Computational routine
eng

##
rndblk

### File content

          subroutine rndblk(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
    c     ipar(1)
    c            0 : uniform
    c            1 : normal
    c     rpar(1:ny)=mean
    c     rpar(ny+1:2*ny)=deviation
    c     rpar(2*ny+1)=dt
    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 urand,sr,si,t1

          integer halt
          common /coshlt/ halt
    c
          if(flag.eq.1.or.flag.eq.6) then
          do 10 i=1,ny
             y(i)=rpar(i)+rpar(ny+i)*z(i+1)
     10   continue
          elseif(flag.eq.2.or.flag.eq.4) then
    c     uniform
             if(ipar(1).eq.0) then
                iy=int(z(1))
                do 20 i=1,nz-1
                   z(i+1)=urand(iy)
     20         continue
             else
                iy=int(z(1))
    c     normal
                do 30 i=1,nz-1
     75            sr=2.0d+0*urand(iy)-1.0d+0
                   si=2.0d+0*urand(iy)-1.0d+0
                   t1 = sr*sr+si*si
                   if (t1 .gt. 1.0d+0) go to 75
                   z(i+1) = sr*sqrt(-2.0d+0*log(t1)/t1)
     30         continue
             endif
             z(1)=iy
    c         if(ntvec.eq.1) tvec(1)=t+rpar(2*(nz-1)+1)
          endif
          return
          end