public override void QRSolveFactored(float[] q, float[] r, int rowsA, int columnsA, float[] tau, float[] b, int columnsB, float[] x, float[] work, QRMethod method = QRMethod.Full)
        {
            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");
            }

            int rowsQ, columnsQ, rowsR, columnsR;

            if (method == QRMethod.Full)
            {
                rowsQ    = columnsQ = rowsR = rowsA;
                columnsR = columnsA;
            }
            else
            {
                rowsQ    = rowsA;
                columnsQ = rowsR = columnsR = columnsA;
            }

            if (r.Length != rowsR * columnsR)
            {
                throw new ArgumentException(string.Format(Resources.ArgumentArrayWrongLength, rowsR * columnsR), "r");
            }

            if (q.Length != rowsQ * columnsQ)
            {
                throw new ArgumentException(string.Format(Resources.ArgumentArrayWrongLength, rowsQ * columnsQ), "q");
            }

            if (b.Length != rowsA * columnsB)
            {
                throw new ArgumentException(string.Format(Resources.ArgumentArrayWrongLength, rowsA * columnsB), "b");
            }

            if (x.Length != columnsA * columnsB)
            {
                throw new ArgumentException(string.Format(Resources.ArgumentArrayWrongLength, columnsA * columnsB), "x");
            }

            if (work.Length < 1)
            {
                work[0] = rowsA * Control.BlockSize;
                throw new ArgumentException(Resources.WorkArrayTooSmall, "work");
            }

            if (method == QRMethod.Full)
            {
                SafeNativeMethods.s_qr_solve_factored(rowsA, columnsA, columnsB, r, b, tau, x, work, work.Length);
            }
            else
            {
                // we don't have access to the raw Q matrix any more(it is stored in R in the full QR), need to think about this.
                // let just call the managed version in the meantime. The heavy lifting has already been done. -marcus
                base.QRSolveFactored(q, r, rowsA, columnsA, tau, b, columnsB, x, QRMethod.Thin);
            }
        }