SUBROUTINE SUSARR( ierr )
C ----------------------------------------------------------------------
C  Purpose: Integrate total cross-section.
C           DIVON4 integration package is used. 
C
C   Author: JMB
C ----------------------------------------------------------------------
C
      IMPLICIT NONE
C
      INCLUDE 'SUSANA.INC'
      INCLUDE 'PYTHIA57.INC'
C
      DOUBLE PRECISION dfun, factor, xyh(2), xyl(2), xypeak(2)
      REAL xsd, step, errmax
      INTEGER IErr, maxnum
      REAL ulmass
      EXTERNAL ulmass
C
C
C --  Set function type.
      Function_type = 1
C
C --  Integration parameters.
      maxnum = 100000
C
C --  Partition cross section.
      CALL PARTN( 2, low, high, 1.0, maxnum)
      CALL INTGRL( 2, 0, isustr(4), total_xsec, error_xsec)
C
C --  Reset function type.
      Function_type = 0
C
C --  Convert the total cross-section (at present in GeV^-2) to picobarns.
      factor = (0.197**2) * 1.0E+10
      total_xsec = total_xsec * factor 
      error_xsec  = error_xsec * factor 
      WRITE( isustr(1),1000) total_xsec, error_xsec
C
C
C --  Add beam particles to the LUND list.
C     Electron.
      k(1,1) = 21
      k(1,2) = 11
      p(1,1) = pl(1)
      p(1,2) = pl(2)
      p(1,3) = PL(3)
      p(1,4) = SQRT( PL(4)**2 + ULMASS(11)**2 )
      p(1,5) = ULMASS(11)
C     Proton.
      k(2,1) = 21
      k(2,2) = 2212
      p(2,1) = pp(1)
      p(2,2) = pp(2)
      p(2,3) = pp(3)
      p(2,4) = SQRT( PP(4)**2 + ULMASS(2212)**2 )
      p(2,5) = ULMASS(2212)
C
 8900 CONTINUE
      RETURN
C
 1000 FORMAT(//,18X,'Total Cross-section = ', E8.2, '+-'
     &,       E8.2,' pb', /)
      END