QgsMatrixSolver Class Reference

Contains utility functions for solving matrix operations. More...

#include <qgsmatrixsolver.h>

Classes
struct	GslData

Public Member Functions
	QgsMatrixSolver (const QgsMatrixSolver &)=delete
	QgsMatrixSolver (int maximumDimension)
	Constructor for QgsMatrixSolver, pre-allocated to solve matrices with the specified maximumDimension.
	~QgsMatrixSolver ()
int	maximumDimension () const
	Returns the maximum dimension supported by this solver.
QgsMatrixSolver &	operator= (const QgsMatrixSolver &)=delete
void	setRightHandSide (int row, double value)
	Sets a value in the preallocated right-hand-side vector b.
void	setValue (int row, int column, double value)
	Sets the value for row, column in the preallocated matrix A.
bool	solve (int dimension, QVector< double > &result, Qgis::LinearMatrixMethod method=Qgis::LinearMatrixMethod::Lu)
	Solves the system Ax = b for a specific active dimension.

Static Public Member Functions
static bool	isAvailable ()
	Returns true if the matrix solver functionality is available on the current system.

Detailed Description

Contains utility functions for solving matrix operations.

This utility class is designed to solve systems of linear equations in the form Ax = b using LU decomposition.

Note

In situations where many linear systems need to be solved sequentially this class supports a preallocation strategy. By constructing the solver initially with a maximumDimension (where maximumDimension is N for the largest N × N matrix to solve), all backend memory is allocated upfront. Subsequent calls to solve() using a specified dimension create zero-allocation views into this memory block. This guarantees that no heap allocations occur during calculations.

Warning

This class requires a QGIS build with the GSL library enabled. See isAvailable() to determine if the current system supports its functionality.

Since

QGIS 4.4

Definition at line 44 of file qgsmatrixsolver.h.

Constructor & Destructor Documentation

QgsMatrixSolver() [1/2]

QgsMatrixSolver::QgsMatrixSolver ( int maximumDimension )

explicit

Constructor for QgsMatrixSolver, pre-allocated to solve matrices with the specified maximumDimension.

Parameters

maximumDimension

The dimension N for the largest N × N matrix A to solve with this object. (E.g. 4 if a 4 × 4 matrix is the largest A to solve.)

Definition at line 65 of file qgsmatrixsolver.cpp.

~QgsMatrixSolver()

QgsMatrixSolver::~QgsMatrixSolver

(

)

Definition at line 97 of file qgsmatrixsolver.cpp.

QgsMatrixSolver() [2/2]

QgsMatrixSolver::QgsMatrixSolver ( const QgsMatrixSolver & )

delete

Member Function Documentation

isAvailable()

bool QgsMatrixSolver::isAvailable ( )

static

Returns true if the matrix solver functionality is available on the current system.

Definition at line 56 of file qgsmatrixsolver.cpp.

maximumDimension()

int QgsMatrixSolver::maximumDimension

(

)

const

Returns the maximum dimension supported by this solver.

Definition at line 139 of file qgsmatrixsolver.cpp.

operator=()

QgsMatrixSolver & QgsMatrixSolver::operator= ( const QgsMatrixSolver & )

delete

setRightHandSide()

void QgsMatrixSolver::setRightHandSide	(	int	row,
		double	value )

Sets a value in the preallocated right-hand-side vector b.

Parameters

row	The row index (0-based)
value	The value to insert

Warning

The c++ version of this method performs no bounds checking on row, this is the caller's responsibility.

Exceptions

QgsNotSupportedException

for QGIS builds without GSL support.

Definition at line 156 of file qgsmatrixsolver.cpp.

setValue()

void QgsMatrixSolver::setValue	(	int	row,
		int	column,
		double	value )

Sets the value for row, column in the preallocated matrix A.

Parameters

row	The row index (0-based)
column	The column index (0-based)
value	The value to insert

Warning

The c++ version of this method performs no bounds checking on row or column, this is the caller's responsibility.

Exceptions

QgsNotSupportedException

for QGIS builds without GSL support.

Definition at line 144 of file qgsmatrixsolver.cpp.

solve()

bool QgsMatrixSolver::solve	(	int	dimension,
		QVector< double > &	result,
		Qgis::LinearMatrixMethod	method = Qgis::LinearMatrixMethod::Lu )

Solves the system Ax = b for a specific active dimension.

Parameters

dimension	The dimension N for the N × N sub-matrix to solve.
result	Solution vector x
method	Solving strategy to use

Returns

true on success, false if the matrix is singular and could not be solved.

Exceptions

QgsNotSupportedException	for QGIS builds without GSL support.
QgsInvalidArgumentException	for invalid dimension values

Definition at line 167 of file qgsmatrixsolver.cpp.

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The documentation for this class was generated from the following files:

• /build/qgis-4.3.0+git20260904+90cb4ecf9ef+99sid/src/core/qgsmatrixsolver.h
• /build/qgis-4.3.0+git20260904+90cb4ecf9ef+99sid/src/core/qgsmatrixsolver.cpp