/// <summary>
/// Solves A*X=B for X using a previously QR factored matrix.
/// </summary>
/// <param name="q">The Q matrix obtained by QR factor. This is only used for the managed provider and can be
/// <c>null</c> for the native provider. The native provider uses the Q portion stored in the R matrix.</param>
/// <param name="r">The R matrix obtained by calling <see cref="QRFactor(double[],int,int,double[],double[])"/>. </param>
/// <param name="rowsR">The number of rows in the A matrix.</param>
/// <param name="columnsR">The number of columns in the A matrix.</param>
/// <param name="tau">Contains additional information on Q. Only used for the native solver
/// and can be <c>null</c> for the managed provider.</param>
/// <param name="b">On entry the B matrix; on exit the X matrix.</param>
/// <param name="columnsB">The number of columns of B.</param>
/// <param name="x">On exit, the solution matrix.</param>
/// <param name="work">The work array - only used in the native provider. The array must have a length of at least N,
/// but should be N*blocksize. The blocksize is machine dependent. On exit, work[0] contains the optimal
/// work size value.</param>
/// <remarks>Rows must be greater or equal to columns.</remarks>
public override void QRSolveFactored(double[] q, double[] r, int rowsR, int columnsR, double[] tau, double[] b, int columnsB, double[] x, double[] work)
{
if (r == null)
{
throw new ArgumentNullException("r");
}
if (q == null)
{
throw new ArgumentNullException("q");
}
if (b == null)
{
throw new ArgumentNullException("q");
}
if (x == null)
{
throw new ArgumentNullException("q");
}
if (work == null)
{
throw new ArgumentNullException("work");
}
if (r.Length != rowsR * columnsR)
{
throw new ArgumentException(Resources.ArgumentArraysSameLength, "r");
}
if (q.Length != rowsR * rowsR)
{
throw new ArgumentException(Resources.ArgumentArraysSameLength, "q");
}
if (b.Length != rowsR * columnsB)
{
throw new ArgumentException(Resources.ArgumentArraysSameLength, "b");
}
if (x.Length != columnsR * columnsB)
{
throw new ArgumentException(Resources.ArgumentArraysSameLength, "x");
}
if (rowsR < columnsR)
{
throw new ArgumentException(Resources.RowsLessThanColumns);
}
if (work.Length < 1)
{
work[0] = rowsR * Control.BlockSize;
throw new ArgumentException(Resources.WorkArrayTooSmall, "work");
}
SafeNativeMethods.d_qr_solve_factored(rowsR, columnsR, columnsB, r, b, tau, x, work, work.Length);
}
