SOR Gauge
The SOR Gauge node () handles settings for the SOR gauge iterative method. This is a method of SOR-type with added functionality, useful as preconditioner/smoother for, for example, 3D magnetostatics in the AC/DC Module discretized with vector elements. In short, the added functionality consists of divergence cleaning for degrees of freedom discretized with vector elements. This node can be used together with the Iterative, Krylov Preconditioner, Presmoother, Postsmoother, or Coarse Solver nodes.
Also see The SSOR Gauge, SOR Gauge, and SORU Gauge Algorithms.
Main
Settings When Used With Any Attribute Node
Use the Solver list to specify which variant of the SOR Gauge algorithm to use. Each variant first performs one ordinary SOR iteration followed by one or several divergence cleaning iterations. Select:
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SSOR gauge (the default) to perform an ordinary SSOR iteration followed by divergence cleaning.
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SOR gauge to perform an ordinary SOR iteration followed by divergence cleaning.
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SORU gauge to perform an ordinary SORU iteration followed by divergence cleaning.
Specify a scalar Relaxation factor ω. The allowed values of this factor are between 0 and 2 (default: 1). See About the Relaxation Factor for more information.
The Blocked version check box is selected by default and it uses a version of the SOR Gauge method that is optimized for parallel computations.
Use the Variables list to specify variables to include in the divergence cleaning phase of an SOR Gauge iteration. By default, all vector degrees of freedom are included.
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). In addition to the initial divergence cleaning, the method performs a number of cleaning iterations in each linear solver iteration. Control the number of such divergence cleaning iterations in the Number of secondary iterations field.
Secondary
Use the Number of secondary iterations field to specify the number of divergence cleaning iterations to perform for each main iteration (default: 1).