 2.22501e+10
+    Solver converged in 127 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 9 at time 9
+    Assembling system... norm of rhs is 2.32742e+10
+    Solver converged in 144 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+Timestep 10 at time 10
+    Assembling system... norm of rhs is 2.55929e+10
+    Solver converged in 149 iterations.
+    Updating quadrature point data...
+    Moving mesh...
+
+ +In other words, it is computing on 12,000 cells and with some 52,000 +unknowns. Not a whole lot, but enough for a coupled three-dimensional +problem to keep a computer busy for a while. At the end of the day, +this is what we have for output: + +
+examples/step-18> ls -l *.d2
+-rw-r--r--  1 bangerth wheeler 8797414 May 25 09:10 solution-0001.0000.d2
+-rw-r--r--  1 bangerth wheeler 8788500 May 25 09:32 solution-0002.0000.d2
+-rw-r--r--  1 bangerth wheeler 8763718 May 25 09:55 solution-0003.0000.d2
+-rw-r--r--  1 bangerth wheeler 8738940 May 25 10:17 solution-0004.0000.d2
+-rw-r--r--  1 bangerth wheeler 8710104 May 25 10:39 solution-0005.0000.d2
+-rw-r--r--  1 bangerth wheeler 8685388 May 25 11:01 solution-0006.0000.d2
+-rw-r--r--  1 bangerth wheeler 8649088 May 25 11:23 solution-0007.0000.d2
+-rw-r--r--  1 bangerth wheeler 8585146 May 25 11:45 solution-0008.0000.d2
+-rw-r--r--  1 bangerth wheeler 8489764 May 25 12:07 solution-0009.0000.d2
+-rw-r--r--  1 bangerth wheeler 8405388 May 25 12:29 solution-0010.0000.d2
+
+
+

+ +

+Let us convert these files in deal.II intermediate format to gmv +format (this assumes that you have already compiled the step-19 +example program): + +

+examples/step-18> ../step-19/step-19
+
+Converter from deal.II intermediate format to other graphics formats.
+
+Usage: ./step-19 [-p parameter_file] list_of_input_files [-x output_format] output_file
+
+examples/step-18> ../step-19/step-19 solution-0001.0000.d2 solution-0001.0000.gmv
+[...]
+
+ +Of course, since we have run the program only in sequential mode, we +do have only one intermediate file for each time step that we have to +take as input. +

+ +

+If we visualize these files with GMV, we get to see the full picture +of the disaster our forced compression wreaks on the cylinder (click +on the images for a larger version; colors in the images encode the +norm of the stress in the material): +

+ + + + + + + + + + + + + + + + + +
+ + + Time = 2 + + + + Time = 5 + + + + Time = 7 +
+ + + Time = 8 + + + + Time = 9 + + + + Time = 10 +
+ +

+As is clearly visible, as we keep compressing the cylinder, it starts +to buckle and ultimately collapses. Towards the end of the simulation, +the deflection pattern becomes nonsymmetric (the cylinder top slides +to the right). The model clearly does not provide for this (all our +forces and boundary deflections are symmetric) but the effect is +probably physically correct anyway: in reality, small inhomogeneities +in the body's material properties would lead it to buckle to one side +to evade the forcing; in numerical simulation, small perturbations +such as numerical round-off or an inexact solution of a linear system +by an iterative solver could have the same effect. \ No newline at end of file -- 2.39.5