Element-by-element techniques and Parallel Programming - The Boundary Element Method with Programming - page 206

minimised output) and have been combined into a single library bem_lib, which also
contains the iterative solution subroutine bicgstab_l . For reasons associated with global
variable names used later in parallelised programs, the number of degrees of freedom
per element, called Ndof in Program 7.1, has been changed to N_dof . In the iterative
algorithm there are variables ell ( INTEGER ) and kappa ( REAL ) which have to be
declared and input, and since the process must be terminated somehow there are
declarations and input of an iteration termination counter its ( INTEGER ) and a
convergence tolerance tol ( REAL ). The only other change is the replacement of the
direct solver solve by the iterative one bicgstab_l ; further, because the sample input file
(although for a “small” problem) takes an example with 600 elements, the output has
been truncated to list only the first and last node, coordinate, element and so on.
Therefore in the output Elements_2 loop the counter increment is maxe-1 rather than 1 .

8.2.1 Sample input file

The example chosen is of a cubical cavern in an infinite elastic medium loaded with a
uniform traction on all 6 faces and meshed by 600 linear elements (see Figure 8.2).
Square excavation 3D
3
3
2
0
1
0.1000E+04
0.0000E+00
602
600
10.000 0.000 0.000
10.000 1.000 0.000
9.000 1.000 0.000
9.000 0.000 0.000
8.000 1.000 0.000
8.000 0.000 0.000
............................
10.000 5.000 9.000
10.000 6.000 9.000
10.000 7.000 9.000
10.000 8.000 9.000
10.000 9.000 9.000
1 2 3 4
4 3 5 6
6 5 7 8
8 7 9 10
10 9 11 12
12 11 13 14
.......................
597 131 133 598