Greetings from windy west coast!
I come across these lines in src/pmemd/src/cuda/kNLCPNE.h and realize that I need some help after struggling for a while.
Following lines deal with exclusions. For PME_ENERGY case, by propagating the correction via b0 and b1, line 365 removes both the energies and forces of what should be excluded reciprocal terms. For other cases, the force terms should also be removed. However, for (use_SPFP) && !(PME_FSWITCH), swtch is not used. How it does the trick? Any hint?
yd
src/pmemd/src/cuda/kNLCPNE.h
363: #if defined(use_DPFP) || defined(PME_FSWITCH) || defined(PME_ENERGY)
364: else {
365: swtch -= (PMEFloat)1.0;
366: }
367: #endif
// This ends a branch for "not an exclusion"--the non-bonded interaction is
// to be counted. 0x1 is simply 1 in hexadecimal.
371: #ifdef PME_ENERGY
372: PMEFloat b0 = qiqj * swtch * rinv;
373: PMEFloat b1 = b0 - qiqj * d_swtch_dx;
374: df += b1 * r2inv;
375: # ifdef use_SPFP
376: TLeed += fnrange * b0;
377: # else // use_DPFP
378: eed.pmef += fnrange * b0;
379: # endif
380: #else // PME_ENERGY
381: # if defined(use_SPFP) && !defined(PME_FSWITCH)
382: df += qiqj * d_swtch_dx;
383: # else
384: df += qiqj * (swtch * rinv - d_swtch_dx) * r2inv;
385: # endif
386: #endif // PME_ENERGY
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Received on Mon Oct 28 2019 - 14:30:02 PDT
