Computational routine
eng

##
delayv

### File content

          subroutine delayv(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,
         &     rpar,nrpar,ipar,nipar,u1,nu1,u2,nu2,y,ny)
    c     Copyright INRIA

    c     rpar(1)=dt
    c     delayv=u(nin)
    c
          double precision t,xd(*),x(*),z(*),tvec(*),rpar(*),y(*)
          double precision u1(*),u2(*)
          integer flag,nevprt,nx,nz,ntvec,nrpar,ipar(*)
          integer nipar,nu1,nu2,ny

          double precision a,dtat,u2r
          integer i,in,j,k

          j=int((nz-1)/nu1)
          if(flag.eq.3) then
             tvec(1)=t+rpar(1)
             k=int(u2(1)/rpar(1))
             if(k.gt.(j-3)) tvec(2)=t
             if(k.lt.1) tvec(2)=t
          endif
    c
    c     .   shift buffer
          if(flag.eq.2) then
             do 10 i=1,j
                z(i)=z(i+1)
     10      continue
             do 30 in=1,nu1-1
                do 35 ii=(in*j)+1,(in+1)*j
                   z(ii)=z(ii+1)
     35         continue
     30      continue
             z(nz)=t

             do 20 in=1,nu1
                z(j*in)=u1(in)
     20      continue
          endif

          if(flag.eq.1.or.flag.eq.6) then
             dtat=t-z(nz)
             do 08 in=1,nu1
    c     extrapolate to find values at delta.t
                if(u2(1).le.dtat) then
    c     initialisation start
                   if(dtat.lt.rpar(1)/100.0d0) then
                      a=u2(1)/(rpar(1)+dtat)
    c     delete negative delay
                      if(a.le.(0.0d0)) a=0.0d0
                      y(in)=(1-a)*z(j*in)+a*z((j*in)-1)
                   else
                      a=u2(1)/dtat
    c     delete negative delay
                      if(a.le.(0.0d0)) a=0.0d0
                      y(in)=(1-a)*u1(in)+a*z(j*in)
                   endif
                else
                   u2r=(u2(1)-dtat)
                   k=int(u2r/rpar(1))
    c     limitation of size buffer
                   if(k.gt.(j-3)) then
                      k=j-3
                      a=1.0d0
                   else
                      a=(u2r-(k*rpar(1)))/rpar(1)
                   endif
    c     interpolate to find values at t-delay
                   y(in)=(1-a)*z((j*in)-k)+a*z((j*in)-k-1)
                endif
     08      continue

          endif
          return
          end