7

If you call wfn.compute_hessian(), Psi4 tries to compute the nuclear Hessian which is indeed not implemented for most methods. Calling np.gradient is not advisable, as it merely computes finite-difference approximations of derivatives instead of the true derivative. This is especially going to be a problem for cube files, since the resolution is poor from ...


7

Not a full answer of an alternative program, but just collecting the conclusions from the comments along with some additional suggestions. It appears that compute_gradient and compute_hessian aren't implemented yet for wavefunction objects in Psi4. Even still, what you are interested in is the density and its gradient/hessian rather than those of the ...


4

You could simplify long range interaction by reducing precision with range. Useful algorithm for it is: https://en.wikipedia.org/wiki/Barnes%E2%80%93Hut_simulation It is usually used for gravity, but it can be applied for other forces too. With it you can do something better than just to ignore long range interaction, as is usually done, especially important ...


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