lookup
subroutine lookup(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,
& rpar,nrpar,ipar,nipar,u,nu,y,ny)
c Copyright INRIA
c Scicos block simulator
c rpar(1:n) = u coordinate discretisation must be strictly increasing
c rpar(n+1:2*n) = y coordinate discretisation
c
double precision t,xd(*),x(*),z(*),tvec(*),rpar(*),u(*),y(*)
integer flag,nevprt,nx,nz,ntvec,nrpar,ipar(*)
integer nipar,nu,ny
c
double precision du,dout
integer i
c
n=nrpar/2
if(n.gt.2) then
do 10 i=2,n-1
if (u(1).le.rpar(i)) goto 20
10 continue
else
if(n.eq.1) then
y(1)=rpar(2)
return
endif
i=2
endif
20 continue
du=rpar(i)-rpar(i-1)
dout=rpar(n+i)-rpar(n+i-1)
y(1)=rpar(n+i)-(rpar(i)-u(1))*dout/du
end