SUBROUTINE DZBREN(F,ERRABS,ERRREL,A,B,MAXFN)
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
      EXTERNAL F
      CALL ZBRENT(F,A,B,ZERO,ERRABS,ERRREL,MAXFN,ITER1)
      B=ZERO
      MAXFN=ITER1
      RETURN
      END