org.apache.commons.math3.linear

## Interface DecompositionSolver

• public interface DecompositionSolver
Interface handling decomposition algorithms that can solve A × X = B.

Decomposition algorithms decompose an A matrix has a product of several specific matrices from which they can solve A × X = B in least squares sense: they find X such that ||A × X - B|| is minimal.

Some solvers like LUDecomposition can only find the solution for square matrices and when the solution is an exact linear solution, i.e. when ||A × X - B|| is exactly 0. Other solvers can also find solutions with non-square matrix A and with non-null minimal norm. If an exact linear solution exists it is also the minimal norm solution.

Since:
2.0
Version:
$Id: DecompositionSolver.java 1416643 2012-12-03 19:37:14Z tn$
• ### Method Summary

Methods
Modifier and Type Method and Description
RealMatrix getInverse()
Get the inverse (or pseudo-inverse) of the decomposed matrix.
boolean isNonSingular()
Check if the decomposed matrix is non-singular.
RealMatrix solve(RealMatrix b)
Solve the linear equation A × X = B for matrices A.
RealVector solve(RealVector b)
Solve the linear equation A × X = B for matrices A.
• ### Method Detail

• #### solve

RealVector solve(RealVector b)
Solve the linear equation A × X = B for matrices A.

The A matrix is implicit, it is provided by the underlying decomposition algorithm.

Parameters:
b - right-hand side of the equation A × X = B
Returns:
a vector X that minimizes the two norm of A × X - B
Throws:
DimensionMismatchException - if the matrices dimensions do not match.
SingularMatrixException - if the decomposed matrix is singular.
• #### solve

RealMatrix solve(RealMatrix b)
Solve the linear equation A × X = B for matrices A.

The A matrix is implicit, it is provided by the underlying decomposition algorithm.

Parameters:
b - right-hand side of the equation A × X = B
Returns:
a matrix X that minimizes the two norm of A × X - B
Throws:
DimensionMismatchException - if the matrices dimensions do not match.
SingularMatrixException - if the decomposed matrix is singular.
• #### isNonSingular

boolean isNonSingular()
Check if the decomposed matrix is non-singular.
Returns:
true if the decomposed matrix is non-singular.
• #### getInverse

RealMatrix getInverse()
Get the inverse (or pseudo-inverse) of the decomposed matrix.
Returns:
inverse matrix
Throws:
SingularMatrixException - if the decomposed matrix is singular.