code: public Matrix3d mul(Matrix3dc right, Matrix3d dest) {
          double nm00 = m00 * right.m00() + m10 * right.m01() + m20 * right.m02();
          double nm01 = m01 * right.m00() + m11 * right.m01() + m21 * right.m02();
          double nm02 = m02 * right.m00() + m12 * right.m01() + m22 * right.m02();
          double nm10 = m00 * right.m10() + m10 * right.m11() + m20 * right.m12();
          double nm11 = m01 * right.m10() + m11 * right.m11() + m21 * right.m12();
          double nm12 = m02 * right.m10() + m12 * right.m11() + m22 * right.m12();
          double nm20 = m00 * right.m20() + m10 * right.m21() + m20 * right.m22();
          double nm21 = m01 * right.m20() + m11 * right.m21() + m21 * right.m22();
          double nm22 = m02 * right.m20() + m12 * right.m21() + m22 * right.m22();
          dest.m00 = nm00;
          dest.m01 = nm01;
          dest.m02 = nm02;
          dest.m10 = nm10;
          dest.m11 = nm11;
          dest.m12 = nm12;
          dest.m20 = nm20;
          dest.m21 = nm21;
          dest.m22 = nm22;
          return dest;
      }
docs: /* (non-Javadoc)
  @see org.joml.Matrix3dc#mul(org.joml.Matrix3dc, org.joml.Matrix3d)