pdf_sigma_sdev_2d Subroutine

subroutine pdf_sigma_sdev_2d(self,sdev,Nvec,h)
  type(pdf_kernel_2d) :: self    
  real(8)             :: sdev(2)
  integer             :: Nvec(2)
  real(8)             :: h(2,2)
  if(.not.self%status)stop "PDF_SET_SIGMA: PDF not allocated"
  h      = 0d0
  h(1,1) = (1d0/Nvec(1))**(2/6d0)*sdev(1)**2 !Silverman's rule of thumb.
  h(2,2) = (1d0/Nvec(2))**(2/6d0)*sdev(2)**2 !Silverman's rule of thumb.
end subroutine pdf_sigma_sdev_2d