psblas3/base/serial/aux/ibsrch.f

C
C             Parallel Sparse BLAS  v2.0
C   (C) Copyright 2006 Salvatore Filippone    University of Rome Tor Vergata
C                      Alfredo Buttari        University of Rome Tor Vergata
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C 
      subroutine ibsrch(ipos,key,n,v)
      integer ipos, key, n
      integer v(n)
      
      integer lb, ub, m
      
      
      lb = 1 
      ub = n
      ipos = -1 
      
      do while (lb.le.ub) 
        m = (lb+ub)/2
        if (key.eq.v(m))  then
          ipos = m 
          lb   = ub + 1
        else if (key.lt.v(m))  then
          ub = m-1
        else 
          lb = m + 1
        end if
      enddo
      return
      end