source/wham/src-HCD-5D/elecont.f

   1       subroutine elecont(lprint,ncont,icont,ist,ien,ipermmin)
   2       implicit none
   3       include 'DIMENSIONS'
   4       include 'DIMENSIONS.ZSCOPT'
   5       include 'DIMENSIONS.COMPAR'
   6       include 'COMMON.IOUNITS'
   7       include 'COMMON.CHAIN'
   8       include 'COMMON.INTERACT'
   9       include 'COMMON.FFIELD'
  10       include 'COMMON.NAMES'
  11       include 'COMMON.LOCAL'
  12       logical lprint
  13       integer iperm,ipermmin,ii,jj
  14       integer i,j,k,ist,ien,iteli,itelj,ind,i1,i2,it1,it2,ic1,ic2
  15       double precision rri,xi,yi,zi,dxi,dyi,dzi,xmedi,ymedi,zmedi,
  16      &  xj,yj,zj,dxj,dyj,dzj,aaa,bbb,ael6i,ael3i,rrmij,rmij,r3ij,r6ij,
  17      &  vrmij,cosa,cosb,cosg,fac,ev1,ev2,fac3,fac4,evdwij,el1,el2,
  18      &  eesij,ees,evdw,ene, rij,zj_temp,xj_temp,yj_temp,
  19      & sscale,sscagrad,dist_temp,xj_safe,yj_safe,zj_safe,dist_init
  20       double precision elpp6c(2,2),elpp3c(2,2),ael6c(2,2),ael3c(2,2),
  21      &  appc(2,2),bppc(2,2)
  22       double precision elcutoff,elecutoff_14
  23       integer ncont,icont(2,maxcont),xshift,yshift,zshift,isubchap
  24       double precision econt(maxcont)
  25 *
  26 * Load the constants of peptide bond - peptide bond interactions.
  27 * Type 1 - ordinary peptide bond, type 2 - alkylated peptide bond (e.g.
  28 * proline) - determined by averaging ECEPP energy.
  29 *
  30 * as of 7/06/91.
  31 *
  32 c      data epp    / 0.3045d0, 0.3649d0, 0.3649d0, 0.5743d0/
  33 c      data rpp    / 4.5088d0, 4.5395d0, 4.5395d0, 4.4846d0/
  34       data elpp6c  /-0.2379d0,-0.2056d0,-0.2056d0,-0.0610d0/
  35       data elpp3c  / 0.0503d0, 0.0000d0, 0.0000d0, 0.0692d0/
  36       data elcutoff /-0.3d0/,elecutoff_14 /-0.5d0/
  37       ees=0.0d0
  38       evdw=0.0d0
  39       if (lprint) write (iout,'(a)')
  40      &  "Constants of electrostatic interaction energy expression."
  41       do i=1,2
  42         do j=1,2
  43         rri=rpp(i,j)**6
  44         appc(i,j)=epp(i,j)*rri*rri
  45         bppc(i,j)=-2.0*epp(i,j)*rri
  46         ael6c(i,j)=elpp6c(i,j)*4.2**6
  47         ael3c(i,j)=elpp3c(i,j)*4.2**3
  48         if (lprint)
  49      &  write (iout,'(2i2,4e15.4)') i,j,appc(i,j),bppc(i,j),ael6c(i,j),
  50      &                               ael3c(i,j)
  51         enddo
  52       enddo
  53       ncont=0
  54       do 1 i=ist,ien-2
  55         ii=iperm(i,ipermmin)
  56         xi=c(1,ii)
  57         yi=c(2,ii)
  58         zi=c(3,ii)
  59         dxi=c(1,ii+1)-c(1,ii)
  60         dyi=c(2,ii+1)-c(2,ii)
  61         dzi=c(3,ii+1)-c(3,ii)
  62         xmedi=xi+0.5*dxi
  63         ymedi=yi+0.5*dyi
  64         zmedi=zi+0.5*dzi
  65           xmedi=mod(xmedi,boxxsize)
  66           if (xmedi.lt.0) xmedi=xmedi+boxxsize
  67           ymedi=mod(ymedi,boxysize)
  68           if (ymedi.lt.0) ymedi=ymedi+boxysize
  69           zmedi=mod(zmedi,boxzsize)
  70           if (zmedi.lt.0) zmedi=zmedi+boxzsize
  71         do 4 j=i+2,ien-1
  72           jj=iperm(j,ipermmin)
  73           ind=ind+1
  74           iteli=itel(i)
  75           itelj=itel(j)
  76           if (j.eq.i+2 .and. itelj.eq.2) iteli=2
  77           if (iteli.eq.2 .and. itelj.eq.2
  78      &      .or.iteli.eq.0 .or.itelj.eq.0) goto 4
  79           aaa=appc(iteli,itelj)
  80           bbb=bppc(iteli,itelj)
  81           ael6i=ael6c(iteli,itelj)
  82           ael3i=ael3c(iteli,itelj)
  83           dxj=c(1,jj+1)-c(1,jj)
  84           dyj=c(2,jj+1)-c(2,jj)
  85           dzj=c(3,jj+1)-c(3,jj)
  86           xj=c(1,jj)+0.5*dxj
  87           yj=c(2,jj)+0.5*dyj
  88           zj=c(3,jj)+0.5*dzj
  89           xj=mod(xj,boxxsize)
  90           if (xj.lt.0) xj=xj+boxxsize
  91           yj=mod(yj,boxysize)
  92           if (yj.lt.0) yj=yj+boxysize
  93           zj=mod(zj,boxzsize)
  94           if (zj.lt.0) zj=zj+boxzsize
  95       dist_init=(xj-xmedi)**2+(yj-ymedi)**2+(zj-zmedi)**2
  96       xj_safe=xj
  97       yj_safe=yj
  98       zj_safe=zj
  99       isubchap=0
 100       do xshift=-1,1
 101       do yshift=-1,1
 102       do zshift=-1,1
 103           xj=xj_safe+xshift*boxxsize
 104           yj=yj_safe+yshift*boxysize
 105           zj=zj_safe+zshift*boxzsize
 106           dist_temp=(xj-xmedi)**2+(yj-ymedi)**2+(zj-zmedi)**2
 107           if(dist_temp.lt.dist_init) then
 108             dist_init=dist_temp
 109             xj_temp=xj
 110             yj_temp=yj
 111             zj_temp=zj
 112             isubchap=1
 113           endif
 114        enddo
 115        enddo
 116        enddo
 117        if (isubchap.eq.1) then
 118           xj=xj_temp-xmedi
 119           yj=yj_temp-ymedi
 120           zj=zj_temp-zmedi
 121        else
 122           xj=xj_safe-xmedi
 123           yj=yj_safe-ymedi
 124           zj=zj_safe-zmedi
 125        endif
 126           rij=xj*xj+yj*yj+zj*zj
 127             sss=sscale(sqrt(rij))
 128             sssgrad=sscagrad(sqrt(rij))
 129           rrmij=1.0/(xj*xj+yj*yj+zj*zj)
 130           rmij=sqrt(rrmij)
 131           r3ij=rrmij*rmij
 132           r6ij=r3ij*r3ij
 133           vrmij=vblinv*rmij
 134           cosa=(dxi*dxj+dyi*dyj+dzi*dzj)*vblinv2
 135           cosb=(xj*dxi+yj*dyi+zj*dzi)*vrmij
 136           cosg=(xj*dxj+yj*dyj+zj*dzj)*vrmij
 137           fac=cosa-3.0*cosb*cosg
 138           ev1=aaa*r6ij*r6ij
 139           ev2=bbb*r6ij
 140           fac3=ael6i*r6ij
 141           fac4=ael3i*r3ij
 142           evdwij=ev1+ev2
 143           el1=fac3*(4.0+fac*fac-3.0*(cosb*cosb+cosg*cosg))
 144           el2=fac4*fac
 145           eesij=el1+el2
 146           if (j.gt.i+2 .and. eesij.le.elcutoff .or.
 147      &        j.eq.i+2 .and. eesij.le.elecutoff_14) then
 148              ncont=ncont+1
 149              icont(1,ncont)=i
 150              icont(2,ncont)=j
 151              econt(ncont)=eesij
 152           endif
 153           ees=ees+eesij
 154           evdw=evdw+evdwij*sss
 155     4   continue
 156     1 continue
 157       if (lprint) then
 158         write (iout,*) 'Total average electrostatic energy: ',ees
 159         write (iout,*) 'VDW energy between peptide-group centers: ',evdw
 160         write (iout,*)
 161         write (iout,*) 'Electrostatic contacts before pruning: '
 162         do i=1,ncont
 163           i1=icont(1,i)
 164           i2=icont(2,i)
 165           it1=itype(i1)
 166           it2=itype(i2)
 167           write (iout,'(i3,2x,a,i4,2x,a,i4,f10.5)')
 168      &     i,restyp(it1),i1,restyp(it2),i2,econt(i)
 169         enddo
 170       endif
 171 c For given residues keep only the contacts with the greatest energy.
 172       i=0
 173       do while (i.lt.ncont)
 174         i=i+1
 175         ene=econt(i)
 176         ic1=icont(1,i)
 177         ic2=icont(2,i)
 178         j=i
 179         do while (j.lt.ncont)
 180           j=j+1
 181           if (ic1.eq.icont(1,j).and.iabs(icont(2,j)-ic2).le.2 .or.
 182      &        ic2.eq.icont(2,j).and.iabs(icont(1,j)-ic1).le.2) then
 183 c            write (iout,*) "i",i," j",j," ic1",ic1," ic2",ic2,
 184 c     &       " jc1",icont(1,j)," jc2",icont(2,j)," ncont",ncont
 185             if (econt(j).lt.ene .and. icont(2,j).ne.icont(1,j)+2) then
 186               if (ic1.eq.icont(1,j)) then
 187                 do k=1,ncont
 188                   if (k.ne.i .and. k.ne.j .and. icont(2,k).eq.icont(2,j)
 189      &               .and. iabs(icont(1,k)-ic1).le.2 .and.
 190      &               econt(k).lt.econt(j) ) goto 21
 191                 enddo
 192               else if (ic2.eq.icont(2,j) ) then
 193                 do k=1,ncont
 194                   if (k.ne.i .and. k.ne.j .and. icont(1,k).eq.icont(1,j)
 195      &               .and. iabs(icont(2,k)-ic2).le.2 .and.
 196      &               econt(k).lt.econt(j) ) goto 21
 197                 enddo
 198               endif
 199 c Remove ith contact
 200               do k=i+1,ncont
 201                 icont(1,k-1)=icont(1,k)
 202                 icont(2,k-1)=icont(2,k)
 203                 econt(k-1)=econt(k)
 204               enddo
 205               i=i-1
 206               ncont=ncont-1
 207 c              write (iout,*) "ncont",ncont
 208 c              do k=1,ncont
 209 c                write (iout,*) icont(1,k),icont(2,k)
 210 c              enddo
 211               goto 20
 212             else if (econt(j).gt.ene .and. ic2.ne.ic1+2)
 213      &      then
 214               if (ic1.eq.icont(1,j)) then
 215                 do k=1,ncont
 216                   if (k.ne.i .and. k.ne.j .and. icont(2,k).eq.ic2
 217      &               .and. iabs(icont(1,k)-icont(1,j)).le.2 .and.
 218      &               econt(k).lt.econt(i) ) goto 21
 219                 enddo
 220               else if (ic2.eq.icont(2,j) ) then
 221                 do k=1,ncont
 222                   if (k.ne.i .and. k.ne.j .and. icont(1,k).eq.ic1
 223      &               .and. iabs(icont(2,k)-icont(2,j)).le.2 .and.
 224      &               econt(k).lt.econt(i) ) goto 21
 225                 enddo
 226               endif
 227 c Remove jth contact
 228               do k=j+1,ncont
 229                 icont(1,k-1)=icont(1,k)
 230                 icont(2,k-1)=icont(2,k)
 231                 econt(k-1)=econt(k)
 232               enddo
 233               ncont=ncont-1
 234 c              write (iout,*) "ncont",ncont
 235 c              do k=1,ncont
 236 c                write (iout,*) icont(1,k),icont(2,k)
 237 c              enddo
 238               j=j-1
 239             endif
 240           endif
 241    21     continue
 242         enddo
 243    20   continue
 244       enddo
 245       if (lprint) then
 246         write (iout,*)
 247         write (iout,*) 'Electrostatic contacts after pruning: '
 248         do i=1,ncont
 249           i1=icont(1,i)
 250           i2=icont(2,i)
 251           it1=itype(i1)
 252           it2=itype(i2)
 253           write (iout,'(i3,2x,a,i4,2x,a,i4,f10.5)')
 254      &     i,restyp(it1),i1,restyp(it2),i2,econt(i)
 255         enddo
 256       endif
 257       return
 258       end