SOR Line
The SOR Line node () handles settings for the SOR line iterative method. This is a method of SOR type with added functionality useful for, for example, anisotropic meshes. It is a block SOR solver, where the blocks are formed from lines of nodes that are relatively close to each other. In addition, ordinary SSOR iterations are performed for all degrees of freedom after the SOR Line iterations have been performed. This node can be used together with the Iterative, Krylov Preconditioner, Presmoother, Postsmoother, or Coarse Solver nodes. Also see The SOR Line Algorithm.
Main
Settings When Used With Any Attribute Node
Use the Relaxation factor field to specify a scalar relaxation factor that controls the damping of the block SOR smoothing steps. The allowed values of this factor are between 0 and 2 (default: 0.5). See About the Relaxation Factor for more information.
Use the Line based on list to control if the lines of nodes are based on the Mesh (the default) or on a Matrix. If you select Matrix, also define the Maximum line length (default: 20). This values determines the maximum length of the lines in number of DOFs for each block.
Use the Multivariable method list to control the line updates:
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If Uncoupled is selected, each block SOR smoothing step updates a set of degrees of freedom with the same name that are located on a line.
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If Coupled is selected (the default), each block SOR smoothing step updates all degrees of freedom located on a line.
For smoothing of the turbulence variables K and ε, Coupled is recommended.
The Blocked version check box is selected by default and it uses a version of the SOR method that is optimized for parallel computations.
Select the Reuse data check box (selected by default) to reuse data in order to improve the efficiency of the SOR Line method. In addition, select the Reuse lines (selected by default) check box to also reuse the SOR lines of nodes. Note that when lines are reused as a performance enhancement, it is not fully certain that the optimal lines are used.
Settings With and Without a Coarse Solver
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If used with a Coarse Solver, select a Termination technique. These are described for the SCGS attribute under Settings When Used With a Coarse Solver.
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If a Coarse Solver is not used, enter the Number of iterations to specify a fixed number of iterations to perform when this attribute is used as a preconditioner or smoother (default: 2).
Secondary
Use the Number of secondary iterations field to specify the number of SSOR iterations to perform after the SOR Line iterations have been performed (default: 1).
Use the Relaxation factor field to specify a scalar relaxation factor that controls the damping of the SSOR updates for the iterations specified in the Number of secondary iterations field. The allowed values of this factor are between 0 and 2 (default: 0.7). See About the Relaxation Factor for more information.