/**
         * Converts {@link FMatrix6x6} into {@link FMatrixRMaj}.
         *
         * @param input Input matrix.
         * @param output Output matrix.  If null a new matrix will be declared.
         * @return Converted matrix.
         */
        public static FMatrixRMaj convert(FMatrix6x6 input, FMatrixRMaj output)
        {
            if (output == null)
            {
                output = new FMatrixRMaj(6, 6);
            }

            if (input.getNumRows() != output.getNumRows())
            {
                throw new ArgumentException("Number of rows do not match");
            }
            if (input.getNumCols() != output.getNumCols())
            {
                throw new ArgumentException("Number of columns do not match");
            }

            output.data[0]  = input.a11;
            output.data[1]  = input.a12;
            output.data[2]  = input.a13;
            output.data[3]  = input.a14;
            output.data[4]  = input.a15;
            output.data[5]  = input.a16;
            output.data[6]  = input.a21;
            output.data[7]  = input.a22;
            output.data[8]  = input.a23;
            output.data[9]  = input.a24;
            output.data[10] = input.a25;
            output.data[11] = input.a26;
            output.data[12] = input.a31;
            output.data[13] = input.a32;
            output.data[14] = input.a33;
            output.data[15] = input.a34;
            output.data[16] = input.a35;
            output.data[17] = input.a36;
            output.data[18] = input.a41;
            output.data[19] = input.a42;
            output.data[20] = input.a43;
            output.data[21] = input.a44;
            output.data[22] = input.a45;
            output.data[23] = input.a46;
            output.data[24] = input.a51;
            output.data[25] = input.a52;
            output.data[26] = input.a53;
            output.data[27] = input.a54;
            output.data[28] = input.a55;
            output.data[29] = input.a56;
            output.data[30] = input.a61;
            output.data[31] = input.a62;
            output.data[32] = input.a63;
            output.data[33] = input.a64;
            output.data[34] = input.a65;
            output.data[35] = input.a66;

            return(output);
        }