Difference between revisions of "Resequence Command"
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# Another use of this command is to verify mesh connectivity. Since disconnected sections of a static FEA mesh will cause a singular stiffness matrix, the calculations will fail. If you use a <tt>Resequence</tt> command on a disconnected mesh, it will detect the problem and abort the calculations. | # Another use of this command is to verify mesh connectivity. Since disconnected sections of a static FEA mesh will cause a singular stiffness matrix, the calculations will fail. If you use a <tt>Resequence</tt> command on a disconnected mesh, it will detect the problem and abort the calculations. | ||
# The algorithm used to resequence the nodes in described in a paper by Gibbs, Poole, and Stockmeyer.<ref name='RS'>N. E. Gibbs, W. G. Poole, and P. K. Stockmeyer, "An Algorithm for Reducing the Bandwidth and Profile of a Sparse Matrix," <i>SIAM Journal of Numerical Analysis</i>, <b>13</b>, 236-250 (1976).</ref> | # The algorithm used to resequence the nodes in described in a paper by Gibbs, Poole, and Stockmeyer.<ref name='RS'>N. E. Gibbs, W. G. Poole, and P. K. Stockmeyer, "An Algorithm for Reducing the Bandwidth and Profile of a Sparse Matrix," <i>SIAM Journal of Numerical Analysis</i>, <b>13</b>, 236-250 (1976).</ref> | ||
== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 21:44, 10 September 2013
The Resequence command is used to renumber the numbers in an attempt to minimize the bandwidth of the problem. The smaller the bandwidth, the faster will be the FEA calculations.
Scripted Input Files
The two options in scripted input files are
Resequence (x),(y)
or
Resequence (id)
where
- (x, y) define the coordinates (in mm) for a point (or (R,Z) coordinates if axisymmetric). The resequencing will start at the one node nearest to that point.
- (id) is a previously defined keypoint. The resequencing will start at the node at that keypoint.
XML Input Files
In XML files, the two options, which must be within the <GridBCs> element, are:
<Resequence x='(x)' y='(y)'/>
or
<Resequence keypt='(id)'/>
where (x), (y), and (id) are the same as defined above.
Notes
- It is best to start the resequencing at a node on the boundary of the object and probably on a corner. The final bandwidth may depend on the node selected for resequencing. The bandwidth is reported in FEA output results. You can vary the resequencing node to find the minimum value.
- Another use of this command is to verify mesh connectivity. Since disconnected sections of a static FEA mesh will cause a singular stiffness matrix, the calculations will fail. If you use a Resequence command on a disconnected mesh, it will detect the problem and abort the calculations.
- The algorithm used to resequence the nodes in described in a paper by Gibbs, Poole, and Stockmeyer.[1]
References
- ↑ N. E. Gibbs, W. G. Poole, and P. K. Stockmeyer, "An Algorithm for Reducing the Bandwidth and Profile of a Sparse Matrix," SIAM Journal of Numerical Analysis, 13, 236-250 (1976).