+C xj=c(1,j)+0.5D0*dxj-xmedi
+C yj=c(2,j)+0.5D0*dyj-ymedi
+C zj=c(3,j)+0.5D0*dzj-zmedi
+ xj=c(1,j)+0.5D0*dxj
+ yj=c(2,j)+0.5D0*dyj
+ zj=c(3,j)+0.5D0*dzj
+ 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.lt.0).or.(xj.lt.0).or.(yj.lt.0)) write (*,*) "CHUJ"
+ dist_init=(xj-xmedi)**2+(yj-ymedi)**2+(zj-zmedi)**2
+ xj_safe=xj
+ yj_safe=yj
+ zj_safe=zj
+ isubchap=0
+ do xshift=-1,1
+ do yshift=-1,1
+ do zshift=-1,1
+ xj=xj_safe+xshift*boxxsize
+ yj=yj_safe+yshift*boxysize
+ zj=zj_safe+zshift*boxzsize
+ dist_temp=(xj-xmedi)**2+(yj-ymedi)**2+(zj-zmedi)**2
+ if(dist_temp.lt.dist_init) then
+ dist_init=dist_temp
+ xj_temp=xj
+ yj_temp=yj
+ zj_temp=zj
+ isubchap=1
+ endif
+ enddo
+ enddo
+ enddo
+ if (isubchap.eq.1) then
+ xj=xj_temp-xmedi
+ yj=yj_temp-ymedi
+ zj=zj_temp-zmedi
+ else
+ xj=xj_safe-xmedi
+ yj=yj_safe-ymedi
+ zj=zj_safe-zmedi
+ endif
+C if ((i+3).lt.j) then !this condition keeps for turn3 and turn4 not subject to PBC
+c 174 continue
+c if (xj.gt.((0.5d0)*boxxsize)) xj=xj-boxxsize
+c if (xj.lt.((-0.5d0)*boxxsize)) xj=xj+boxxsize
+C Condition for being inside the proper box
+c if ((xj.gt.((0.5d0)*boxxsize)).or.
+c & (xj.lt.((-0.5d0)*boxxsize))) then
+c go to 174
+c endif
+c 175 continue
+c if (yj.gt.((0.5d0)*boxysize)) yj=yj-boxysize
+c if (yj.lt.((-0.5d0)*boxysize)) yj=yj+boxysize
+C Condition for being inside the proper box
+c if ((yj.gt.((0.5d0)*boxysize)).or.
+c & (yj.lt.((-0.5d0)*boxysize))) then
+c go to 175
+c endif
+c 176 continue
+c if (zj.gt.((0.5d0)*boxzsize)) zj=zj-boxzsize
+c if (zj.lt.((-0.5d0)*boxzsize)) zj=zj+boxzsize
+C Condition for being inside the proper box
+c if ((zj.gt.((0.5d0)*boxzsize)).or.
+c & (zj.lt.((-0.5d0)*boxzsize))) then
+c go to 176
+c endif
+C endif !endPBC condintion
+C xj=xj-xmedi
+C yj=yj-ymedi
+C zj=zj-zmedi