docs: public static DMatrixRMaj createReflector(DMatrix1Row u ) {
          if( !MatrixFeatures_DDRM.isVector(u))
              throw new IllegalArgumentException("u must be a vector");
  
          double norm = NormOps_DDRM.fastNormF(u);
          double gamma = -2.0/(norm*norm);
  
          DMatrixRMaj Q = CommonOps_DDRM.identity(u.getNumElements());
          CommonOps_DDRM.multAddTransB(gamma,u,u,Q);
  
          return Q;
      }