/**
* Returns an estimate of the solution to the linear system A · x = b.
*
* @param a the linear operator A of the system
* @param b the right-hand side vector
* @return a new vector containing the solution
* @throws NullArgumentException if one of the parameters is {@code null}
* @throws NonSquareOperatorException if {@code a} is not square
* @throws DimensionMismatchException if {@code b} has dimensions inconsistent with {@code a}
* @throws MaxCountExceededException at exhaustion of the iteration count, unless a custom {@link
* org.apache.commons.math3.util.Incrementor.MaxCountExceededCallback callback} has been set
* at construction of the {@link IterationManager}
*/
public RealVector solve(final RealLinearOperator a, final RealVector b)
throws NullArgumentException, NonSquareOperatorException, DimensionMismatchException,
MaxCountExceededException {
MathUtils.checkNotNull(a);
final RealVector x = new ArrayRealVector(a.getColumnDimension());
x.set(0.);
return solveInPlace(a, b, x);
}
/**
* Performs all dimension checks on the parameters of {@link #solve(RealLinearOperator,
* RealVector, RealVector) solve} and {@link #solveInPlace(RealLinearOperator, RealVector,
* RealVector) solveInPlace}, and throws an exception if one of the checks fails.
*
* @param a the linear operator A of the system
* @param b the right-hand side vector
* @param x0 the initial guess of the solution
* @throws NullArgumentException if one of the parameters is {@code null}
* @throws NonSquareOperatorException if {@code a} is not square
* @throws DimensionMismatchException if {@code b} or {@code x0} have dimensions inconsistent with
* {@code a}
*/
protected static void checkParameters(
final RealLinearOperator a, final RealVector b, final RealVector x0)
throws NullArgumentException, NonSquareOperatorException, DimensionMismatchException {
MathUtils.checkNotNull(a);
MathUtils.checkNotNull(b);
MathUtils.checkNotNull(x0);
if (a.getRowDimension() != a.getColumnDimension()) {
throw new NonSquareOperatorException(a.getRowDimension(), a.getColumnDimension());
}
if (b.getDimension() != a.getRowDimension()) {
throw new DimensionMismatchException(b.getDimension(), a.getRowDimension());
}
if (x0.getDimension() != a.getColumnDimension()) {
throw new DimensionMismatchException(x0.getDimension(), a.getColumnDimension());
}
}
