SSORPreconditioner

java.lang.Object
- org.ojalgo.matrix.task.iterative.SSORPreconditioner

All Implemented Interfaces:

Preconditioner
```
public final class SSORPreconditioner
extends java.lang.Object
implements Preconditioner
```
Symmetric Successive Over-Relaxation (SSOR) preconditioner with relaxation factor omega (ω).
For ω = 1 this reduces to a symmetric Gauss–Seidel (forward + backward) sweep – a common choice for SPD systems with suitable variable ordering.
The applied effect is an approximate M^{-1} with the classic form (D/ω + L) D^{-1} (D/ω + U) scaled by (2 - ω)/ω, implemented via forward and backward triangular sweeps.
Compatibility and guidance
- Symmetric by construction; typically positive-definite for SPD A when 0 < ω < 2.
- Useful for methods that expect a symmetric (often SPD) preconditioner.
- Can be used as a right-preconditioner in methods for general nonsymmetric systems where symmetry of M is acceptable or desired.
- Stationary fixed-point methods that ignore preconditioners will not use this.

Field Summary

Fields
Modifier and Type	Field	Description
`private R064Store`	`myDiag`
`private int`	`myDim`
`private java.util.List<Equation>`	`myEquations`
`private double`	`myOmega`
`private R064Store`	`myWorkY`
`private R064Store`	`myWorkZ`

Fields inherited from interface org.ojalgo.matrix.task.iterative.Preconditioner
IDENTITY

Constructor Summary

Constructors
Constructor Description

SSORPreconditioner()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`apply(Access1D<java.lang.Double> src, PhysicalStore<java.lang.Double> dst)`	Apply M^{-1} to a vector.
`SSORPreconditioner`	`omega(double value)`
`void`	`prepare(java.util.List<Equation> equations, int dimension)`	Prepare internal structures for a specific system.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.ojalgo.matrix.task.iterative.Preconditioner
applyTranspose

- Field Detail
  - myOmega
```
private double myOmega
```
  - myDiag
```
private transient R064Store myDiag
```
  - myWorkY
```
private transient R064Store myWorkY
```
  - myWorkZ
```
private transient R064Store myWorkZ
```
  - myEquations
```
private transient java.util.List<Equation> myEquations
```
  - myDim
```
private int myDim
```
- Constructor Detail
  - SSORPreconditioner
```
public SSORPreconditioner()
```
- Method Detail
  - apply
```
public void apply(Access1D<java.lang.Double> src,
                  PhysicalStore<java.lang.Double> dst)
```
    Description copied from interface: Preconditioner
    
    Apply M^{-1} to a vector. src and dst may alias.
    
    Specified by:
    
    apply in interface Preconditioner
  - omega
```
public SSORPreconditioner omega(double value)
```
  - prepare
```
public void prepare(java.util.List<Equation> equations,
                    int dimension)
```
    Description copied from interface: Preconditioner
    
    Prepare internal structures for a specific system. Implementations may analyse sparsity or extract diagonals/factors here.
    
    Specified by:
    
    prepare in interface Preconditioner
    
    Parameters:
    
    equations - The active set of rows constituting the system body.
    
    dimension - The vector dimension (number of variables / size of solution vector).