Adding dyn_ss and triss potentials to src-M wham
authorAdam Sieradzan <adasko@piasek4.chem.univ.gda.pl>
Fri, 22 May 2015 21:24:45 +0000 (23:24 +0200)
committerAdam Sieradzan <adasko@piasek4.chem.univ.gda.pl>
Fri, 22 May 2015 21:24:45 +0000 (23:24 +0200)
source/wham/src-M/CMakeLists.txt
source/wham/src-M/cxread.F
source/wham/src-M/enecalc1.F
source/wham/src-M/energy_p_new.F
source/wham/src-M/geomout.F
source/wham/src-M/include_unres/COMMON.SBRIDGE
source/wham/src-M/initialize_p.F
source/wham/src-M/molread_zs.F
source/wham/src-M/parmread.F
source/wham/src-M/ssMD.F [new file with mode: 0644]

index 3228a13..678a85f 100644 (file)
@@ -61,6 +61,7 @@ set(UNRES_WHAM_M_SRC0
        proc_cont.f
        define_pairs.f
        mysort.f
+        ssMD.F
 )
 
 set(UNRES_WHAM_M_PP_SRC
index 7bb2f6a..e29fb24 100644 (file)
@@ -63,8 +63,13 @@ c      write (iout,*) "rpotE",rpotE," iret",iret
       call xdrffloat_(ixdrf, rt_bath, iret)
       call xdrfint_(ixdrf, nss, iret)
       do j=1,nss
-        call xdrfint_(ixdrf, ihpb(j), iret)
-        call xdrfint_(ixdrf, jhpb(j), iret)
+           if (dyn_ss) then
+            call xdrfint(ixdrf, idssb(j)+nres, iret)
+            call xdrfint(ixdrf, jdssb(j)+nres, iret)
+           else
+            call xdrfint_(ixdrf, ihpb(j), iret)
+            call xdrfint_(ixdrf, jhpb(j), iret)
+           endif
       enddo
       call xdrfint_(ixdrf, nprop, iret)
       if (umbrella(iparm) .or. read_iset(iparm) .or. hamil_rep) 
@@ -81,8 +86,13 @@ c      write (iout,*) "rpotE",rpotE," iret",iret
       call xdrffloat(ixdrf, rt_bath, iret)
       call xdrfint(ixdrf, nss, iret)
       do j=1,nss
-        call xdrfint(ixdrf, ihpb(j), iret)
-        call xdrfint(ixdrf, jhpb(j), iret)
+           if (dyn_ss) then
+            call xdrfint(ixdrf, idssb(j)+nres, iret)
+            call xdrfint(ixdrf, jdssb(j)+nres, iret)
+           else
+            call xdrfint(ixdrf, ihpb(j), iret)
+            call xdrfint(ixdrf, jhpb(j), iret)
+           endif
       enddo
       call xdrfint(ixdrf, nprop, iret)
 c      write (iout,*) "nprop",nprop
index 16ae771..e36aa27 100644 (file)
@@ -669,8 +669,13 @@ c      write (iout,*) "xdrf3dfcoord"
 c      call flush(iout)
       call xdrfint_(ixdrf, nss, iret)
       do j=1,nss
-        call xdrfint_(ixdrf, ihpb(j), iret)
-        call xdrfint_(ixdrf, jhpb(j), iret)
+           if (dyn_ss) then
+            call xdrfint(ixdrf, idssb(j)+nres, iret)
+            call xdrfint(ixdrf, jdssb(j)+nres, iret)
+           else
+            call xdrfint_(ixdrf, ihpb(j), iret)
+            call xdrfint_(ixdrf, jhpb(j), iret)
+           endif
       enddo
       call xdrffloat_(ixdrf,real(eini),iret) 
       call xdrffloat_(ixdrf,real(efree),iret) 
@@ -681,8 +686,13 @@ c      call flush(iout)
 
       call xdrfint(ixdrf, nss, iret)
       do j=1,nss
-        call xdrfint(ixdrf, ihpb(j), iret)
-        call xdrfint(ixdrf, jhpb(j), iret)
+           if (dyn_ss) then
+            call xdrfint(ixdrf, idssb(j)+nres, iret)
+            call xdrfint(ixdrf, jdssb(j)+nres, iret)
+           else
+            call xdrfint(ixdrf, ihpb(j), iret)
+            call xdrfint(ixdrf, jhpb(j), iret)
+           endif
       enddo
       call xdrffloat(ixdrf,real(eini),iret) 
       call xdrffloat(ixdrf,real(efree),iret) 
index 413817c..09244ec 100644 (file)
@@ -232,6 +232,7 @@ c     &   +wsccor*fact(1)*gsccor_loc(i)
 c BYLA ROZNICA Z CLUSTER< OSTATNIA LINIA DODANA
       enddo
       endif
+      if (dyn_ss) call dyn_set_nss
       return
       end
 C------------------------------------------------------------------------
@@ -783,6 +784,7 @@ C
       include 'COMMON.ENEPS'
       include 'COMMON.IOUNITS'
       include 'COMMON.CALC'
+      include 'COMMON.SBRIDGE'
       logical lprn
       common /srutu/icall
       integer icant
@@ -814,6 +816,26 @@ C Calculate SC interaction energy.
 C
         do iint=1,nint_gr(i)
           do j=istart(i,iint),iend(i,iint)
+            IF (dyn_ss_mask(i).and.dyn_ss_mask(j)) THEN
+              call dyn_ssbond_ene(i,j,evdwij)
+              evdw=evdw+evdwij
+C              if (energy_dec) write (iout,'(a6,2i5,0pf7.3,a3)')
+C     &                        'evdw',i,j,evdwij,' ss'
+C triple bond artifac removal
+             do k=j+1,iend(i,iint)
+C search over all next residues
+              if (dyn_ss_mask(k)) then
+C check if they are cysteins
+C              write(iout,*) 'k=',k
+              call triple_ssbond_ene(i,j,k,evdwij)
+C call the energy function that removes the artifical triple disulfide
+C bond the soubroutine is located in ssMD.F
+              evdw=evdw+evdwij
+C              if (energy_dec) write (iout,'(a6,2i5,0pf7.3,a3)')
+C     &                        'evdw',i,j,evdwij,'tss'
+              endif!dyn_ss_mask(k)
+             enddo! k
+            ELSE
             ind=ind+1
             itypj=iabs(itype(j))
             if (itypj.eq.ntyp1) cycle
@@ -907,6 +929,7 @@ C Calculate the radial part of the gradient
 C Calculate angular part of the gradient.
             call sc_grad
             endif
+            ENDIF    ! dyn_ss            
           enddo      ! j
         enddo        ! iint
       enddo          ! i
@@ -2943,10 +2966,15 @@ C iii and jjj point to the residues for which the distance is assigned.
         endif
 C 24/11/03 AL: SS bridges handled separately because of introducing a specific
 C    distance and angle dependent SS bond potential.
-        if (ii.gt.nres .and. iabs(itype(iii)).eq.1 .and. 
+C        if (ii.gt.nres .and. iabs(itype(iii)).eq.1 .and. 
+C     & iabs(itype(jjj)).eq.1) then
+
+       if (.not.dyn_ss .and. i.le.nss) then
+         if (ii.gt.nres .and. iabs(itype(iii)).eq.1 .and.
      & iabs(itype(jjj)).eq.1) then
           call ssbond_ene(iii,jjj,eij)
           ehpb=ehpb+2*eij
+           endif
         else
 C Calculate the distance between the two points and its difference from the
 C target distance.
index 0f729e4..c9110ae 100644 (file)
         write (ipdb,30) ica(nct),ica(nct)+1
       endif
       do i=1,nss
+       if (dyn_ss) then
+        write (iunit,30) ica(idssb(i))+1,ica(jdssb(i))+1
+       else
         write (ipdb,30) ica(ihpb(i)-nres)+1,ica(jhpb(i)-nres)+1
+       endif
       enddo
       write (ipdb,'(a6)') 'ENDMDL'
   10  FORMAT ('ATOM',I7,'  CA  ',A3,1X,A1,I4,4X,3F8.3,f15.3)
@@ -105,7 +109,18 @@ C format.
         write (imol2,'(i5,2i6,i2)') i-nnt+1,i-nnt+1,i-nnt+2,1
       enddo
       do i=1,nss
-        write (imol2,'(i5,2i6,i2)') nct-nnt+i,ihpb(i),jhpb(i),1
+C        write (imol2,'(i5,2i6,i2)') nct-nnt+i,ihpb(i),jhpb(i),1
+         if (dyn_ss) then
+          write(imol2,'(a6,i4,1x,a3,i7,4x,a3,i7)') 
+     &         'SSBOND',i,'CYS',ihpb(i)-1-nres,
+     &                    'CYS',jhpb(i)-1-nres
+C     &         'SSBOND',i,'CYS',idssb(i)-nnt+1,
+C     &                    'CYS',jdssb(i)-nnt+1
+         else
+          write(imol2,'(a6,i4,1x,a3,i7,4x,a3,i7)') 
+     &         'SSBOND',i,'CYS',ihpb(i)-nnt+1-nres,
+     &                    'CYS',jhpb(i)-nnt+1-nres
+         endif
       enddo
       write (imol2,'(a)') '\@<TRIPOS>SUBSTRUCTURE'
       do i=nnt,nct
index 5c87412..144a864 100644 (file)
@@ -1,9 +1,18 @@
-      double precision ebr,d0cm,akcm,akth,akct,v1ss,v2ss,v3ss,dhpb,
-     & forcon,weidis
-      integer ns,nss,nfree,iss,ihpb,jhpb,nhpb,link_start,link_end
-      common /sbridge/ ebr,d0cm,akcm,akth,akct,v1ss,v2ss,v3ss,ns,nss,
-     &  nfree,iss(maxss)
-      common /links/ dhpb(maxdim),forcon(maxdim),ihpb(maxdim),
-     & jhpb(maxdim),nhpb
+      double precision ss_depth,ebr,d0cm,akcm,akth,akct,v1ss,v2ss,v3ss
+      integer ns,nss,nfree,iss
+      common /sbridge/ ss_depth,ebr,d0cm,akcm,akth,akct,v1ss,v2ss,v3ss,
+     & ns,nss,nfree,iss(maxss)
+      double precision dhpb,dhpb1,forcon
+      integer ihpb,jhpb,nhpb,idssb,jdssb
+      common /links/ dhpb(maxdim),dhpb1(maxdim),forcon(maxdim),
+     & ihpb(maxdim),jhpb(maxdim),nhpb
+      double precision weidis
       common /restraints/ weidis
+      integer link_start,link_end
       common /links_split/ link_start,link_end
+      double precision Ht,dyn_ssbond_ij,dtriss,atriss,btriss,ctriss
+      logical dyn_ss,dyn_ss_mask
+      common /dyn_ssbond/ dtriss,atriss,btriss,ctriss,
+     &  dyn_ssbond_ij(maxres,maxres),
+     &  idssb(maxdim),jdssb(maxdim),
+     &  Ht,dyn_ss,dyn_ss_mask(maxres)
index 9d159a9..0dd08c0 100644 (file)
@@ -328,6 +328,7 @@ cd    write (iout,*) 'ns=',ns,' nss=',nss,' ihpb,jhpb',
 cd   &   (ihpb(i),jhpb(i),i=1,nss)
       do i=nnt,nct-1
         scheck=.false.
+        if (dyn_ss) goto 10
         do ii=1,nss
           if (ihpb(ii).eq.i+nres) then
             scheck=.true.
index 3e09be5..4462f2d 100644 (file)
@@ -104,6 +104,9 @@ C Convert sequence to numeric code
         write (iout,'(/a,i3,a)') 'The chain contains',ns,
      &  ' disulfide-bridging cysteines.'
         write (iout,'(20i4)') (iss(i),i=1,ns)
+       if (dyn_ss) then
+          write(iout,*)"Running with dynamic disulfide-bond formation"
+       else
         write (iout,'(/a/)') 'Pre-formed links are:' 
         do i=1,nss
          i1=ihpb(i)-nres
@@ -115,7 +118,22 @@ C Convert sequence to numeric code
      &    dhpb(i),ebr,forcon(i)
         enddo
       endif
+      endif
       write (iout,'(a)')
+      if (ns.gt.0.and.dyn_ss) then
+          do i=nss+1,nhpb
+            ihpb(i-nss)=ihpb(i)
+            jhpb(i-nss)=jhpb(i)
+            forcon(i-nss)=forcon(i)
+            dhpb(i-nss)=dhpb(i)
+          enddo
+          nhpb=nhpb-nss
+          nss=0
+          call hpb_partition
+          do i=1,ns
+            dyn_ss_mask(iss(i))=.true.
+          enddo
+      endif
       return
       end
 c-----------------------------------------------------------------------------
@@ -154,10 +172,12 @@ C Check whether the specified bridging residues are cystines.
       do i=1,ns
        if (itype(iss(i)).ne.1) then
          write (iout,'(2a,i3,a)') 
-     &   'Do you REALLY think that the residue ',restyp(iss(i)),i,
+     &   'Do you REALLY think that the residue ',
+     &    restyp(itype(iss(i))),i,
      &   ' can form a disulfide bridge?!!!'
          write (*,'(2a,i3,a)') 
-     &   'Do you REALLY think that the residue ',restyp(iss(i)),i,
+     &   'Do you REALLY think that the residue ',
+     &    restyp(itype(iss(i))),i,
      &   ' can form a disulfide bridge?!!!'
          stop
         endif
index c9ac2a3..9633858 100644 (file)
@@ -55,6 +55,32 @@ C Assign virtual-bond length
 
       write (iout,*) "iparm",iparm," myparm",myparm
 c If reading not own parameters, skip assignment
+      call reada(controlcard,"DTRISS",dtriss,1.0D0)
+      call reada(controlcard,"ATRISS",atriss,0.3D0)
+      call reada(controlcard,"BTRISS",btriss,0.02D0)
+      call reada(controlcard,"CTRISS",ctriss,1.0D0)
+      dyn_ss=(index(controlcard,'DYN_SS').gt.0)
+      do i=1,maxres
+        dyn_ss_mask(i)=.false.
+      enddo
+      do i=1,maxres-1
+        do j=i+1,maxres
+          dyn_ssbond_ij(i,j)=1.0d300
+        enddo
+      enddo
+      call reada(controlcard,"HT",Ht,0.0D0)
+      if (dyn_ss) then
+        ss_depth=ebr/wsc-0.25*eps(1,1)
+        Ht=Ht/wsc-0.25*eps(1,1)
+        akcm=akcm*wstrain/wsc
+        akth=akth*wstrain/wsc
+        akct=akct*wstrain/wsc
+        v1ss=v1ss*wstrain/wsc
+        v2ss=v2ss*wstrain/wsc
+        v3ss=v3ss*wstrain/wsc
+      else
+        ss_depth=ebr/wstrain-0.25*eps(1,1)*wsc/wstrain
+      endif
 
       if (iparm.eq.myparm .or. .not.separate_parset) then
 
diff --git a/source/wham/src-M/ssMD.F b/source/wham/src-M/ssMD.F
new file mode 100644 (file)
index 0000000..283adf3
--- /dev/null
@@ -0,0 +1,2099 @@
+c----------------------------------------------------------------------------
+      subroutine check_energies
+c      implicit none
+
+c     Includes
+      include 'DIMENSIONS'
+      include 'COMMON.CHAIN'
+      include 'COMMON.VAR'
+      include 'COMMON.IOUNITS'
+      include 'COMMON.SBRIDGE'
+      include 'COMMON.LOCAL'
+      include 'COMMON.GEO'
+
+c     External functions
+      double precision ran_number
+      external ran_number
+
+c     Local variables
+      integer i,j,k,l,lmax,p,pmax
+      double precision rmin,rmax
+      double precision eij
+
+      double precision d
+      double precision wi,rij,tj,pj
+
+
+c      return
+
+      i=5
+      j=14
+
+      d=dsc(1)
+      rmin=2.0D0
+      rmax=12.0D0
+
+      lmax=10000
+      pmax=1
+
+      do k=1,3
+        c(k,i)=0.0D0
+        c(k,j)=0.0D0
+        c(k,nres+i)=0.0D0
+        c(k,nres+j)=0.0D0
+      enddo
+
+      do l=1,lmax
+
+ct        wi=ran_number(0.0D0,pi)
+c        wi=ran_number(0.0D0,pi/6.0D0)
+c        wi=0.0D0
+ct        tj=ran_number(0.0D0,pi)
+ct        pj=ran_number(0.0D0,pi)
+c        pj=ran_number(0.0D0,pi/6.0D0)
+c        pj=0.0D0
+
+        do p=1,pmax
+ct           rij=ran_number(rmin,rmax)
+
+           c(1,j)=d*sin(pj)*cos(tj)
+           c(2,j)=d*sin(pj)*sin(tj)
+           c(3,j)=d*cos(pj)
+
+           c(3,nres+i)=-rij
+
+           c(1,i)=d*sin(wi)
+           c(3,i)=-rij-d*cos(wi)
+
+           do k=1,3
+              dc(k,nres+i)=c(k,nres+i)-c(k,i)
+              dc_norm(k,nres+i)=dc(k,nres+i)/d
+              dc(k,nres+j)=c(k,nres+j)-c(k,j)
+              dc_norm(k,nres+j)=dc(k,nres+j)/d
+           enddo
+
+           call dyn_ssbond_ene(i,j,eij)
+        enddo
+      enddo
+
+      call exit(1)
+
+      return
+      end
+
+C-----------------------------------------------------------------------------
+
+      subroutine dyn_ssbond_ene(resi,resj,eij)
+c      implicit none
+
+c     Includes
+      include 'DIMENSIONS'
+      include 'COMMON.SBRIDGE'
+      include 'COMMON.CHAIN'
+      include 'COMMON.DERIV'
+      include 'COMMON.LOCAL'
+      include 'COMMON.INTERACT'
+      include 'COMMON.VAR'
+      include 'COMMON.IOUNITS'
+      include 'COMMON.CALC'
+#ifndef CLUST
+#ifndef WHAM
+C      include 'COMMON.MD'
+#endif
+#endif
+
+c     External functions
+      double precision h_base
+      external h_base
+
+c     Input arguments
+      integer resi,resj
+
+c     Output arguments
+      double precision eij
+
+c     Local variables
+      logical havebond
+c      integer itypi,itypj,k,l
+      double precision rrij,ssd,deltat1,deltat2,deltat12,cosphi
+      double precision sig0ij,ljd,sig,fac,e1,e2
+      double precision dcosom1(3),dcosom2(3),ed
+      double precision pom1,pom2
+      double precision ljA,ljB,ljXs
+      double precision d_ljB(1:3)
+      double precision ssA,ssB,ssC,ssXs
+      double precision ssxm,ljxm,ssm,ljm
+      double precision d_ssxm(1:3),d_ljxm(1:3),d_ssm(1:3),d_ljm(1:3)
+      double precision f1,f2,h1,h2,hd1,hd2
+      double precision omega,delta_inv,deltasq_inv,fac1,fac2
+c-------FIRST METHOD
+      double precision xm,d_xm(1:3)
+c-------END FIRST METHOD
+c-------SECOND METHOD
+c$$$      double precision ss,d_ss(0:3),ljf,d_ljf(0:3)
+c-------END SECOND METHOD
+
+c-------TESTING CODE
+      logical checkstop,transgrad
+      common /sschecks/ checkstop,transgrad
+
+      integer icheck,nicheck,jcheck,njcheck
+      double precision echeck(-1:1),deps,ssx0,ljx0
+c-------END TESTING CODE
+
+
+      i=resi
+      j=resj
+
+      itypi=itype(i)
+      dxi=dc_norm(1,nres+i)
+      dyi=dc_norm(2,nres+i)
+      dzi=dc_norm(3,nres+i)
+      dsci_inv=vbld_inv(i+nres)
+
+      itypj=itype(j)
+      xj=c(1,nres+j)-c(1,nres+i)
+      yj=c(2,nres+j)-c(2,nres+i)
+      zj=c(3,nres+j)-c(3,nres+i)
+      dxj=dc_norm(1,nres+j)
+      dyj=dc_norm(2,nres+j)
+      dzj=dc_norm(3,nres+j)
+      dscj_inv=vbld_inv(j+nres)
+
+      chi1=chi(itypi,itypj)
+      chi2=chi(itypj,itypi)
+      chi12=chi1*chi2
+      chip1=chip(itypi)
+      chip2=chip(itypj)
+      chip12=chip1*chip2
+      alf1=alp(itypi)
+      alf2=alp(itypj)
+      alf12=0.5D0*(alf1+alf2)
+
+      rrij=1.0D0/(xj*xj+yj*yj+zj*zj)
+      rij=dsqrt(rrij)  ! sc_angular needs rij to really be the inverse
+c     The following are set in sc_angular
+c      erij(1)=xj*rij
+c      erij(2)=yj*rij
+c      erij(3)=zj*rij
+c      om1=dxi*erij(1)+dyi*erij(2)+dzi*erij(3)
+c      om2=dxj*erij(1)+dyj*erij(2)+dzj*erij(3)
+c      om12=dxi*dxj+dyi*dyj+dzi*dzj
+      call sc_angular
+      rij=1.0D0/rij  ! Reset this so it makes sense
+
+      sig0ij=sigma(itypi,itypj)
+      sig=sig0ij*dsqrt(1.0D0/sigsq)
+
+      ljXs=sig-sig0ij
+      ljA=eps1*eps2rt**2*eps3rt**2
+      ljB=ljA*bb(itypi,itypj)
+      ljA=ljA*aa(itypi,itypj)
+      ljxm=ljXs+(-2.0D0*aa(itypi,itypj)/bb(itypi,itypj))**(1.0D0/6.0D0)
+
+      ssXs=d0cm
+      deltat1=1.0d0-om1
+      deltat2=1.0d0+om2
+      deltat12=om2-om1+2.0d0
+      cosphi=om12-om1*om2
+      ssA=akcm
+      ssB=akct*deltat12
+      ssC=ss_depth
+     &     +akth*(deltat1*deltat1+deltat2*deltat2)
+     &     +v1ss*cosphi+v2ss*cosphi*cosphi+v3ss*cosphi*cosphi*cosphi
+      ssxm=ssXs-0.5D0*ssB/ssA
+
+c-------TESTING CODE
+c$$$c     Some extra output
+c$$$      ssm=ssC-0.25D0*ssB*ssB/ssA
+c$$$      ljm=-0.25D0*ljB*bb(itypi,itypj)/aa(itypi,itypj)
+c$$$      ssx0=ssB*ssB-4.0d0*ssA*ssC
+c$$$      if (ssx0.gt.0.0d0) then
+c$$$        ssx0=ssXs+0.5d0*(-ssB+sqrt(ssx0))/ssA
+c$$$      else
+c$$$        ssx0=ssxm
+c$$$      endif
+c$$$      ljx0=ljXs+(-aa(itypi,itypj)/bb(itypi,itypj))**(1.0D0/6.0D0)
+c$$$      write(iout,'(a,4f8.2,2f15.2,3f6.2)')"SSENERGIES ",
+c$$$     &     ssxm,ljxm,ssx0,ljx0,ssm,ljm,om1,om2,om12
+c$$$      return
+c-------END TESTING CODE
+
+c-------TESTING CODE
+c     Stop and plot energy and derivative as a function of distance
+      if (checkstop) then
+        ssm=ssC-0.25D0*ssB*ssB/ssA
+        ljm=-0.25D0*ljB*bb(itypi,itypj)/aa(itypi,itypj)
+        if (ssm.lt.ljm .and.
+     &       dabs(rij-0.5d0*(ssxm+ljxm)).lt.0.35d0*(ljxm-ssxm)) then
+          nicheck=1000
+          njcheck=1
+          deps=0.5d-7
+        else
+          checkstop=.false.
+        endif
+      endif
+      if (.not.checkstop) then
+        nicheck=0
+        njcheck=-1
+      endif
+
+      do icheck=0,nicheck
+      do jcheck=-1,njcheck
+      if (checkstop) rij=(ssxm-1.0d0)+
+     &       ((ljxm-ssxm+2.0d0)*icheck)/nicheck+jcheck*deps
+c-------END TESTING CODE
+
+      if (rij.gt.ljxm) then
+        havebond=.false.
+        ljd=rij-ljXs
+        fac=(1.0D0/ljd)**expon
+        e1=fac*fac*aa(itypi,itypj)
+        e2=fac*bb(itypi,itypj)
+        eij=eps1*eps2rt*eps3rt*(e1+e2)
+        eps2der=eij*eps3rt
+        eps3der=eij*eps2rt
+        eij=eij*eps2rt*eps3rt
+
+        sigder=-sig/sigsq
+        e1=e1*eps1*eps2rt**2*eps3rt**2
+        ed=-expon*(e1+eij)/ljd
+        sigder=ed*sigder
+        eom1=eps2der*eps2rt_om1-2.0D0*alf1*eps3der+sigder*sigsq_om1
+        eom2=eps2der*eps2rt_om2+2.0D0*alf2*eps3der+sigder*sigsq_om2
+        eom12=eij*eps1_om12+eps2der*eps2rt_om12
+     &       -2.0D0*alf12*eps3der+sigder*sigsq_om12
+      else if (rij.lt.ssxm) then
+        havebond=.true.
+        ssd=rij-ssXs
+        eij=ssA*ssd*ssd+ssB*ssd+ssC
+
+        ed=2*akcm*ssd+akct*deltat12
+        pom1=akct*ssd
+        pom2=v1ss+2*v2ss*cosphi+3*v3ss*cosphi*cosphi
+        eom1=-2*akth*deltat1-pom1-om2*pom2
+        eom2= 2*akth*deltat2+pom1-om1*pom2
+        eom12=pom2
+      else
+        omega=v1ss+2.0d0*v2ss*cosphi+3.0d0*v3ss*cosphi*cosphi
+
+        d_ssxm(1)=0.5D0*akct/ssA
+        d_ssxm(2)=-d_ssxm(1)
+        d_ssxm(3)=0.0D0
+
+        d_ljxm(1)=sig0ij/sqrt(sigsq**3)
+        d_ljxm(2)=d_ljxm(1)*sigsq_om2
+        d_ljxm(3)=d_ljxm(1)*sigsq_om12
+        d_ljxm(1)=d_ljxm(1)*sigsq_om1
+
+c-------FIRST METHOD, DISCONTINUOUS SECOND DERIVATIVE
+        xm=0.5d0*(ssxm+ljxm)
+        do k=1,3
+          d_xm(k)=0.5d0*(d_ssxm(k)+d_ljxm(k))
+        enddo
+        if (rij.lt.xm) then
+          havebond=.true.
+          ssm=ssC-0.25D0*ssB*ssB/ssA
+          d_ssm(1)=0.5D0*akct*ssB/ssA
+          d_ssm(2)=2.0D0*akth*deltat2-om1*omega-d_ssm(1)
+          d_ssm(1)=-2.0D0*akth*deltat1-om2*omega+d_ssm(1)
+          d_ssm(3)=omega
+          f1=(rij-xm)/(ssxm-xm)
+          f2=(rij-ssxm)/(xm-ssxm)
+          h1=h_base(f1,hd1)
+          h2=h_base(f2,hd2)
+          eij=ssm*h1+Ht*h2
+          delta_inv=1.0d0/(xm-ssxm)
+          deltasq_inv=delta_inv*delta_inv
+          fac=ssm*hd1-Ht*hd2
+          fac1=deltasq_inv*fac*(xm-rij)
+          fac2=deltasq_inv*fac*(rij-ssxm)
+          ed=delta_inv*(Ht*hd2-ssm*hd1)
+          eom1=fac1*d_ssxm(1)+fac2*d_xm(1)+h1*d_ssm(1)
+          eom2=fac1*d_ssxm(2)+fac2*d_xm(2)+h1*d_ssm(2)
+          eom12=fac1*d_ssxm(3)+fac2*d_xm(3)+h1*d_ssm(3)
+        else
+          havebond=.false.
+          ljm=-0.25D0*ljB*bb(itypi,itypj)/aa(itypi,itypj)
+          d_ljm(1)=-0.5D0*bb(itypi,itypj)/aa(itypi,itypj)*ljB
+          d_ljm(2)=d_ljm(1)*(0.5D0*eps2rt_om2/eps2rt+alf2/eps3rt)
+          d_ljm(3)=d_ljm(1)*(0.5D0*eps1_om12+0.5D0*eps2rt_om12/eps2rt-
+     +         alf12/eps3rt)
+          d_ljm(1)=d_ljm(1)*(0.5D0*eps2rt_om1/eps2rt-alf1/eps3rt)
+          f1=(rij-ljxm)/(xm-ljxm)
+          f2=(rij-xm)/(ljxm-xm)
+          h1=h_base(f1,hd1)
+          h2=h_base(f2,hd2)
+          eij=Ht*h1+ljm*h2
+          delta_inv=1.0d0/(ljxm-xm)
+          deltasq_inv=delta_inv*delta_inv
+          fac=Ht*hd1-ljm*hd2
+          fac1=deltasq_inv*fac*(ljxm-rij)
+          fac2=deltasq_inv*fac*(rij-xm)
+          ed=delta_inv*(ljm*hd2-Ht*hd1)
+          eom1=fac1*d_xm(1)+fac2*d_ljxm(1)+h2*d_ljm(1)
+          eom2=fac1*d_xm(2)+fac2*d_ljxm(2)+h2*d_ljm(2)
+          eom12=fac1*d_xm(3)+fac2*d_ljxm(3)+h2*d_ljm(3)
+        endif
+c-------END FIRST METHOD, DISCONTINUOUS SECOND DERIVATIVE
+
+c-------SECOND METHOD, CONTINUOUS SECOND DERIVATIVE
+c$$$        ssd=rij-ssXs
+c$$$        ljd=rij-ljXs
+c$$$        fac1=rij-ljxm
+c$$$        fac2=rij-ssxm
+c$$$
+c$$$        d_ljB(1)=ljB*(eps2rt_om1/eps2rt-2.0d0*alf1/eps3rt)
+c$$$        d_ljB(2)=ljB*(eps2rt_om2/eps2rt+2.0d0*alf2/eps3rt)
+c$$$        d_ljB(3)=ljB*(eps1_om12+eps2rt_om12/eps2rt-2.0d0*alf12/eps3rt)
+c$$$
+c$$$        ssm=ssC-0.25D0*ssB*ssB/ssA
+c$$$        d_ssm(1)=0.5D0*akct*ssB/ssA
+c$$$        d_ssm(2)=2.0D0*akth*deltat2-om1*omega-d_ssm(1)
+c$$$        d_ssm(1)=-2.0D0*akth*deltat1-om2*omega+d_ssm(1)
+c$$$        d_ssm(3)=omega
+c$$$
+c$$$        ljm=-0.25D0*bb(itypi,itypj)/aa(itypi,itypj)
+c$$$        do k=1,3
+c$$$          d_ljm(k)=ljm*d_ljB(k)
+c$$$        enddo
+c$$$        ljm=ljm*ljB
+c$$$
+c$$$        ss=ssA*ssd*ssd+ssB*ssd+ssC
+c$$$        d_ss(0)=2.0d0*ssA*ssd+ssB
+c$$$        d_ss(2)=akct*ssd
+c$$$        d_ss(1)=-d_ss(2)-2.0d0*akth*deltat1-om2*omega
+c$$$        d_ss(2)=d_ss(2)+2.0d0*akth*deltat2-om1*omega
+c$$$        d_ss(3)=omega
+c$$$
+c$$$        ljf=bb(itypi,itypj)/aa(itypi,itypj)
+c$$$        ljf=9.0d0*ljf*(-0.5d0*ljf)**(1.0d0/3.0d0)
+c$$$        d_ljf(0)=ljf*2.0d0*ljB*fac1
+c$$$        do k=1,3
+c$$$          d_ljf(k)=d_ljm(k)+ljf*(d_ljB(k)*fac1*fac1-
+c$$$     &         2.0d0*ljB*fac1*d_ljxm(k))
+c$$$        enddo
+c$$$        ljf=ljm+ljf*ljB*fac1*fac1
+c$$$
+c$$$        f1=(rij-ljxm)/(ssxm-ljxm)
+c$$$        f2=(rij-ssxm)/(ljxm-ssxm)
+c$$$        h1=h_base(f1,hd1)
+c$$$        h2=h_base(f2,hd2)
+c$$$        eij=ss*h1+ljf*h2
+c$$$        delta_inv=1.0d0/(ljxm-ssxm)
+c$$$        deltasq_inv=delta_inv*delta_inv
+c$$$        fac=ljf*hd2-ss*hd1
+c$$$        ed=d_ss(0)*h1+d_ljf(0)*h2+delta_inv*fac
+c$$$        eom1=d_ss(1)*h1+d_ljf(1)*h2+deltasq_inv*fac*
+c$$$     &       (fac1*d_ssxm(1)-fac2*(d_ljxm(1)))
+c$$$        eom2=d_ss(2)*h1+d_ljf(2)*h2+deltasq_inv*fac*
+c$$$     &       (fac1*d_ssxm(2)-fac2*(d_ljxm(2)))
+c$$$        eom12=d_ss(3)*h1+d_ljf(3)*h2+deltasq_inv*fac*
+c$$$     &       (fac1*d_ssxm(3)-fac2*(d_ljxm(3)))
+c$$$
+c$$$        havebond=.false.
+c$$$        if (ed.gt.0.0d0) havebond=.true.
+c-------END SECOND METHOD, CONTINUOUS SECOND DERIVATIVE
+
+      endif
+
+      if (havebond) then
+#ifndef CLUST
+#ifndef WHAM
+c        if (dyn_ssbond_ij(i,j).eq.1.0d300) then
+c          write(iout,'(a15,f12.2,f8.1,2i5)')
+c     &         "SSBOND_E_FORM",totT,t_bath,i,j
+c        endif
+#endif
+#endif
+        dyn_ssbond_ij(i,j)=eij
+      else if (.not.havebond .and. dyn_ssbond_ij(i,j).lt.1.0d300) then
+        dyn_ssbond_ij(i,j)=1.0d300
+#ifndef CLUST
+#ifndef WHAM
+c        write(iout,'(a15,f12.2,f8.1,2i5)')
+c     &       "SSBOND_E_BREAK",totT,t_bath,i,j
+#endif
+#endif
+      endif
+
+c-------TESTING CODE
+      if (checkstop) then
+        if (jcheck.eq.0) write(iout,'(a,3f15.8,$)')
+     &       "CHECKSTOP",rij,eij,ed
+        echeck(jcheck)=eij
+      endif
+      enddo
+      if (checkstop) then
+        write(iout,'(f15.8)')(echeck(1)-echeck(-1))*0.5d0/deps
+      endif
+      enddo
+      if (checkstop) then
+        transgrad=.true.
+        checkstop=.false.
+      endif
+c-------END TESTING CODE
+
+      do k=1,3
+        dcosom1(k)=(dc_norm(k,nres+i)-om1*erij(k))/rij
+        dcosom2(k)=(dc_norm(k,nres+j)-om2*erij(k))/rij
+      enddo
+      do k=1,3
+        gg(k)=ed*erij(k)+eom1*dcosom1(k)+eom2*dcosom2(k)
+      enddo
+      do k=1,3
+        gvdwx(k,i)=gvdwx(k,i)-gg(k)
+     &       +(eom12*(dc_norm(k,nres+j)-om12*dc_norm(k,nres+i))
+     &       +eom1*(erij(k)-om1*dc_norm(k,nres+i)))*dsci_inv
+        gvdwx(k,j)=gvdwx(k,j)+gg(k)
+     &       +(eom12*(dc_norm(k,nres+i)-om12*dc_norm(k,nres+j))
+     &       +eom2*(erij(k)-om2*dc_norm(k,nres+j)))*dscj_inv
+      enddo
+cgrad      do k=i,j-1
+cgrad        do l=1,3
+cgrad          gvdwc(l,k)=gvdwc(l,k)+gg(l)
+cgrad        enddo
+cgrad      enddo
+
+      do l=1,3
+        gvdwc(l,i)=gvdwc(l,i)-gg(l)
+        gvdwc(l,j)=gvdwc(l,j)+gg(l)
+      enddo
+
+      return
+      end
+
+C-----------------------------------------------------------------------------
+
+      double precision function h_base(x,deriv)
+c     A smooth function going 0->1 in range [0,1]
+c     It should NOT be called outside range [0,1], it will not work there.
+      implicit none
+
+c     Input arguments
+      double precision x
+
+c     Output arguments
+      double precision deriv
+
+c     Local variables
+      double precision xsq
+
+
+c     Two parabolas put together.  First derivative zero at extrema
+c$$$      if (x.lt.0.5D0) then
+c$$$        h_base=2.0D0*x*x
+c$$$        deriv=4.0D0*x
+c$$$      else
+c$$$        deriv=1.0D0-x
+c$$$        h_base=1.0D0-2.0D0*deriv*deriv
+c$$$        deriv=4.0D0*deriv
+c$$$      endif
+
+c     Third degree polynomial.  First derivative zero at extrema
+      h_base=x*x*(3.0d0-2.0d0*x)
+      deriv=6.0d0*x*(1.0d0-x)
+
+c     Fifth degree polynomial.  First and second derivatives zero at extrema
+c$$$      xsq=x*x
+c$$$      h_base=x*xsq*(6.0d0*xsq-15.0d0*x+10.0d0)
+c$$$      deriv=x-1.0d0
+c$$$      deriv=deriv*deriv
+c$$$      deriv=30.0d0*xsq*deriv
+
+      return
+      end
+
+c----------------------------------------------------------------------------
+
+      subroutine dyn_set_nss
+c     Adjust nss and other relevant variables based on dyn_ssbond_ij
+c      implicit none
+
+c     Includes
+      include 'DIMENSIONS'
+#ifdef MPI
+      include "mpif.h"
+#endif
+      include 'COMMON.SBRIDGE'
+      include 'COMMON.CHAIN'
+      include 'COMMON.IOUNITS'
+C      include 'COMMON.SETUP'
+#ifndef CLUST
+#ifndef WHAM
+C      include 'COMMON.MD'
+#endif
+#endif
+
+c     Local variables
+      double precision emin
+      integer i,j,imin
+      integer diff,allflag(maxdim),allnss,
+     &     allihpb(maxdim),alljhpb(maxdim),
+     &     newnss,newihpb(maxdim),newjhpb(maxdim)
+      logical found
+      integer i_newnss(1024),displ(0:1024)
+      integer g_newihpb(maxdim),g_newjhpb(maxdim),g_newnss
+
+      allnss=0
+      do i=1,nres-1
+        do j=i+1,nres
+          if (dyn_ssbond_ij(i,j).lt.1.0d300) then
+            allnss=allnss+1
+            allflag(allnss)=0
+            allihpb(allnss)=i
+            alljhpb(allnss)=j
+          endif
+        enddo
+      enddo
+
+cmc      write(iout,*)"ALLNSS ",allnss,(allihpb(i),alljhpb(i),i=1,allnss)
+
+ 1    emin=1.0d300
+      do i=1,allnss
+        if (allflag(i).eq.0 .and.
+     &       dyn_ssbond_ij(allihpb(i),alljhpb(i)).lt.emin) then
+          emin=dyn_ssbond_ij(allihpb(i),alljhpb(i))
+          imin=i
+        endif
+      enddo
+      if (emin.lt.1.0d300) then
+        allflag(imin)=1
+        do i=1,allnss
+          if (allflag(i).eq.0 .and.
+     &         (allihpb(i).eq.allihpb(imin) .or.
+     &         alljhpb(i).eq.allihpb(imin) .or.
+     &         allihpb(i).eq.alljhpb(imin) .or.
+     &         alljhpb(i).eq.alljhpb(imin))) then
+            allflag(i)=-1
+          endif
+        enddo
+        goto 1
+      endif
+
+cmc      write(iout,*)"ALLNSS ",allnss,(allihpb(i),alljhpb(i),i=1,allnss)
+
+      newnss=0
+      do i=1,allnss
+        if (allflag(i).eq.1) then
+          newnss=newnss+1
+          newihpb(newnss)=allihpb(i)
+          newjhpb(newnss)=alljhpb(i)
+        endif
+      enddo
+
+#ifdef MPI
+      if (nfgtasks.gt.1)then
+
+        call MPI_Reduce(newnss,g_newnss,1,
+     &    MPI_INTEGER,MPI_SUM,king,FG_COMM,IERR)
+        call MPI_Gather(newnss,1,MPI_INTEGER,
+     &                  i_newnss,1,MPI_INTEGER,king,FG_COMM,IERR)
+        displ(0)=0
+        do i=1,nfgtasks-1,1
+          displ(i)=i_newnss(i-1)+displ(i-1)
+        enddo
+        call MPI_Gatherv(newihpb,newnss,MPI_INTEGER,
+     &                   g_newihpb,i_newnss,displ,MPI_INTEGER,
+     &                   king,FG_COMM,IERR)     
+        call MPI_Gatherv(newjhpb,newnss,MPI_INTEGER,
+     &                   g_newjhpb,i_newnss,displ,MPI_INTEGER,
+     &                   king,FG_COMM,IERR)     
+        if(fg_rank.eq.0) then
+c         print *,'g_newnss',g_newnss
+c         print *,'g_newihpb',(g_newihpb(i),i=1,g_newnss)
+c         print *,'g_newjhpb',(g_newjhpb(i),i=1,g_newnss)
+         newnss=g_newnss  
+         do i=1,newnss
+          newihpb(i)=g_newihpb(i)
+          newjhpb(i)=g_newjhpb(i)
+         enddo
+        endif
+      endif
+#endif
+
+      diff=newnss-nss
+
+cmc      write(iout,*)"NEWNSS ",newnss,(newihpb(i),newjhpb(i),i=1,newnss)
+
+      do i=1,nss
+        found=.false.
+        do j=1,newnss
+          if (idssb(i).eq.newihpb(j) .and.
+     &         jdssb(i).eq.newjhpb(j)) found=.true.
+        enddo
+#ifndef CLUST
+#ifndef WHAM
+c        if (.not.found.and.fg_rank.eq.0) 
+c     &      write(iout,'(a15,f12.2,f8.1,2i5)')
+c     &       "SSBOND_BREAK",totT,t_bath,idssb(i),jdssb(i)
+#endif
+#endif
+      enddo
+
+      do i=1,newnss
+        found=.false.
+        do j=1,nss
+          if (newihpb(i).eq.idssb(j) .and.
+     &         newjhpb(i).eq.jdssb(j)) found=.true.
+        enddo
+#ifndef CLUST
+#ifndef WHAM
+c        if (.not.found.and.fg_rank.eq.0) 
+c     &      write(iout,'(a15,f12.2,f8.1,2i5)')
+c     &       "SSBOND_FORM",totT,t_bath,newihpb(i),newjhpb(i)
+#endif
+#endif
+      enddo
+
+      nss=newnss
+      do i=1,nss
+        idssb(i)=newihpb(i)
+        jdssb(i)=newjhpb(i)
+      enddo
+
+      return
+      end
+
+c----------------------------------------------------------------------------
+
+#ifdef WHAM
+      subroutine read_ssHist
+      implicit none
+
+c     Includes
+      include 'DIMENSIONS'
+      include "DIMENSIONS.FREE"
+      include 'COMMON.FREE'
+
+c     Local variables
+      integer i,j
+      character*80 controlcard
+
+      do i=1,dyn_nssHist
+        call card_concat(controlcard,.true.)
+        read(controlcard,*)
+     &       dyn_ssHist(i,0),(dyn_ssHist(i,j),j=1,2*dyn_ssHist(i,0))
+      enddo
+
+      return
+      end
+#endif
+
+c----------------------------------------------------------------------------
+
+
+C-----------------------------------------------------------------------------
+C-----------------------------------------------------------------------------
+C-----------------------------------------------------------------------------
+C-----------------------------------------------------------------------------
+C-----------------------------------------------------------------------------
+C-----------------------------------------------------------------------------
+C-----------------------------------------------------------------------------
+
+c$$$c-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine ss_relax(i_in,j_in)
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.INTERACT'
+c$$$
+c$$$c     Input arguments
+c$$$      integer i_in,j_in
+c$$$
+c$$$c     Local variables
+c$$$      integer i,iretcode,nfun_sc
+c$$$      logical scfail
+c$$$      double precision var(maxvar),e_sc,etot
+c$$$
+c$$$
+c$$$      mask_r=.true.
+c$$$      do i=nnt,nct
+c$$$        mask_side(i)=0
+c$$$      enddo
+c$$$      mask_side(i_in)=1
+c$$$      mask_side(j_in)=1
+c$$$
+c$$$c     Minimize the two selected side-chains
+c$$$      call overlap_sc(scfail)  ! Better not fail!
+c$$$      call minimize_sc(e_sc,var,iretcode,nfun_sc)
+c$$$
+c$$$      mask_r=.false.
+c$$$
+c$$$      return
+c$$$      end
+c$$$
+c$$$c-------------------------------------------------------------
+c$$$
+c$$$      subroutine minimize_sc(etot_sc,iretcode,nfun)
+c$$$c     Minimize side-chains only, starting from geom but without modifying
+c$$$c     bond lengths.
+c$$$c     If mask_r is already set, only the selected side-chains are minimized,
+c$$$c     otherwise all side-chains are minimized keeping the backbone frozen.
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.GEO'
+c$$$      include 'COMMON.MINIM'
+c$$$      integer icall
+c$$$      common /srutu/ icall
+c$$$
+c$$$c     Output arguments
+c$$$      double precision etot_sc
+c$$$      integer iretcode,nfun
+c$$$
+c$$$c     External functions/subroutines
+c$$$      external func_sc,grad_sc,fdum
+c$$$
+c$$$c     Local variables
+c$$$      integer liv,lv
+c$$$      parameter (liv=60,lv=(77+maxvar*(maxvar+17)/2)) 
+c$$$      integer iv(liv)
+c$$$      double precision rdum(1)
+c$$$      double precision d(maxvar),v(1:lv),x(maxvar),xx(maxvar)
+c$$$      integer idum(1)
+c$$$      integer i,nvar_restr
+c$$$
+c$$$
+c$$$cmc      start_minim=.true.
+c$$$      call deflt(2,iv,liv,lv,v)                                         
+c$$$* 12 means fresh start, dont call deflt                                 
+c$$$      iv(1)=12                                                          
+c$$$* max num of fun calls                                                  
+c$$$      if (maxfun.eq.0) maxfun=500
+c$$$      iv(17)=maxfun
+c$$$* max num of iterations                                                 
+c$$$      if (maxmin.eq.0) maxmin=1000
+c$$$      iv(18)=maxmin
+c$$$* controls output                                                       
+c$$$      iv(19)=1
+c$$$* selects output unit                                                   
+c$$$      iv(21)=0
+c$$$c      iv(21)=iout               ! DEBUG
+c$$$c      iv(21)=8                  ! DEBUG
+c$$$* 1 means to print out result                                           
+c$$$      iv(22)=0
+c$$$c      iv(22)=1                  ! DEBUG
+c$$$* 1 means to print out summary stats                                    
+c$$$      iv(23)=0                                                          
+c$$$c      iv(23)=1                  ! DEBUG
+c$$$* 1 means to print initial x and d                                      
+c$$$      iv(24)=0                                                          
+c$$$c      iv(24)=1                  ! DEBUG
+c$$$* min val for v(radfac) default is 0.1                                  
+c$$$      v(24)=0.1D0                                                       
+c$$$* max val for v(radfac) default is 4.0                                  
+c$$$      v(25)=2.0D0                                                       
+c$$$c     v(25)=4.0D0                                                       
+c$$$* check false conv if (act fnctn decrease) .lt. v(26)*(exp decrease)    
+c$$$* the sumsl default is 0.1                                              
+c$$$      v(26)=0.1D0
+c$$$* false conv if (act fnctn decrease) .lt. v(34)                         
+c$$$* the sumsl default is 100*machep                                       
+c$$$      v(34)=v(34)/100.0D0                                               
+c$$$* absolute convergence                                                  
+c$$$      if (tolf.eq.0.0D0) tolf=1.0D-4
+c$$$      v(31)=tolf
+c$$$* relative convergence                                                  
+c$$$      if (rtolf.eq.0.0D0) rtolf=1.0D-1
+c$$$      v(32)=rtolf
+c$$$* controls initial step size                                            
+c$$$       v(35)=1.0D-1                                                    
+c$$$* large vals of d correspond to small components of step                
+c$$$      do i=1,nphi
+c$$$        d(i)=1.0D-1
+c$$$      enddo
+c$$$      do i=nphi+1,nvar
+c$$$        d(i)=1.0D-1
+c$$$      enddo
+c$$$
+c$$$      call geom_to_var(nvar,x)
+c$$$      IF (mask_r) THEN
+c$$$        do i=1,nres             ! Just in case...
+c$$$          mask_phi(i)=0
+c$$$          mask_theta(i)=0
+c$$$        enddo
+c$$$        call x2xx(x,xx,nvar_restr)
+c$$$        call sumsl(nvar_restr,d,xx,func_sc,grad_sc,
+c$$$     &       iv,liv,lv,v,idum,rdum,fdum)      
+c$$$        call xx2x(x,xx)
+c$$$      ELSE
+c$$$c     When minimizing ALL side-chains, etotal_sc is a little
+c$$$c     faster if we don't set mask_r
+c$$$        do i=1,nres
+c$$$          mask_phi(i)=0
+c$$$          mask_theta(i)=0
+c$$$          mask_side(i)=1
+c$$$        enddo
+c$$$        call x2xx(x,xx,nvar_restr)
+c$$$        call sumsl(nvar_restr,d,xx,func_sc,grad_sc,
+c$$$     &       iv,liv,lv,v,idum,rdum,fdum)      
+c$$$        call xx2x(x,xx)
+c$$$      ENDIF
+c$$$      call var_to_geom(nvar,x)
+c$$$      call chainbuild_sc
+c$$$      etot_sc=v(10)                                                      
+c$$$      iretcode=iv(1)
+c$$$      nfun=iv(6)
+c$$$      return  
+c$$$      end  
+c$$$
+c$$$C--------------------------------------------------------------------------
+c$$$
+c$$$      subroutine chainbuild_sc
+c$$$      implicit none
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.INTERACT'
+c$$$
+c$$$c     Local variables
+c$$$      integer i
+c$$$
+c$$$
+c$$$      do i=nnt,nct
+c$$$        if (.not.mask_r .or. mask_side(i).eq.1) then
+c$$$          call locate_side_chain(i)
+c$$$        endif
+c$$$      enddo
+c$$$
+c$$$      return
+c$$$      end
+c$$$
+c$$$C--------------------------------------------------------------------------
+c$$$
+c$$$      subroutine func_sc(n,x,nf,f,uiparm,urparm,ufparm)  
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.MINIM'
+c$$$      include 'COMMON.IOUNITS'
+c$$$
+c$$$c     Input arguments
+c$$$      integer n
+c$$$      double precision x(maxvar)
+c$$$      double precision ufparm
+c$$$      external ufparm
+c$$$
+c$$$c     Input/Output arguments
+c$$$      integer nf
+c$$$      integer uiparm(1)
+c$$$      double precision urparm(1)
+c$$$
+c$$$c     Output arguments
+c$$$      double precision f
+c$$$
+c$$$c     Local variables
+c$$$      double precision energia(0:n_ene)
+c$$$#ifdef OSF
+c$$$c     Variables used to intercept NaNs
+c$$$      double precision x_sum
+c$$$      integer i_NAN
+c$$$#endif
+c$$$
+c$$$
+c$$$      nfl=nf
+c$$$      icg=mod(nf,2)+1
+c$$$
+c$$$#ifdef OSF
+c$$$c     Intercept NaNs in the coordinates, before calling etotal_sc
+c$$$      x_sum=0.D0
+c$$$      do i_NAN=1,n
+c$$$        x_sum=x_sum+x(i_NAN)
+c$$$      enddo
+c$$$c     Calculate the energy only if the coordinates are ok
+c$$$      if ((.not.(x_sum.lt.0.D0)) .and. (.not.(x_sum.ge.0.D0))) then
+c$$$        write(iout,*)"   *** func_restr_sc : Found NaN in coordinates"
+c$$$        f=1.0D+77
+c$$$        nf=0
+c$$$      else
+c$$$#endif
+c$$$
+c$$$      call var_to_geom_restr(n,x)
+c$$$      call zerograd
+c$$$      call chainbuild_sc
+c$$$      call etotal_sc(energia(0))
+c$$$      f=energia(0)
+c$$$      if (energia(1).eq.1.0D20 .or. energia(0).eq.1.0D99) nf=0
+c$$$
+c$$$#ifdef OSF
+c$$$      endif
+c$$$#endif
+c$$$
+c$$$      return                                                            
+c$$$      end                                                               
+c$$$
+c$$$c-------------------------------------------------------
+c$$$
+c$$$      subroutine grad_sc(n,x,nf,g,uiparm,urparm,ufparm)
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.INTERACT'
+c$$$      include 'COMMON.MINIM'
+c$$$
+c$$$c     Input arguments
+c$$$      integer n
+c$$$      double precision x(maxvar)
+c$$$      double precision ufparm
+c$$$      external ufparm
+c$$$
+c$$$c     Input/Output arguments
+c$$$      integer nf
+c$$$      integer uiparm(1)
+c$$$      double precision urparm(1)
+c$$$
+c$$$c     Output arguments
+c$$$      double precision g(maxvar)
+c$$$
+c$$$c     Local variables
+c$$$      double precision f,gphii,gthetai,galphai,gomegai
+c$$$      integer ig,ind,i,j,k,igall,ij
+c$$$
+c$$$
+c$$$      icg=mod(nf,2)+1
+c$$$      if (nf-nfl+1) 20,30,40
+c$$$   20 call func_sc(n,x,nf,f,uiparm,urparm,ufparm)
+c$$$c     write (iout,*) 'grad 20'
+c$$$      if (nf.eq.0) return
+c$$$      goto 40
+c$$$   30 call var_to_geom_restr(n,x)
+c$$$      call chainbuild_sc
+c$$$C
+c$$$C Evaluate the derivatives of virtual bond lengths and SC vectors in variables.
+c$$$C
+c$$$   40 call cartder
+c$$$C
+c$$$C Convert the Cartesian gradient into internal-coordinate gradient.
+c$$$C
+c$$$
+c$$$      ig=0
+c$$$      ind=nres-2
+c$$$      do i=2,nres-2
+c$$$       IF (mask_phi(i+2).eq.1) THEN
+c$$$        gphii=0.0D0
+c$$$        do j=i+1,nres-1
+c$$$          ind=ind+1
+c$$$          do k=1,3
+c$$$            gphii=gphii+dcdv(k+3,ind)*gradc(k,j,icg)
+c$$$            gphii=gphii+dxdv(k+3,ind)*gradx(k,j,icg)
+c$$$          enddo
+c$$$        enddo
+c$$$        ig=ig+1
+c$$$        g(ig)=gphii
+c$$$       ELSE
+c$$$        ind=ind+nres-1-i
+c$$$       ENDIF
+c$$$      enddo                                        
+c$$$
+c$$$
+c$$$      ind=0
+c$$$      do i=1,nres-2
+c$$$       IF (mask_theta(i+2).eq.1) THEN
+c$$$        ig=ig+1
+c$$$   gthetai=0.0D0
+c$$$   do j=i+1,nres-1
+c$$$          ind=ind+1
+c$$$     do k=1,3
+c$$$            gthetai=gthetai+dcdv(k,ind)*gradc(k,j,icg)
+c$$$            gthetai=gthetai+dxdv(k,ind)*gradx(k,j,icg)
+c$$$          enddo
+c$$$        enddo
+c$$$        g(ig)=gthetai
+c$$$       ELSE
+c$$$        ind=ind+nres-1-i
+c$$$       ENDIF
+c$$$      enddo
+c$$$
+c$$$      do i=2,nres-1
+c$$$   if (itype(i).ne.10) then
+c$$$         IF (mask_side(i).eq.1) THEN
+c$$$          ig=ig+1
+c$$$          galphai=0.0D0
+c$$$     do k=1,3
+c$$$       galphai=galphai+dxds(k,i)*gradx(k,i,icg)
+c$$$          enddo
+c$$$          g(ig)=galphai
+c$$$         ENDIF
+c$$$        endif
+c$$$      enddo
+c$$$
+c$$$      
+c$$$      do i=2,nres-1
+c$$$        if (itype(i).ne.10) then
+c$$$         IF (mask_side(i).eq.1) THEN
+c$$$          ig=ig+1
+c$$$     gomegai=0.0D0
+c$$$     do k=1,3
+c$$$       gomegai=gomegai+dxds(k+3,i)*gradx(k,i,icg)
+c$$$          enddo
+c$$$     g(ig)=gomegai
+c$$$         ENDIF
+c$$$        endif
+c$$$      enddo
+c$$$
+c$$$C
+c$$$C Add the components corresponding to local energy terms.
+c$$$C
+c$$$
+c$$$      ig=0
+c$$$      igall=0
+c$$$      do i=4,nres
+c$$$        igall=igall+1
+c$$$        if (mask_phi(i).eq.1) then
+c$$$          ig=ig+1
+c$$$          g(ig)=g(ig)+gloc(igall,icg)
+c$$$        endif
+c$$$      enddo
+c$$$
+c$$$      do i=3,nres
+c$$$        igall=igall+1
+c$$$        if (mask_theta(i).eq.1) then
+c$$$          ig=ig+1
+c$$$          g(ig)=g(ig)+gloc(igall,icg)
+c$$$        endif
+c$$$      enddo
+c$$$     
+c$$$      do ij=1,2
+c$$$      do i=2,nres-1
+c$$$        if (itype(i).ne.10) then
+c$$$          igall=igall+1
+c$$$          if (mask_side(i).eq.1) then
+c$$$            ig=ig+1
+c$$$            g(ig)=g(ig)+gloc(igall,icg)
+c$$$          endif
+c$$$        endif
+c$$$      enddo
+c$$$      enddo
+c$$$
+c$$$cd      do i=1,ig
+c$$$cd        write (iout,'(a2,i5,a3,f25.8)') 'i=',i,' g=',g(i)
+c$$$cd      enddo
+c$$$
+c$$$      return
+c$$$      end
+c$$$
+c$$$C-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine etotal_sc(energy_sc)
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.INTERACT'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.FFIELD'
+c$$$
+c$$$c     Output arguments
+c$$$      double precision energy_sc(0:n_ene)
+c$$$
+c$$$c     Local variables
+c$$$      double precision evdw,escloc
+c$$$      integer i,j
+c$$$
+c$$$
+c$$$      do i=1,n_ene
+c$$$        energy_sc(i)=0.0D0
+c$$$      enddo
+c$$$
+c$$$      if (mask_r) then
+c$$$        call egb_sc(evdw)
+c$$$        call esc_sc(escloc)
+c$$$      else
+c$$$        call egb(evdw)
+c$$$        call esc(escloc)
+c$$$      endif
+c$$$
+c$$$      if (evdw.eq.1.0D20) then
+c$$$        energy_sc(0)=evdw
+c$$$      else
+c$$$        energy_sc(0)=wsc*evdw+wscloc*escloc
+c$$$      endif
+c$$$      energy_sc(1)=evdw
+c$$$      energy_sc(12)=escloc
+c$$$
+c$$$C
+c$$$C Sum up the components of the Cartesian gradient.
+c$$$C
+c$$$      do i=1,nct
+c$$$        do j=1,3
+c$$$          gradx(j,i,icg)=wsc*gvdwx(j,i)
+c$$$        enddo
+c$$$      enddo
+c$$$
+c$$$      return
+c$$$      end
+c$$$
+c$$$C-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine egb_sc(evdw)
+c$$$C
+c$$$C This subroutine calculates the interaction energy of nonbonded side chains
+c$$$C assuming the Gay-Berne potential of interaction.
+c$$$C
+c$$$      implicit real*8 (a-h,o-z)
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.GEO'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.LOCAL'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.NAMES'
+c$$$      include 'COMMON.INTERACT'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.CALC'
+c$$$      include 'COMMON.CONTROL'
+c$$$      logical lprn
+c$$$      evdw=0.0D0
+c$$$      energy_dec=.false.
+c$$$c     print *,'Entering EGB nnt=',nnt,' nct=',nct,' expon=',expon
+c$$$      evdw=0.0D0
+c$$$      lprn=.false.
+c$$$c     if (icall.eq.0) lprn=.false.
+c$$$      ind=0
+c$$$      do i=iatsc_s,iatsc_e
+c$$$        itypi=itype(i)
+c$$$        itypi1=itype(i+1)
+c$$$        xi=c(1,nres+i)
+c$$$        yi=c(2,nres+i)
+c$$$        zi=c(3,nres+i)
+c$$$        dxi=dc_norm(1,nres+i)
+c$$$        dyi=dc_norm(2,nres+i)
+c$$$        dzi=dc_norm(3,nres+i)
+c$$$c        dsci_inv=dsc_inv(itypi)
+c$$$        dsci_inv=vbld_inv(i+nres)
+c$$$c        write (iout,*) "i",i,dsc_inv(itypi),dsci_inv,1.0d0/vbld(i+nres)
+c$$$c        write (iout,*) "dcnori",dxi*dxi+dyi*dyi+dzi*dzi
+c$$$C
+c$$$C Calculate SC interaction energy.
+c$$$C
+c$$$        do iint=1,nint_gr(i)
+c$$$          do j=istart(i,iint),iend(i,iint)
+c$$$          IF (mask_side(j).eq.1.or.mask_side(i).eq.1) THEN
+c$$$            ind=ind+1
+c$$$            itypj=itype(j)
+c$$$c            dscj_inv=dsc_inv(itypj)
+c$$$            dscj_inv=vbld_inv(j+nres)
+c$$$c            write (iout,*) "j",j,dsc_inv(itypj),dscj_inv,
+c$$$c     &       1.0d0/vbld(j+nres)
+c$$$c            write (iout,*) "i",i," j", j," itype",itype(i),itype(j)
+c$$$            sig0ij=sigma(itypi,itypj)
+c$$$            chi1=chi(itypi,itypj)
+c$$$            chi2=chi(itypj,itypi)
+c$$$            chi12=chi1*chi2
+c$$$            chip1=chip(itypi)
+c$$$            chip2=chip(itypj)
+c$$$            chip12=chip1*chip2
+c$$$            alf1=alp(itypi)
+c$$$            alf2=alp(itypj)
+c$$$            alf12=0.5D0*(alf1+alf2)
+c$$$C For diagnostics only!!!
+c$$$c           chi1=0.0D0
+c$$$c           chi2=0.0D0
+c$$$c           chi12=0.0D0
+c$$$c           chip1=0.0D0
+c$$$c           chip2=0.0D0
+c$$$c           chip12=0.0D0
+c$$$c           alf1=0.0D0
+c$$$c           alf2=0.0D0
+c$$$c           alf12=0.0D0
+c$$$            xj=c(1,nres+j)-xi
+c$$$            yj=c(2,nres+j)-yi
+c$$$            zj=c(3,nres+j)-zi
+c$$$            dxj=dc_norm(1,nres+j)
+c$$$            dyj=dc_norm(2,nres+j)
+c$$$            dzj=dc_norm(3,nres+j)
+c$$$c            write (iout,*) "dcnorj",dxi*dxi+dyi*dyi+dzi*dzi
+c$$$c            write (iout,*) "j",j," dc_norm",
+c$$$c     &       dc_norm(1,nres+j),dc_norm(2,nres+j),dc_norm(3,nres+j)
+c$$$            rrij=1.0D0/(xj*xj+yj*yj+zj*zj)
+c$$$            rij=dsqrt(rrij)
+c$$$C Calculate angle-dependent terms of energy and contributions to their
+c$$$C derivatives.
+c$$$            call sc_angular
+c$$$            sigsq=1.0D0/sigsq
+c$$$            sig=sig0ij*dsqrt(sigsq)
+c$$$            rij_shift=1.0D0/rij-sig+sig0ij
+c$$$c for diagnostics; uncomment
+c$$$c            rij_shift=1.2*sig0ij
+c$$$C I hate to put IF's in the loops, but here don't have another choice!!!!
+c$$$            if (rij_shift.le.0.0D0) then
+c$$$              evdw=1.0D20
+c$$$cd              write (iout,'(2(a3,i3,2x),17(0pf7.3))')
+c$$$cd     &        restyp(itypi),i,restyp(itypj),j,
+c$$$cd     &        rij_shift,1.0D0/rij,sig,sig0ij,sigsq,1-dsqrt(sigsq) 
+c$$$              return
+c$$$            endif
+c$$$            sigder=-sig*sigsq
+c$$$c---------------------------------------------------------------
+c$$$            rij_shift=1.0D0/rij_shift 
+c$$$            fac=rij_shift**expon
+c$$$            e1=fac*fac*aa(itypi,itypj)
+c$$$            e2=fac*bb(itypi,itypj)
+c$$$            evdwij=eps1*eps2rt*eps3rt*(e1+e2)
+c$$$            eps2der=evdwij*eps3rt
+c$$$            eps3der=evdwij*eps2rt
+c$$$c            write (iout,*) "sigsq",sigsq," sig",sig," eps2rt",eps2rt,
+c$$$c     &        " eps3rt",eps3rt," eps1",eps1," e1",e1," e2",e2
+c$$$            evdwij=evdwij*eps2rt*eps3rt
+c$$$            evdw=evdw+evdwij
+c$$$            if (lprn) then
+c$$$            sigm=dabs(aa(itypi,itypj)/bb(itypi,itypj))**(1.0D0/6.0D0)
+c$$$            epsi=bb(itypi,itypj)**2/aa(itypi,itypj)
+c$$$            write (iout,'(2(a3,i3,2x),17(0pf7.3))')
+c$$$     &        restyp(itypi),i,restyp(itypj),j,
+c$$$     &        epsi,sigm,chi1,chi2,chip1,chip2,
+c$$$     &        eps1,eps2rt**2,eps3rt**2,sig,sig0ij,
+c$$$     &        om1,om2,om12,1.0D0/rij,1.0D0/rij_shift,
+c$$$     &        evdwij
+c$$$            endif
+c$$$
+c$$$            if (energy_dec) write (iout,'(a6,2i,0pf7.3)') 
+c$$$     &                        'evdw',i,j,evdwij
+c$$$
+c$$$C Calculate gradient components.
+c$$$            e1=e1*eps1*eps2rt**2*eps3rt**2
+c$$$            fac=-expon*(e1+evdwij)*rij_shift
+c$$$            sigder=fac*sigder
+c$$$            fac=rij*fac
+c$$$c            fac=0.0d0
+c$$$C Calculate the radial part of the gradient
+c$$$            gg(1)=xj*fac
+c$$$            gg(2)=yj*fac
+c$$$            gg(3)=zj*fac
+c$$$C Calculate angular part of the gradient.
+c$$$            call sc_grad
+c$$$          ENDIF
+c$$$          enddo      ! j
+c$$$        enddo        ! iint
+c$$$      enddo          ! i
+c$$$      energy_dec=.false.
+c$$$      return
+c$$$      end
+c$$$
+c$$$c-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine esc_sc(escloc)
+c$$$C Calculate the local energy of a side chain and its derivatives in the
+c$$$C corresponding virtual-bond valence angles THETA and the spherical angles 
+c$$$C ALPHA and OMEGA.
+c$$$      implicit real*8 (a-h,o-z)
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.GEO'
+c$$$      include 'COMMON.LOCAL'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.INTERACT'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.NAMES'
+c$$$      include 'COMMON.FFIELD'
+c$$$      include 'COMMON.CONTROL'
+c$$$      double precision x(3),dersc(3),xemp(3),dersc0(3),dersc1(3),
+c$$$     &     ddersc0(3),ddummy(3),xtemp(3),temp(3)
+c$$$      common /sccalc/ time11,time12,time112,theti,it,nlobit
+c$$$      delta=0.02d0*pi
+c$$$      escloc=0.0D0
+c$$$c     write (iout,'(a)') 'ESC'
+c$$$      do i=loc_start,loc_end
+c$$$      IF (mask_side(i).eq.1) THEN
+c$$$        it=itype(i)
+c$$$        if (it.eq.10) goto 1
+c$$$        nlobit=nlob(it)
+c$$$c       print *,'i=',i,' it=',it,' nlobit=',nlobit
+c$$$c       write (iout,*) 'i=',i,' ssa=',ssa,' ssad=',ssad
+c$$$        theti=theta(i+1)-pipol
+c$$$        x(1)=dtan(theti)
+c$$$        x(2)=alph(i)
+c$$$        x(3)=omeg(i)
+c$$$
+c$$$        if (x(2).gt.pi-delta) then
+c$$$          xtemp(1)=x(1)
+c$$$          xtemp(2)=pi-delta
+c$$$          xtemp(3)=x(3)
+c$$$          call enesc(xtemp,escloci0,dersc0,ddersc0,.true.)
+c$$$          xtemp(2)=pi
+c$$$          call enesc(xtemp,escloci1,dersc1,ddummy,.false.)
+c$$$          call spline1(x(2),pi-delta,delta,escloci0,escloci1,dersc0(2),
+c$$$     &        escloci,dersc(2))
+c$$$          call spline2(x(2),pi-delta,delta,dersc0(1),dersc1(1),
+c$$$     &        ddersc0(1),dersc(1))
+c$$$          call spline2(x(2),pi-delta,delta,dersc0(3),dersc1(3),
+c$$$     &        ddersc0(3),dersc(3))
+c$$$          xtemp(2)=pi-delta
+c$$$          call enesc_bound(xtemp,esclocbi0,dersc0,dersc12,.true.)
+c$$$          xtemp(2)=pi
+c$$$          call enesc_bound(xtemp,esclocbi1,dersc1,chuju,.false.)
+c$$$          call spline1(x(2),pi-delta,delta,esclocbi0,esclocbi1,
+c$$$     &            dersc0(2),esclocbi,dersc02)
+c$$$          call spline2(x(2),pi-delta,delta,dersc0(1),dersc1(1),
+c$$$     &            dersc12,dersc01)
+c$$$          call splinthet(x(2),0.5d0*delta,ss,ssd)
+c$$$          dersc0(1)=dersc01
+c$$$          dersc0(2)=dersc02
+c$$$          dersc0(3)=0.0d0
+c$$$          do k=1,3
+c$$$            dersc(k)=ss*dersc(k)+(1.0d0-ss)*dersc0(k)
+c$$$          enddo
+c$$$          dersc(2)=dersc(2)+ssd*(escloci-esclocbi)
+c$$$c         write (iout,*) 'i=',i,x(2)*rad2deg,escloci0,escloci,
+c$$$c    &             esclocbi,ss,ssd
+c$$$          escloci=ss*escloci+(1.0d0-ss)*esclocbi
+c$$$c         escloci=esclocbi
+c$$$c         write (iout,*) escloci
+c$$$        else if (x(2).lt.delta) then
+c$$$          xtemp(1)=x(1)
+c$$$          xtemp(2)=delta
+c$$$          xtemp(3)=x(3)
+c$$$          call enesc(xtemp,escloci0,dersc0,ddersc0,.true.)
+c$$$          xtemp(2)=0.0d0
+c$$$          call enesc(xtemp,escloci1,dersc1,ddummy,.false.)
+c$$$          call spline1(x(2),delta,-delta,escloci0,escloci1,dersc0(2),
+c$$$     &        escloci,dersc(2))
+c$$$          call spline2(x(2),delta,-delta,dersc0(1),dersc1(1),
+c$$$     &        ddersc0(1),dersc(1))
+c$$$          call spline2(x(2),delta,-delta,dersc0(3),dersc1(3),
+c$$$     &        ddersc0(3),dersc(3))
+c$$$          xtemp(2)=delta
+c$$$          call enesc_bound(xtemp,esclocbi0,dersc0,dersc12,.true.)
+c$$$          xtemp(2)=0.0d0
+c$$$          call enesc_bound(xtemp,esclocbi1,dersc1,chuju,.false.)
+c$$$          call spline1(x(2),delta,-delta,esclocbi0,esclocbi1,
+c$$$     &            dersc0(2),esclocbi,dersc02)
+c$$$          call spline2(x(2),delta,-delta,dersc0(1),dersc1(1),
+c$$$     &            dersc12,dersc01)
+c$$$          dersc0(1)=dersc01
+c$$$          dersc0(2)=dersc02
+c$$$          dersc0(3)=0.0d0
+c$$$          call splinthet(x(2),0.5d0*delta,ss,ssd)
+c$$$          do k=1,3
+c$$$            dersc(k)=ss*dersc(k)+(1.0d0-ss)*dersc0(k)
+c$$$          enddo
+c$$$          dersc(2)=dersc(2)+ssd*(escloci-esclocbi)
+c$$$c         write (iout,*) 'i=',i,x(2)*rad2deg,escloci0,escloci,
+c$$$c    &             esclocbi,ss,ssd
+c$$$          escloci=ss*escloci+(1.0d0-ss)*esclocbi
+c$$$c         write (iout,*) escloci
+c$$$        else
+c$$$          call enesc(x,escloci,dersc,ddummy,.false.)
+c$$$        endif
+c$$$
+c$$$        escloc=escloc+escloci
+c$$$        if (energy_dec) write (iout,'(a6,i,0pf7.3)')
+c$$$     &     'escloc',i,escloci
+c$$$c       write (iout,*) 'i=',i,' escloci=',escloci,' dersc=',dersc
+c$$$
+c$$$        gloc(nphi+i-1,icg)=gloc(nphi+i-1,icg)+
+c$$$     &   wscloc*dersc(1)
+c$$$        gloc(ialph(i,1),icg)=wscloc*dersc(2)
+c$$$        gloc(ialph(i,1)+nside,icg)=wscloc*dersc(3)
+c$$$    1   continue
+c$$$      ENDIF
+c$$$      enddo
+c$$$      return
+c$$$      end
+c$$$
+c$$$C-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine egb_ij(i_sc,j_sc,evdw)
+c$$$C
+c$$$C This subroutine calculates the interaction energy of nonbonded side chains
+c$$$C assuming the Gay-Berne potential of interaction.
+c$$$C
+c$$$      implicit real*8 (a-h,o-z)
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.GEO'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.LOCAL'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.NAMES'
+c$$$      include 'COMMON.INTERACT'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.CALC'
+c$$$      include 'COMMON.CONTROL'
+c$$$      logical lprn
+c$$$      evdw=0.0D0
+c$$$      energy_dec=.false.
+c$$$c     print *,'Entering EGB nnt=',nnt,' nct=',nct,' expon=',expon
+c$$$      evdw=0.0D0
+c$$$      lprn=.false.
+c$$$      ind=0
+c$$$c$$$      do i=iatsc_s,iatsc_e
+c$$$      i=i_sc
+c$$$        itypi=itype(i)
+c$$$        itypi1=itype(i+1)
+c$$$        xi=c(1,nres+i)
+c$$$        yi=c(2,nres+i)
+c$$$        zi=c(3,nres+i)
+c$$$        dxi=dc_norm(1,nres+i)
+c$$$        dyi=dc_norm(2,nres+i)
+c$$$        dzi=dc_norm(3,nres+i)
+c$$$c        dsci_inv=dsc_inv(itypi)
+c$$$        dsci_inv=vbld_inv(i+nres)
+c$$$c        write (iout,*) "i",i,dsc_inv(itypi),dsci_inv,1.0d0/vbld(i+nres)
+c$$$c        write (iout,*) "dcnori",dxi*dxi+dyi*dyi+dzi*dzi
+c$$$C
+c$$$C Calculate SC interaction energy.
+c$$$C
+c$$$c$$$        do iint=1,nint_gr(i)
+c$$$c$$$          do j=istart(i,iint),iend(i,iint)
+c$$$        j=j_sc
+c$$$            ind=ind+1
+c$$$            itypj=itype(j)
+c$$$c            dscj_inv=dsc_inv(itypj)
+c$$$            dscj_inv=vbld_inv(j+nres)
+c$$$c            write (iout,*) "j",j,dsc_inv(itypj),dscj_inv,
+c$$$c     &       1.0d0/vbld(j+nres)
+c$$$c            write (iout,*) "i",i," j", j," itype",itype(i),itype(j)
+c$$$            sig0ij=sigma(itypi,itypj)
+c$$$            chi1=chi(itypi,itypj)
+c$$$            chi2=chi(itypj,itypi)
+c$$$            chi12=chi1*chi2
+c$$$            chip1=chip(itypi)
+c$$$            chip2=chip(itypj)
+c$$$            chip12=chip1*chip2
+c$$$            alf1=alp(itypi)
+c$$$            alf2=alp(itypj)
+c$$$            alf12=0.5D0*(alf1+alf2)
+c$$$C For diagnostics only!!!
+c$$$c           chi1=0.0D0
+c$$$c           chi2=0.0D0
+c$$$c           chi12=0.0D0
+c$$$c           chip1=0.0D0
+c$$$c           chip2=0.0D0
+c$$$c           chip12=0.0D0
+c$$$c           alf1=0.0D0
+c$$$c           alf2=0.0D0
+c$$$c           alf12=0.0D0
+c$$$            xj=c(1,nres+j)-xi
+c$$$            yj=c(2,nres+j)-yi
+c$$$            zj=c(3,nres+j)-zi
+c$$$            dxj=dc_norm(1,nres+j)
+c$$$            dyj=dc_norm(2,nres+j)
+c$$$            dzj=dc_norm(3,nres+j)
+c$$$c            write (iout,*) "dcnorj",dxi*dxi+dyi*dyi+dzi*dzi
+c$$$c            write (iout,*) "j",j," dc_norm",
+c$$$c     &       dc_norm(1,nres+j),dc_norm(2,nres+j),dc_norm(3,nres+j)
+c$$$            rrij=1.0D0/(xj*xj+yj*yj+zj*zj)
+c$$$            rij=dsqrt(rrij)
+c$$$C Calculate angle-dependent terms of energy and contributions to their
+c$$$C derivatives.
+c$$$            call sc_angular
+c$$$            sigsq=1.0D0/sigsq
+c$$$            sig=sig0ij*dsqrt(sigsq)
+c$$$            rij_shift=1.0D0/rij-sig+sig0ij
+c$$$c for diagnostics; uncomment
+c$$$c            rij_shift=1.2*sig0ij
+c$$$C I hate to put IF's in the loops, but here don't have another choice!!!!
+c$$$            if (rij_shift.le.0.0D0) then
+c$$$              evdw=1.0D20
+c$$$cd              write (iout,'(2(a3,i3,2x),17(0pf7.3))')
+c$$$cd     &        restyp(itypi),i,restyp(itypj),j,
+c$$$cd     &        rij_shift,1.0D0/rij,sig,sig0ij,sigsq,1-dsqrt(sigsq) 
+c$$$              return
+c$$$            endif
+c$$$            sigder=-sig*sigsq
+c$$$c---------------------------------------------------------------
+c$$$            rij_shift=1.0D0/rij_shift 
+c$$$            fac=rij_shift**expon
+c$$$            e1=fac*fac*aa(itypi,itypj)
+c$$$            e2=fac*bb(itypi,itypj)
+c$$$            evdwij=eps1*eps2rt*eps3rt*(e1+e2)
+c$$$            eps2der=evdwij*eps3rt
+c$$$            eps3der=evdwij*eps2rt
+c$$$c            write (iout,*) "sigsq",sigsq," sig",sig," eps2rt",eps2rt,
+c$$$c     &        " eps3rt",eps3rt," eps1",eps1," e1",e1," e2",e2
+c$$$            evdwij=evdwij*eps2rt*eps3rt
+c$$$            evdw=evdw+evdwij
+c$$$            if (lprn) then
+c$$$            sigm=dabs(aa(itypi,itypj)/bb(itypi,itypj))**(1.0D0/6.0D0)
+c$$$            epsi=bb(itypi,itypj)**2/aa(itypi,itypj)
+c$$$            write (iout,'(2(a3,i3,2x),17(0pf7.3))')
+c$$$     &        restyp(itypi),i,restyp(itypj),j,
+c$$$     &        epsi,sigm,chi1,chi2,chip1,chip2,
+c$$$     &        eps1,eps2rt**2,eps3rt**2,sig,sig0ij,
+c$$$     &        om1,om2,om12,1.0D0/rij,1.0D0/rij_shift,
+c$$$     &        evdwij
+c$$$            endif
+c$$$
+c$$$            if (energy_dec) write (iout,'(a6,2i,0pf7.3)') 
+c$$$     &                        'evdw',i,j,evdwij
+c$$$
+c$$$C Calculate gradient components.
+c$$$            e1=e1*eps1*eps2rt**2*eps3rt**2
+c$$$            fac=-expon*(e1+evdwij)*rij_shift
+c$$$            sigder=fac*sigder
+c$$$            fac=rij*fac
+c$$$c            fac=0.0d0
+c$$$C Calculate the radial part of the gradient
+c$$$            gg(1)=xj*fac
+c$$$            gg(2)=yj*fac
+c$$$            gg(3)=zj*fac
+c$$$C Calculate angular part of the gradient.
+c$$$            call sc_grad
+c$$$c$$$          enddo      ! j
+c$$$c$$$        enddo        ! iint
+c$$$c$$$      enddo          ! i
+c$$$      energy_dec=.false.
+c$$$      return
+c$$$      end
+c$$$
+c$$$C-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine perturb_side_chain(i,angle)
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.GEO'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.LOCAL'
+c$$$      include 'COMMON.IOUNITS'
+c$$$
+c$$$c     External functions
+c$$$      external ran_number
+c$$$      double precision ran_number
+c$$$
+c$$$c     Input arguments
+c$$$      integer i
+c$$$      double precision angle    ! In degrees
+c$$$
+c$$$c     Local variables
+c$$$      integer i_sc
+c$$$      double precision rad_ang,rand_v(3),length,cost,sint
+c$$$
+c$$$
+c$$$      i_sc=i+nres
+c$$$      rad_ang=angle*deg2rad
+c$$$
+c$$$      length=0.0
+c$$$      do while (length.lt.0.01)
+c$$$        rand_v(1)=ran_number(0.01D0,1.0D0)
+c$$$        rand_v(2)=ran_number(0.01D0,1.0D0)
+c$$$        rand_v(3)=ran_number(0.01D0,1.0D0)
+c$$$        length=rand_v(1)*rand_v(1)+rand_v(2)*rand_v(2)+
+c$$$     +       rand_v(3)*rand_v(3)
+c$$$        length=sqrt(length)
+c$$$        rand_v(1)=rand_v(1)/length
+c$$$        rand_v(2)=rand_v(2)/length
+c$$$        rand_v(3)=rand_v(3)/length
+c$$$        cost=rand_v(1)*dc_norm(1,i_sc)+rand_v(2)*dc_norm(2,i_sc)+
+c$$$     +       rand_v(3)*dc_norm(3,i_sc)
+c$$$        length=1.0D0-cost*cost
+c$$$        if (length.lt.0.0D0) length=0.0D0
+c$$$        length=sqrt(length)
+c$$$        rand_v(1)=rand_v(1)-cost*dc_norm(1,i_sc)
+c$$$        rand_v(2)=rand_v(2)-cost*dc_norm(2,i_sc)
+c$$$        rand_v(3)=rand_v(3)-cost*dc_norm(3,i_sc)
+c$$$      enddo
+c$$$      rand_v(1)=rand_v(1)/length
+c$$$      rand_v(2)=rand_v(2)/length
+c$$$      rand_v(3)=rand_v(3)/length
+c$$$
+c$$$      cost=dcos(rad_ang)
+c$$$      sint=dsin(rad_ang)
+c$$$      dc(1,i_sc)=vbld(i_sc)*(dc_norm(1,i_sc)*cost+rand_v(1)*sint)
+c$$$      dc(2,i_sc)=vbld(i_sc)*(dc_norm(2,i_sc)*cost+rand_v(2)*sint)
+c$$$      dc(3,i_sc)=vbld(i_sc)*(dc_norm(3,i_sc)*cost+rand_v(3)*sint)
+c$$$      dc_norm(1,i_sc)=dc(1,i_sc)*vbld_inv(i_sc)
+c$$$      dc_norm(2,i_sc)=dc(2,i_sc)*vbld_inv(i_sc)
+c$$$      dc_norm(3,i_sc)=dc(3,i_sc)*vbld_inv(i_sc)
+c$$$      c(1,i_sc)=c(1,i)+dc(1,i_sc)
+c$$$      c(2,i_sc)=c(2,i)+dc(2,i_sc)
+c$$$      c(3,i_sc)=c(3,i)+dc(3,i_sc)
+c$$$
+c$$$      call chainbuild_cart
+c$$$
+c$$$      return
+c$$$      end
+c$$$
+c$$$c----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine ss_relax3(i_in,j_in)
+c$$$      implicit none
+c$$$
+c$$$c     Includes
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.INTERACT'
+c$$$
+c$$$c     External functions
+c$$$      external ran_number
+c$$$      double precision ran_number
+c$$$
+c$$$c     Input arguments
+c$$$      integer i_in,j_in
+c$$$
+c$$$c     Local variables
+c$$$      double precision energy_sc(0:n_ene),etot
+c$$$      double precision org_dc(3),org_dc_norm(3),org_c(3)
+c$$$      double precision ang_pert,rand_fact,exp_fact,beta
+c$$$      integer n,i_pert,i
+c$$$      logical notdone
+c$$$
+c$$$
+c$$$      beta=1.0D0
+c$$$
+c$$$      mask_r=.true.
+c$$$      do i=nnt,nct
+c$$$        mask_side(i)=0
+c$$$      enddo
+c$$$      mask_side(i_in)=1
+c$$$      mask_side(j_in)=1
+c$$$
+c$$$      call etotal_sc(energy_sc)
+c$$$      etot=energy_sc(0)
+c$$$c      write(iout,'(a,3d15.5)')"     SS_MC_START ",energy_sc(0),
+c$$$c     +     energy_sc(1),energy_sc(12)
+c$$$
+c$$$      notdone=.true.
+c$$$      n=0
+c$$$      do while (notdone)
+c$$$        if (mod(n,2).eq.0) then
+c$$$          i_pert=i_in
+c$$$        else
+c$$$          i_pert=j_in
+c$$$        endif
+c$$$        n=n+1
+c$$$
+c$$$        do i=1,3
+c$$$          org_dc(i)=dc(i,i_pert+nres)
+c$$$          org_dc_norm(i)=dc_norm(i,i_pert+nres)
+c$$$          org_c(i)=c(i,i_pert+nres)
+c$$$        enddo
+c$$$        ang_pert=ran_number(0.0D0,3.0D0)
+c$$$        call perturb_side_chain(i_pert,ang_pert)
+c$$$        call etotal_sc(energy_sc)
+c$$$        exp_fact=exp(beta*(etot-energy_sc(0)))
+c$$$        rand_fact=ran_number(0.0D0,1.0D0)
+c$$$        if (rand_fact.lt.exp_fact) then
+c$$$c          write(iout,'(a,3d15.5)')"     SS_MC_ACCEPT ",energy_sc(0),
+c$$$c     +     energy_sc(1),energy_sc(12)
+c$$$          etot=energy_sc(0)
+c$$$        else
+c$$$c          write(iout,'(a,3d15.5)')"     SS_MC_REJECT ",energy_sc(0),
+c$$$c     +     energy_sc(1),energy_sc(12)
+c$$$          do i=1,3
+c$$$            dc(i,i_pert+nres)=org_dc(i)
+c$$$            dc_norm(i,i_pert+nres)=org_dc_norm(i)
+c$$$            c(i,i_pert+nres)=org_c(i)
+c$$$          enddo
+c$$$        endif
+c$$$
+c$$$        if (n.eq.10000.or.etot.lt.30.0D0) notdone=.false.
+c$$$      enddo
+c$$$
+c$$$      mask_r=.false.
+c$$$
+c$$$      return
+c$$$      end
+c$$$
+c$$$c----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine ss_relax2(etot,iretcode,nfun,i_in,j_in)
+c$$$      implicit none
+c$$$      include 'DIMENSIONS'
+c$$$      integer liv,lv
+c$$$      parameter (liv=60,lv=(77+maxres6*(maxres6+17)/2)) 
+c$$$*********************************************************************
+c$$$* OPTIMIZE sets up SUMSL or DFP and provides a simple interface for *
+c$$$* the calling subprogram.                                           *     
+c$$$* when d(i)=1.0, then v(35) is the length of the initial step,      *     
+c$$$* calculated in the usual pythagorean way.                          *     
+c$$$* absolute convergence occurs when the function is within v(31) of  *     
+c$$$* zero. unless you know the minimum value in advance, abs convg     *     
+c$$$* is probably not useful.                                           *     
+c$$$* relative convergence is when the model predicts that the function *   
+c$$$* will decrease by less than v(32)*abs(fun).                        *   
+c$$$*********************************************************************
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.GEO'
+c$$$      include 'COMMON.MINIM'
+c$$$      include 'COMMON.CHAIN'
+c$$$
+c$$$      double precision orig_ss_dc,orig_ss_var,orig_ss_dist
+c$$$      common /orig_ss/ orig_ss_dc(3,0:maxres2),orig_ss_var(maxvar),
+c$$$     +     orig_ss_dist(maxres2,maxres2)
+c$$$
+c$$$      double precision etot
+c$$$      integer iretcode,nfun,i_in,j_in
+c$$$
+c$$$      external dist
+c$$$      double precision dist
+c$$$      external ss_func,fdum
+c$$$      double precision ss_func,fdum
+c$$$
+c$$$      integer iv(liv),uiparm(2)
+c$$$      double precision v(lv),x(maxres6),d(maxres6),rdum
+c$$$      integer i,j,k
+c$$$
+c$$$
+c$$$      call deflt(2,iv,liv,lv,v)                                         
+c$$$* 12 means fresh start, dont call deflt                                 
+c$$$      iv(1)=12                                                          
+c$$$* max num of fun calls                                                  
+c$$$      if (maxfun.eq.0) maxfun=500
+c$$$      iv(17)=maxfun
+c$$$* max num of iterations                                                 
+c$$$      if (maxmin.eq.0) maxmin=1000
+c$$$      iv(18)=maxmin
+c$$$* controls output                                                       
+c$$$      iv(19)=2                                                          
+c$$$* selects output unit                                                   
+c$$$c      iv(21)=iout                                                       
+c$$$      iv(21)=0
+c$$$* 1 means to print out result                                           
+c$$$      iv(22)=0                                                          
+c$$$* 1 means to print out summary stats                                    
+c$$$      iv(23)=0                                                          
+c$$$* 1 means to print initial x and d                                      
+c$$$      iv(24)=0                                                          
+c$$$* min val for v(radfac) default is 0.1                                  
+c$$$      v(24)=0.1D0                                                       
+c$$$* max val for v(radfac) default is 4.0                                  
+c$$$      v(25)=2.0D0                                                       
+c$$$c     v(25)=4.0D0                                                       
+c$$$* check false conv if (act fnctn decrease) .lt. v(26)*(exp decrease)    
+c$$$* the sumsl default is 0.1                                              
+c$$$      v(26)=0.1D0
+c$$$* false conv if (act fnctn decrease) .lt. v(34)                         
+c$$$* the sumsl default is 100*machep                                       
+c$$$      v(34)=v(34)/100.0D0                                               
+c$$$* absolute convergence                                                  
+c$$$      if (tolf.eq.0.0D0) tolf=1.0D-4
+c$$$      v(31)=tolf
+c$$$      v(31)=1.0D-1
+c$$$* relative convergence                                                  
+c$$$      if (rtolf.eq.0.0D0) rtolf=1.0D-4
+c$$$      v(32)=rtolf
+c$$$      v(32)=1.0D-1
+c$$$* controls initial step size                                            
+c$$$      v(35)=1.0D-1
+c$$$* large vals of d correspond to small components of step                
+c$$$      do i=1,6*nres
+c$$$        d(i)=1.0D0
+c$$$      enddo
+c$$$
+c$$$      do i=0,2*nres
+c$$$        do j=1,3
+c$$$          orig_ss_dc(j,i)=dc(j,i)
+c$$$        enddo
+c$$$      enddo
+c$$$      call geom_to_var(nvar,orig_ss_var)
+c$$$
+c$$$      do i=1,nres
+c$$$        do j=i,nres
+c$$$          orig_ss_dist(j,i)=dist(j,i)
+c$$$          orig_ss_dist(j+nres,i)=dist(j+nres,i)
+c$$$          orig_ss_dist(j,i+nres)=dist(j,i+nres)
+c$$$          orig_ss_dist(j+nres,i+nres)=dist(j+nres,i+nres)
+c$$$        enddo
+c$$$      enddo
+c$$$
+c$$$      k=0
+c$$$      do i=1,nres-1
+c$$$        do j=1,3
+c$$$          k=k+1
+c$$$          x(k)=dc(j,i)
+c$$$        enddo
+c$$$      enddo
+c$$$      do i=2,nres-1
+c$$$        if (ialph(i,1).gt.0) then
+c$$$        do j=1,3
+c$$$          k=k+1
+c$$$          x(k)=dc(j,i+nres)
+c$$$        enddo
+c$$$        endif
+c$$$      enddo
+c$$$
+c$$$      uiparm(1)=i_in
+c$$$      uiparm(2)=j_in
+c$$$      call smsno(k,d,x,ss_func,iv,liv,lv,v,uiparm,rdum,fdum)
+c$$$      etot=v(10)
+c$$$      iretcode=iv(1)
+c$$$      nfun=iv(6)+iv(30)
+c$$$
+c$$$      k=0
+c$$$      do i=1,nres-1
+c$$$        do j=1,3
+c$$$          k=k+1
+c$$$          dc(j,i)=x(k)
+c$$$        enddo
+c$$$      enddo
+c$$$      do i=2,nres-1
+c$$$        if (ialph(i,1).gt.0) then
+c$$$        do j=1,3
+c$$$          k=k+1
+c$$$          dc(j,i+nres)=x(k)
+c$$$        enddo
+c$$$        endif
+c$$$      enddo
+c$$$      call chainbuild_cart
+c$$$
+c$$$      return  
+c$$$      end  
+c$$$
+c$$$C-----------------------------------------------------------------------------
+c$$$
+c$$$      subroutine ss_func(n,x,nf,f,uiparm,urparm,ufparm)  
+c$$$      implicit none
+c$$$      include 'DIMENSIONS'
+c$$$      include 'COMMON.DERIV'
+c$$$      include 'COMMON.IOUNITS'
+c$$$      include 'COMMON.VAR'
+c$$$      include 'COMMON.CHAIN'
+c$$$      include 'COMMON.INTERACT'
+c$$$      include 'COMMON.SBRIDGE'
+c$$$
+c$$$      double precision orig_ss_dc,orig_ss_var,orig_ss_dist
+c$$$      common /orig_ss/ orig_ss_dc(3,0:maxres2),orig_ss_var(maxvar),
+c$$$     +     orig_ss_dist(maxres2,maxres2)
+c$$$
+c$$$      integer n
+c$$$      double precision x(maxres6)
+c$$$      integer nf
+c$$$      double precision f
+c$$$      integer uiparm(2)
+c$$$      real*8 urparm(1)
+c$$$      external ufparm
+c$$$      double precision ufparm
+c$$$
+c$$$      external dist
+c$$$      double precision dist
+c$$$
+c$$$      integer i,j,k,ss_i,ss_j
+c$$$      double precision tempf,var(maxvar)
+c$$$
+c$$$
+c$$$      ss_i=uiparm(1)
+c$$$      ss_j=uiparm(2)
+c$$$      f=0.0D0
+c$$$
+c$$$      k=0
+c$$$      do i=1,nres-1
+c$$$        do j=1,3
+c$$$          k=k+1
+c$$$          dc(j,i)=x(k)
+c$$$        enddo
+c$$$      enddo
+c$$$      do i=2,nres-1
+c$$$        if (ialph(i,1).gt.0) then
+c$$$        do j=1,3
+c$$$          k=k+1
+c$$$          dc(j,i+nres)=x(k)
+c$$$        enddo
+c$$$        endif
+c$$$      enddo
+c$$$      call chainbuild_cart
+c$$$
+c$$$      call geom_to_var(nvar,var)
+c$$$
+c$$$c     Constraints on all angles
+c$$$      do i=1,nvar
+c$$$        tempf=var(i)-orig_ss_var(i)
+c$$$        f=f+tempf*tempf
+c$$$      enddo
+c$$$
+c$$$c     Constraints on all distances
+c$$$      do i=1,nres-1
+c$$$        if (i.gt.1) then
+c$$$          tempf=dist(i+nres,i)-orig_ss_dist(i+nres,i)
+c$$$          f=f+tempf*tempf
+c$$$        endif
+c$$$        do j=i+1,nres
+c$$$          tempf=dist(j,i)-orig_ss_dist(j,i)
+c$$$          if (tempf.lt.0.0D0 .or. j.eq.i+1) f=f+tempf*tempf
+c$$$          tempf=dist(j+nres,i)-orig_ss_dist(j+nres,i)
+c$$$          if (tempf.lt.0.0D0) f=f+tempf*tempf
+c$$$          tempf=dist(j,i+nres)-orig_ss_dist(j,i+nres)
+c$$$          if (tempf.lt.0.0D0) f=f+tempf*tempf
+c$$$          tempf=dist(j+nres,i+nres)-orig_ss_dist(j+nres,i+nres)
+c$$$          if (tempf.lt.0.0D0) f=f+tempf*tempf
+c$$$        enddo
+c$$$      enddo
+c$$$
+c$$$c     Constraints for the relevant CYS-CYS
+c$$$      tempf=dist(nres+ss_i,nres+ss_j)-8.0D0
+c$$$      f=f+tempf*tempf
+c$$$CCCCCCCCCCCCCCCCC      ADD SOME ANGULAR STUFF
+c$$$
+c$$$c$$$      if (nf.ne.nfl) then
+c$$$c$$$        write(iout,'(a,i10,2d15.5)')"IN DIST_FUNC (NF,F,DIST)",nf,
+c$$$c$$$     +       f,dist(5+nres,14+nres)
+c$$$c$$$      endif
+c$$$
+c$$$      nfl=nf
+c$$$
+c$$$      return                                                            
+c$$$      end                                                               
+c$$$
+c$$$C-----------------------------------------------------------------------------
+c$$$C-----------------------------------------------------------------------------
+         subroutine triple_ssbond_ene(resi,resj,resk,eij)
+      include 'DIMENSIONS'
+      include 'COMMON.SBRIDGE'
+      include 'COMMON.CHAIN'
+      include 'COMMON.DERIV'
+      include 'COMMON.LOCAL'
+      include 'COMMON.INTERACT'
+      include 'COMMON.VAR'
+      include 'COMMON.IOUNITS'
+      include 'COMMON.CALC'
+#ifndef CLUST
+#ifndef WHAM
+C      include 'COMMON.MD'
+#endif
+#endif
+
+c     External functions
+      double precision h_base
+      external h_base
+
+c     Input arguments
+      integer resi,resj,resk
+
+c     Output arguments
+      double precision eij,eij1,eij2,eij3
+
+c     Local variables
+      logical havebond
+c      integer itypi,itypj,k,l
+      double precision rrij,ssd,deltat1,deltat2,deltat12,cosphi
+      double precision rrik,rrjk,rik,rjk,xi,xk,yi,yk,zi,zk,xij,yij,zij
+      double precision xik,yik,zik,xjk,yjk,zjk
+      double precision sig0ij,ljd,sig,fac,e1,e2
+      double precision dcosom1(3),dcosom2(3),ed
+      double precision pom1,pom2
+      double precision ljA,ljB,ljXs
+      double precision d_ljB(1:3)
+      double precision ssA,ssB,ssC,ssXs
+      double precision ssxm,ljxm,ssm,ljm
+      double precision d_ssxm(1:3),d_ljxm(1:3),d_ssm(1:3),d_ljm(1:3)
+
+      i=resi
+      j=resj
+      k=resk
+C      write(iout,*) resi,resj,resk
+      itypi=itype(i)
+      dxi=dc_norm(1,nres+i)
+      dyi=dc_norm(2,nres+i)
+      dzi=dc_norm(3,nres+i)
+      dsci_inv=vbld_inv(i+nres)
+      xi=c(1,nres+i)
+      yi=c(2,nres+i)
+      zi=c(3,nres+i)
+
+      itypj=itype(j)
+      xj=c(1,nres+j)
+      yj=c(2,nres+j)
+      zj=c(3,nres+j)
+      
+      dxj=dc_norm(1,nres+j)
+      dyj=dc_norm(2,nres+j)
+      dzj=dc_norm(3,nres+j)
+      dscj_inv=vbld_inv(j+nres)
+      itypk=itype(k)
+      xk=c(1,nres+k)
+      yk=c(2,nres+k)
+      zk=c(3,nres+k)
+      
+      dxk=dc_norm(1,nres+k)
+      dyk=dc_norm(2,nres+k)
+      dzk=dc_norm(3,nres+k)
+      dscj_inv=vbld_inv(k+nres)
+      xij=xj-xi
+      xik=xk-xi
+      xjk=xk-xj
+      yij=yj-yi
+      yik=yk-yi
+      yjk=yk-yj
+      zij=zj-zi
+      zik=zk-zi
+      zjk=zk-zj
+      rrij=(xij*xij+yij*yij+zij*zij)
+      rij=dsqrt(rrij)  ! sc_angular needs rij to really be the inverse
+      rrik=(xik*xik+yik*yik+zik*zik)
+      rik=dsqrt(rrik)
+      rrjk=(xjk*xjk+yjk*yjk+zjk*zjk)
+      rjk=dsqrt(rrjk)
+C there are three combination of distances for each trisulfide bonds
+C The first case the ith atom is the center
+C Energy function is E=d/(a*(x-y)**2+b*(x+y)**2+c) where x is first
+C distance y is second distance the a,b,c,d are parameters derived for
+C this problem d parameter was set as a penalty currenlty set to 1.
+      eij1=dtriss/(atriss*(rij-rik)**2+btriss*(rij+rik)**2+ctriss)
+C second case jth atom is center
+      eij2=dtriss/(atriss*(rij-rjk)**2+btriss*(rij+rjk)**2+ctriss)
+C the third case kth atom is the center
+      eij3=dtriss/(atriss*(rik-rjk)**2+btriss*(rik+rjk)**2+ctriss)
+C      eij2=0.0
+C      eij3=0.0
+C      eij1=0.0
+      eij=eij1+eij2+eij3
+C      write(iout,*)i,j,k,eij
+C The energy penalty calculated now time for the gradient part 
+C derivative over rij
+      fac=-eij1**2/dtriss*(2.0*atriss*(rij-rik)+2.0*btriss*(rij+rik))
+     &-eij2**2/dtriss*(2.0*atriss*(rij-rjk)+2.0*btriss*(rij+rjk))  
+            gg(1)=xij*fac/rij
+            gg(2)=yij*fac/rij
+            gg(3)=zij*fac/rij
+      do m=1,3
+        gvdwx(m,i)=gvdwx(m,i)-gg(m)
+        gvdwx(m,j)=gvdwx(m,j)+gg(m)
+      enddo
+      do l=1,3
+        gvdwc(l,i)=gvdwc(l,i)-gg(l)
+        gvdwc(l,j)=gvdwc(l,j)+gg(l)
+      enddo
+C now derivative over rik
+      fac=-eij1**2/dtriss*(-2.0*atriss*(rij-rik)+2.0*btriss*(rij+rik))
+     &-eij3**2/dtriss*(2.0*atriss*(rik-rjk)+2.0*btriss*(rik+rjk))
+            gg(1)=xik*fac/rik
+            gg(2)=yik*fac/rik
+            gg(3)=zik*fac/rik
+      do m=1,3
+        gvdwx(m,i)=gvdwx(m,i)-gg(m)
+        gvdwx(m,k)=gvdwx(m,k)+gg(m)
+      enddo
+      do l=1,3
+        gvdwc(l,i)=gvdwc(l,i)-gg(l)
+        gvdwc(l,k)=gvdwc(l,k)+gg(l)
+      enddo
+C now derivative over rjk
+      fac=-eij2**2/dtriss*(-2.0*atriss*(rij-rjk)+2.0*btriss*(rij+rjk))-
+     &eij3**2/dtriss*(-2.0*atriss*(rik-rjk)+2.0*btriss*(rik+rjk))
+            gg(1)=xjk*fac/rjk
+            gg(2)=yjk*fac/rjk
+            gg(3)=zjk*fac/rjk
+      do m=1,3
+        gvdwx(m,j)=gvdwx(m,j)-gg(m)
+        gvdwx(m,k)=gvdwx(m,k)+gg(m)
+      enddo
+      do l=1,3
+        gvdwc(l,j)=gvdwc(l,j)-gg(l)
+        gvdwc(l,k)=gvdwc(l,k)+gg(l)
+      enddo
+      return
+      end