ESTS0332 QMESH,RENUM,QPLOT.
QMESH RENUM QPLOT, Self-Organizing Mesh Generator
NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHORS, MATERIAL, CATEGORIES
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| Program name | Package id | Status | Status date |
|---|---|---|---|
| QMESH,RENUM,QPLOT | ESTS0332/01 | Arrived | 15-JUN-2001 |
| QMESH,RENUM,QPLOT | ESTS0332/02 | Arrived | 15-JUN-2001 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| ESTS0332/01 | CRAY 1 | |
| ESTS0332/02 | IBM 3033 |
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3. DESCRIPTION OF PROBLEM OR FUNCTION
A set of five programs which make up a self-organising mesh generation package. QMESH generates meshes having quadrilateral elements on arbitrarily-shaped, two-dimensional (planar or axisymmetric) bodies. It is designed for use with two-dimensional finite element analysis applications. A
flexible hierarchical input scheme is used to describe bodies to QMESH as collections of regions. A mesh for each region is developed independently, with the final assembly and bandwidth minimization performed by the independent program, RENUM or RENUM8. RENUM is applied when four-node elements are desired. Eight-node elements (with mid-side nodes) may be obtained with RENUM8., QPLOT and QPLOT8 are plot programs for meshes generated by the QMESH/RENUM and QMESH/RENUM8 program pairs, respectively. QPLOT and QPLOT8 automatically section the mesh into appropriately-sized sections for legible display of node and element numbers. An overall plot showing the position of the selected plot areas is produced.
A set of five programs which make up a self-organising mesh generation package. QMESH generates meshes having quadrilateral elements on arbitrarily-shaped, two-dimensional (planar or axisymmetric) bodies. It is designed for use with two-dimensional finite element analysis applications. A
flexible hierarchical input scheme is used to describe bodies to QMESH as collections of regions. A mesh for each region is developed independently, with the final assembly and bandwidth minimization performed by the independent program, RENUM or RENUM8. RENUM is applied when four-node elements are desired. Eight-node elements (with mid-side nodes) may be obtained with RENUM8., QPLOT and QPLOT8 are plot programs for meshes generated by the QMESH/RENUM and QMESH/RENUM8 program pairs, respectively. QPLOT and QPLOT8 automatically section the mesh into appropriately-sized sections for legible display of node and element numbers. An overall plot showing the position of the selected plot areas is produced.
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4. METHOD OF SOLUTION
The mesh generating process for each individual region begins with the installation of an initial mesh which is a transformation of a regular grid on the unit square. The dimensions and orientation of the initial mesh may be defined by the user or, optionally, may be chosen by QMESH. Various smoothing algorithms may be applied to the initial mesh. Then, the mesh may be "restructured" using an iterative scheme involving "element pair restructuring", "acute element deletion", and smoothing. In element pair restructuring, the interface side between two elements is removed and placed between two different nodes belonging to the pair of elements, provided that the change produces an overall improvement in the shapes of the two elements. In acute element deletion, an element having one diagonal much shorter than the other is deleted by collapsing the short diagonal to zero length The exact order in which restructuring, element deletion, and smoothing are performed may be controlled by use of "scheme" input information. The scheme input provision also allows the user to control plotting and printing. The resulting mesh descriptions for individual regions are melded into an integrated mesh by the companion program, RENUM, which also performs bandwidth minimization using a modified Cuthill-McKee algorithm. RENUM8 performs essentially the same process as RENUM, then interpolates (linearly or by circular fit) to find mid-side node positions. It then relabels the entire mesh to maintain near-minimal bandwidth. QPLOT and QPLOT8 automatically plot meshes processed by RENUM and RENUM8, respectively. Appropriate sections of the mesh for plotting are selected by an iterative techniques which determines the size and position of each section, so as to include the smallest as yet unlabelled element in each successive section.
The mesh generating process for each individual region begins with the installation of an initial mesh which is a transformation of a regular grid on the unit square. The dimensions and orientation of the initial mesh may be defined by the user or, optionally, may be chosen by QMESH. Various smoothing algorithms may be applied to the initial mesh. Then, the mesh may be "restructured" using an iterative scheme involving "element pair restructuring", "acute element deletion", and smoothing. In element pair restructuring, the interface side between two elements is removed and placed between two different nodes belonging to the pair of elements, provided that the change produces an overall improvement in the shapes of the two elements. In acute element deletion, an element having one diagonal much shorter than the other is deleted by collapsing the short diagonal to zero length The exact order in which restructuring, element deletion, and smoothing are performed may be controlled by use of "scheme" input information. The scheme input provision also allows the user to control plotting and printing. The resulting mesh descriptions for individual regions are melded into an integrated mesh by the companion program, RENUM, which also performs bandwidth minimization using a modified Cuthill-McKee algorithm. RENUM8 performs essentially the same process as RENUM, then interpolates (linearly or by circular fit) to find mid-side node positions. It then relabels the entire mesh to maintain near-minimal bandwidth. QPLOT and QPLOT8 automatically plot meshes processed by RENUM and RENUM8, respectively. Appropriate sections of the mesh for plotting are selected by an iterative techniques which determines the size and position of each section, so as to include the smallest as yet unlabelled element in each successive section.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM
QMESH - Maxima of
1,000 nodes
400 lines
100 sides
70 regions
RENUM- Maxima of
15,000 nodes (Cray1,IBM3033)
10,000 elements (Cray1,IBM3033)
QPLOT - Maxima of
5,000 nodes
4,800 elements
RENUM8 - Maxima of
10,000 output nodes (Cray1,IBM3033)
5,000 input nodes
4,800 elements
Non-straight lines should have at least two intervals, as mid-side node placement is always done linearly for lines with only one interval. Corner lines should not be used, as circular interpolation on region boundaries could produce unreasonable results near the actual corner.
QPLOT8 - Maxima of
20,000 nodes (Cray1)
10,000 elements (Cray1)
QMESH - Maxima of
1,000 nodes
400 lines
100 sides
70 regions
RENUM- Maxima of
15,000 nodes (Cray1,IBM3033)
10,000 elements (Cray1,IBM3033)
QPLOT - Maxima of
5,000 nodes
4,800 elements
RENUM8 - Maxima of
10,000 output nodes (Cray1,IBM3033)
5,000 input nodes
4,800 elements
Non-straight lines should have at least two intervals, as mid-side node placement is always done linearly for lines with only one interval. Corner lines should not be used, as circular interpolation on region boundaries could produce unreasonable results near the actual corner.
QPLOT8 - Maxima of
20,000 nodes (Cray1)
10,000 elements (Cray1)
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6. TYPICAL RUNNING TIME
Meshes of up to several hundred elements which do not require restructuring are handled by QMESH in a few seconds. Large meshes involving much restructuring and smoothing may require several minutes of execution time. RENUM and RENUM8 requires a few seconds at most. QPLOT and QPLOT8 usually run in a
fraction of the time required by QMESH on a nontrivial problem.
Meshes of up to several hundred elements which do not require restructuring are handled by QMESH in a few seconds. Large meshes involving much restructuring and smoothing may require several minutes of execution time. RENUM and RENUM8 requires a few seconds at most. QPLOT and QPLOT8 usually run in a
fraction of the time required by QMESH on a nontrivial problem.
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| Package ID | Status date | Status |
|---|---|---|
| ESTS0332/01 | 15-JUN-2001 | Masterfiled Arrived |
| ESTS0332/02 | 15-JUN-2001 | Masterfiled Arrived |
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10. REFERENCES
- Rondall E. Jones, The QMESH Mesh Generation Package, Association
for Computing Machinery SIGNUM Newsletter, Vol. 10, No. 4, pp.
31-34, December 1975.
- Rondall E. Jones, The QMESH Mesh Generation Package, Association
for Computing Machinery SIGNUM Newsletter, Vol. 10, No. 4, pp.
31-34, December 1975.
ESTS0332/01, included references:
- R.E. Jones:QMESH - A Self-Organizing Mesh Generation Program
SLA-73-1088 (July 1974).
- R.E. Jones:
Users' Manual for QMESH, A Self-Organizing Mesh Generation
Program
SLA-74-0239 (July 1974).
- L. Eyberger:
QMESH,RENUM,QPLOT, NESC No. 612.3033, QMESH,RENUM,QPLOT CRAY1
Version Tape Description and Sample Problem Output,
NESC Note 92-28 (November 15, 1991).
ESTS0332/02, included references:
- R.E. Jones:QMESH - A Self-Organizing Mesh Generation Program
SLA-73-1088 (July 1974).
- R.E. Jones:
Users' Manual for QMESH, A Self-Organizing Mesh Generation
Program
SLA-74-0239 (July 1974).
- L. Eyberger:
QMESH,RENUM,QPLOT, NESC No. 612.3033, QMESH,RENUM,QPLOT IBM
Version Tape Description and Sample Problem Output,
NESC Note 92-29 (November 15, 1991).
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| Package ID | Computer language |
|---|---|
| ESTS0332/01 | FORTRAN |
| ESTS0332/02 | FORTRAN |
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
The
mesh plotted by QMESH does not include any mid-side nodes, and RENUM8 input cannot refer to any mid-side nodes. Mid-side nodes appear only in QPLOT8 plots.
The Crayl version uses the SNLA-environment Graphics Compatibility System (GCS) library to generate graphics output. Suitable alternatives are required for graphics output in other environments. Calls to the plotting package can be eliminated if no P character is included in the scheme input.
The
mesh plotted by QMESH does not include any mid-side nodes, and RENUM8 input cannot refer to any mid-side nodes. Mid-side nodes appear only in QPLOT8 plots.
The Crayl version uses the SNLA-environment Graphics Compatibility System (GCS) library to generate graphics output. Suitable alternatives are required for graphics output in other environments. Calls to the plotting package can be eliminated if no P character is included in the scheme input.
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ESTS0332/01
source program mag tapeQMESH FORTRAN Source SRCTPsource program mag tapeRENUM FORTRAN Source SRCTP
source program mag tapeQPLOT FORTRAN Source SRCTP
source program mag tapeRENUM8 FORTRAN Source SRCTP
source program mag tapeQPLOT8 FORTRAN Source SRCTP
test-case data mag tapeQMESH Sample problem input DATTP
test-case data mag tapeRENUM Sample problem input DATTP
test-case data mag tapeRENUM8 Sample problem input DATTP
test-case data mag tapeControl information (JCL) DATTP
report SLA-74-0239 (July 1974) REPPT
report SLA-73-1088 (July 1974) REPPT
prog. note NESC Note 92-28 (November 15, 1991) NOTPT
ESTS0332/02
source program mag tapeQMESH FORTRAN Source SRCTPsource program mag tapeRENUM FORTRAN Source SRCTP
source program mag tapeQPLOT FORTRAN Source SRCTP
source program mag tapeRENUM8 FORTRAN Source SRCTP
source program mag tapeQPLOT8 FORTRAN Source SRCTP
source program mag tapeSubroutine CLOCK BAL Source SRCTP
source program mag tapeSubroutine DATE BAL Source SRCTP
source program mag tapeFunction ITIMER BAL Source SRCTP
test-case data mag tapeQMESH Sample problem input DATTP
test-case data mag tapeRENUM Sample problem input DATTP
test-case data mag tapeRENUM8 Sample problem input DATTP
test-case data mag tapeControl information (JCL) DATTP
report SLA-74-0239 (July 1974) REPPT
report SLA-73-1088 (July 1974) REPPT
prog. note NESC Note 92-29 (November 15, 1991) NOTPT
Keywords: bandwidth minimization, finite element method, mesh generation, two-dimensional.