On Fri, Jun 11, 2010, Antonios Samiotakis wrote:
> I don't understand what takes place in the ew_directp.h file.
>
>
> ! prologue: gather the data and put it in temporary arrays.
>
> n=ipairs(m)
> itran=ishft(n,-27)
> n = iand(n,mask27)
> j = bckptr(n)
>
> delx = imagcrds(1,n) + xktran(1,itran)
> dely = imagcrds(2,n) + xktran(2,itran)
> delz = imagcrds(3,n) + xktran(3,itran)
> delr2 = delx*delx + dely*dely+delz*delz
Once you have delx, dely, delz, it should be straightforward to compute
any function of r, and its derivatives. The "epilogue" file shows the actual
compution of evdw (the contribution of the LJ 12/6 terms to the energy) and
the update to the force array.
It may be more difficult than this, depending on exactly what you want to do,
but some of the internal manipulations are probably not relevant (?)
....dac
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Received on Fri Jun 11 2010 - 18:00:03 PDT
