/**
         * <p>
         * Checks to see if a matrix is orthogonal or isometric.
         * </p>
         *
         * @param Q The matrix being tested. Not modified.
         * @param tol Tolerance.
         * @return True if it passes the test.
         */
        public static bool isOrthogonal(DMatrixRMaj Q, double tol)
        {
            if (Q.numRows < Q.numCols)
            {
                throw new ArgumentException("The number of rows must be more than or equal to the number of columns");
            }

            DMatrixRMaj[] u = CommonOps_DDRM.columnsToVector(Q, null);

            for (int i = 0; i < u.Count(); i++)
            {
                DMatrixRMaj a = u[i];

                for (int j = i + 1; j < u.Count(); j++)
                {
                    double val = VectorVectorMult_DDRM.innerProd(a, u[j]);

                    if (!(Math.Abs(val) <= tol))
                    {
                        return(false);
                    }
                }
            }

            return(true);
        }