11.3.2 grid_orbital_values: evaluate orbital basis functions on grid

      subroutine grid_orbital_values(npt,idiff,r,val,grad,hess)
      implicit double precision (a-h,o-z)
      dimension r(3,npt),val(npt,ntg),grad(npt,ntg,3),hess(npt,ntg,6)

Evaluates the values of the basis functions and, optionally, their first and second derivatives with respect to the electronic coordinate, at supplied points in space. On input, r and npt specify the points. idiff should be 0, 1 or 2 to indicate how many times to differentiate. On exit, the orbital values are returned in val. If requested, the gradients are in grad (component ordering $x$, $y$, $z$), and the second derivatives in hess ($xx$, $yy$, $zz$, $xy$, $xz$, $yz$).