BES Version 5 - README

Boundary Element System Original version written by Earlin Lutz Cornell University 1991

Parallel version by Ketan Shah Cornell University 1997

Revised serial and parallel versions by Bruce Carter Cornell University 2000

This readme file pertains only to the revised version Version 5 for both serial and parallel versions. 

The current versions no longer require logical links or environment variables to be set, although you should add the directory where you place the executables to your PATH environment variable.

The parallel version is designed to work with MPI and runs on the IBM SP2, RedHat Linux, and under MSWindows 2000/NT. The parallel version under MSWindows requires the MPIPro.dll and mpirun. We will not be supporting anything but MPIPro on the MSWindows platforms (at least at this time).

The serial version contains four executables:
cge_bes.exe -> Gauss elimination in-core
cit_bes.exe -> iterative in-core (various iterative schemes)
cocqr_bes.exe -> QR factorization out-of-core
cocit_bes.exe -> iterative out-of-core (various iterative schemes)

The four executables are packed into a single tar.gz or tgz file on the download page. You can unpack this file with Winzip or with gunzip & tar.

The parallel version has one executable:
cqp_bes.exe

Command line flags are supplied directly to the various executables. For instance:
"cge_bes -help"
will list all the command line flags that can be defined. Normally one needs to only define the input file: "cge_bes -file bes_input.bes"
The parallel version requires mpirun and can be executed as:
"mpirun -np # cqp_bes -file bes_input.bes"
where # defines the number of processors.

BES File Formats

The .bes input format is fairly simple until we get to the elements.  Each
region of the model is a 'domain' and is numbered.  The region properties
are elastic modulus and Poisson's ratio.

cd_region_properties
1 1e+07 0.33

Each node is numbered and then the global Cartesian x y z coordinates given.

cd_define_node
1 0.666667 0 0.666667

Each element is numbered, then the number of nodes followed by the node id's
is given. In the example below, element 1 has 4 nodes.  The second line
defines the element number and then the regions on either side of the
element.  The outside free region is numbered 0 and is given second. The
next few lines define the boundary conditions at each of the nodes of the
element for each axis.  See below for details.

cd_define_element
1 4 1 27 28 2
cd_element_regions
1 1 0
cd_simple_bc
1 1 1 3 0
cd_simple_bc
1 1 2 3 0
cd_simple_bc
1 1 3 3 0
cd_simple_bc
1 4 1 3 0
cd_simple_bc
1 4 2 3 0
cd_simple_bc
1 4 3 3 0
cd_simple_bc
1 3 1 3 0
cd_simple_bc
1 3 2 3 0
cd_simple_bc
1 3 3 3 0
cd_simple_bc
1 2 1 3 0
cd_simple_bc
1 2 2 3 0
cd_simple_bc
1 2 3 3 0

Details:

"cd_simple_bc"
element_id   node_i_in_list  axis_id  bc_code  bc_value

The node_i_in_list will range from 1 to the number of nodes in the element -
in the case above - 1 to 4.  The axis id's are 1,2,3 corresponding to the
gloabal Cartesian x,y,z axes.  The boundary condition code will generally be
3 or 4 or 5.  The code 3 implies the node is fixed with the bc_value
displacement prescribed.  The code 4 implies a traction (again given by
bc_value) at the node.  The code 5 implies the node is fixed but not based
on the current element - at corners of a cube, for example, where we apply
constraint to one surface, but not the adjacent surfaces.  Also, note that
traction values are defined at a node but are distributed over the element.

The file format for the .besout file is similar.

UES     1  4
0 0 0
0 0 0
0 0 0
0 0 0
PES     1  4
 -0.1576563E+02 -0.7511345E+03 -0.1576563E+02
 -0.1158768E+02 -0.1145763E+04  0.5269578E+03
  0.1158768E+02 -0.1145763E+04  0.5269578E+03
  0.1576563E+02 -0.7511345E+03 -0.1576563E+02

"UES" implies displacement values and "PES" defines traction values.  So in
the example above, for element '1' with '4' nodes.  The displacements at all
4 nodes in all 3 directions is 0.  The traction values are non-zero.  The
order of the values corresponds to the order of the nodes in the .bes file.

The .con file contains the stresses and is formatted similarly.
 

Return to BES download page...