anchor.diff:  c~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   c
   c
  -      subroutine load(id,ibond,bond,d,deld,b,histry,deltp,ndof,numnp,
  -     & neq,nhist,nstep,lastep,idout,kto,kw)
  +      subroutine load(id,ibond,bond,d,deld,b,histry,deltp,numnp,
  +     & neq,nhist,nstep,lastep,ierr,errstrng)
   c
   c...program to transfer nodal boundary conditions into appropriate
   c   vectors:
  
positive.code: c
        include "implicit.inc"
  c
  c...  subroutine arguments
  c
        integer ndof,numnp,neq,nhist,nstep,lastep,idout,kto,kw
        integer id(ndof,numnp),ibond(ndof,numnp)
        double precision bond(ndof,numnp),b(neq),d(ndof,numnp)
        double precision deld(ndof,numnp),histry(nhist,lastep+1),deltp
  c
  c...  defined constants
  c
        include "rconsts.inc"
  c
  c...  local variables
  c
  
negative.code:           ihist=imode/10
            itype=imode-10*ihist
  c*          write(6,"(3i7)") imode,ihist,itype
            if((ihist.gt.nhist).or.(ihist.lt.izero)) then
              ierr=100
              errstrng="load"
              return
            end if
  c
  c...specified displacment, condition 1
  c
            if(itype.eq.ione) then
              if(nstep.eq.izero) then
                d(i,j)=bond(i,j)
                if(ihist.ne.izero) d(i,j)=bond(i,j)*histry(ihist,1)
              else if(nstep.ge.ione) then
                if(ihist.ne.izero) deld(i,j)=bond(i,j)*
       &         (histry(ihist,nstep+1)-histry(ihist,nstep))
              end if
  c
  c...specified velocity, condition 2
  c
            else if(itype.eq.itwo) then
              if(nstep.eq.izero) then
                d(i,j)=zero
              else
                deld(i,j)=deltp*bond(i,j)
                if(ihist.ne.izero) deld(i,j)=deld(i,j)*
       &         histry(ihist,nstep+1)
              end if
  c
  c...applied force, condition 3
  c
            else if(itype.eq.ithree) then
              k=id(i,j)
              if(nstep.eq.izero) then
                b(k)=bond(i,j)
                if(ihist.ne.izero) b(k)=bond(i,j)*histry(ihist,1)
              else if(nstep.ge.ione) then
                if(ihist.ne.izero) b(k)=bond(i,j)*(histry(ihist,nstep+1)
       &                                 -histry(ihist,nstep))
              end if
            end if
  