Package org.flag4j.linalg.solvers.exact.triangular

Class BackSolver<T extends MatrixMixin<T,?,?,?,?,?,U,?>,U extends VectorMixin<U,?,?,?,?,T,?,?>,V>

java.lang.Object

org.flag4j.linalg.solvers.exact.triangular.BackSolver<T,U,V>

Type Parameters:

T - Type of matrix to decompose.

U - Vector type equivalent of matrix.

V - Type of internal storage for the matrix and vector.

All Implemented Interfaces:

LinearSolver<T,U>

Direct Known Subclasses:

ComplexBackSolver, RealBackSolver

public abstract class BackSolver<T extends MatrixMixin<T,?,?,?,?,?,U,?>,U extends VectorMixin<U,?,?,?,?,T,?,?>,V>
extends Object
implements LinearSolver<T,U>

Base class for solvers which solve a linear system of equations U*x=b or U*X=B where U is an upper triangular matrix. This is solved in an exact sense.

Field Summary

Fields

Modifier and Type	Field	Description
protected final boolean	enforceTriU	Flag indicating if determinant should be computed.
protected static final double	RANK_CONDITION	Threshold for determining if a determinant is to be considered zero when checking if the coefficient matrix is full rank.
protected U	x	For storing vector results.
protected T	X	For storing matrix results.
protected V	xCol	For temporary storage of matrix columns to help improve cache performance.

Constructor Summary

Constructors

Constructor	Description
BackSolver(boolean enforceTriU)	Creates a solver for solving linear systems for upper triangular coefficient matrices.

Method Summary

Modifier and Type	Method	Description
protected void	checkParams(T coeff, int constantRows)	Ensures passed parameters are valid for the back solver.
protected void	checkSingular(double detAbs, int numRows, int numCols)	Checks if the coefficient matrix is singular based on the computed determinant.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.flag4j.linalg.solvers.LinearSolver

solve, solve

Field Details

X

protected T extends MatrixMixin<T,?,?,?,?,?,U,?> X

For storing matrix results.

x

protected U extends VectorMixin<U,?,?,?,?,T,?,?> x

For storing vector results.

xCol

protected V xCol

For temporary storage of matrix columns to help improve cache performance.

enforceTriU

protected final boolean enforceTriU

Flag indicating if determinant should be computed.

RANK_CONDITION

protected static final double RANK_CONDITION

Threshold for determining if a determinant is to be considered zero when checking if the coefficient matrix is full rank.

Constructor Details

BackSolver

public BackSolver(boolean enforceTriU)

Creates a solver for solving linear systems for upper triangular coefficient matrices.

Parameters:

enforceTriU - Flag indicating if an explicit check should be made that the coefficient matrix is upper triangular.

Method Details

checkParams

protected void checkParams(T coeff,
 int constantRows)

Ensures passed parameters are valid for the back solver.

Parameters:

coeff - Coefficient matrix in the linear system.

constantRows - Number of rows in the constant vector or matrix.

Throws:

IllegalArgumentException - If coeff is not square, coeff.numRows()!=constantRows, or if enforceTriU is true and coeff is not upper triangular.

checkSingular

protected void checkSingular(double detAbs,
 int numRows,
 int numCols)

Checks if the coefficient matrix is singular based on the computed determinant.

Parameters:

detAbs - Absolute value of computed determinant.

numRows - Number of rows in the coefficient matrix.

numCols - Number of columns in the coefficient matrix.