+ xi=c(1,nres+i)
+ yi=c(2,nres+i)
+ zi=c(3,nres+i)
+C returning the ith atom to box
+ xi=mod(xi,boxxsize)
+ if (xi.lt.0) xi=xi+boxxsize
+ yi=mod(yi,boxysize)
+ if (yi.lt.0) yi=yi+boxysize
+ zi=mod(zi,boxzsize)
+ if (zi.lt.0) zi=zi+boxzsize
+ if ((zi.gt.bordlipbot)
+ &.and.(zi.lt.bordliptop)) then
+C the energy transfer exist
+ if (zi.lt.buflipbot) then
+C what fraction I am in
+ fracinbuf=1.0d0-
+ & ((zi-bordlipbot)/lipbufthick)
+C lipbufthick is thickenes of lipid buffore
+ sslipi=sscalelip(fracinbuf)
+ ssgradlipi=-sscagradlip(fracinbuf)/lipbufthick
+ elseif (zi.gt.bufliptop) then
+ fracinbuf=1.0d0-((bordliptop-zi)/lipbufthick)
+ sslipi=sscalelip(fracinbuf)
+ ssgradlipi=sscagradlip(fracinbuf)/lipbufthick
+ else
+ sslipi=1.0d0
+ ssgradlipi=0.0
+ endif
+ else
+ sslipi=0.0d0
+ ssgradlipi=0.0
+ endif
+ xj=c(1,nres+j)
+ yj=c(2,nres+j)
+ zj=c(3,nres+j)
+C returning jth atom to box
+ xj=mod(xj,boxxsize)
+ if (xj.lt.0) xj=xj+boxxsize
+ yj=mod(yj,boxysize)
+ if (yj.lt.0) yj=yj+boxysize
+ zj=mod(zj,boxzsize)
+ if (zj.lt.0) zj=zj+boxzsize
+ if ((zj.gt.bordlipbot)
+ &.and.(zj.lt.bordliptop)) then
+C the energy transfer exist
+ if (zj.lt.buflipbot) then
+C what fraction I am in
+ fracinbuf=1.0d0-
+ & ((zj-bordlipbot)/lipbufthick)
+C lipbufthick is thickenes of lipid buffore
+ sslipj=sscalelip(fracinbuf)
+ ssgradlipj=-sscagradlip(fracinbuf)/lipbufthick
+ elseif (zj.gt.bufliptop) then
+ fracinbuf=1.0d0-((bordliptop-zj)/lipbufthick)
+ sslipj=sscalelip(fracinbuf)
+ ssgradlipj=sscagradlip(fracinbuf)/lipbufthick
+ else
+ sslipj=1.0d0
+ ssgradlipj=0.0
+ endif
+ else
+ sslipj=0.0d0
+ ssgradlipj=0.0
+ endif
+ aa=aa_lip(itypi,itypj)*(sslipi+sslipj)/2.0d0
+ & +aa_aq(itypi,itypj)*(2.0d0-sslipi-sslipj)/2.0d0
+ bb=bb_lip(itypi,itypj)*(sslipi+sslipj)/2.0d0
+ & +bb_aq(itypi,itypj)*(2.0d0-sslipi-sslipj)/2.0d0