anchor.diff:      do iz=1,dim_quad
          do ik=1,Nk
             tmp = farr(nthread,iz,ik)
  -          gtmp = gtmp + real(jacobian(nthread,iz,ik))*tmp
  +          gtmp = gtmp + (jacobian(nthread,iz,ik))*tmp
          end do
       end do
       foldingarr = gtmp
  
positive.code: 
      f2 = cdexp((0,1)*k_wave*norm(y))*phi(x,i,hval**2)/norm(y)
    end function f2
  
    double complex function f(x,i,j)
      integer, intent(in) :: i,j
  
negative.code:     do iz=1,dim_quad
         do ik=1,Nk
            tmp = f(nodes(nthread,iz,ik,:),ip,jp)
            gtmp = gtmp + (jacobian(nthread,iz,ik))*tmp
         end do
      end do
      folding = gtmp
  