SUBROUTINE get_erange
USE Numeric_Kinds_Module
USE CommonInfo_Module
USE APH_Module
USE Aph_Ham_Module
USE SurfaceAph_Module
USE Cheby_Module
USE SymGroup_Module
USE Masses_Module
USE Convrsns_Module
IMPLICIT NONE
!==============================================================================
! Diagonalize kinetic energy operators. Chi and theta eigenvectors will
! be used 
! to reduce the maximum aggregate eigenvalue.
! Assign energy bounds for chebychev propagation.
!==============================================================================

INTEGER :: i, iir, nchir


  first_theta=.true.
  clip_theta=.true.

  ALLOCATE( rho_eig(nrho) , rho_evec(nrho,nrho) )
  ALLOCATE( tht_eig(ntheta) , tht_evec(ntheta,ntheta) , weights(ntheta))
  ALLOCATE( compr2(ntheta, ntheta), compr_mat2(ntheta, ntheta, ntheta) )
  ALLOCATE( tempvcut2(ntheta,ntheta), tempeig2(ntheta,ntheta) )
  ALLOCATE( t_theta_clip(ntheta,ntheta),  num_eig2(nrho) )

 ! RHO
 ! ========================================================================
 CALL diag_out(nrho, t_rho,rho_val,deltarho,1.d0,rho_eig,rho_evec,'rho')
 eigmax=rho_eig(nrho)

 ! THETA
 ! ======================================================================
 ! weights determined by matching ground state to 1/Sqrt(2)
 IF (ntheta.gt.1) THEN
   CALL diag_out(ntheta, t_theta, theta_val, 1.d0, 1.d0, tht_eig,tht_evec, 'theta')

   Do i=1,ntheta
     weights(i)=2.d0*tht_evec(i,1)*tht_evec(i,1)
   Enddo

   IF (clip_theta) THEN
     eigmax=eigmax+vcut
   ELSE
     eigmax=eigmax+(tht_eig(ntheta)*rhom2(1))
   ENDIF
 ELSE
   weights(1)=1.d0
 ENDIF

! CHI ========================================================================
 ! No need to diagonalize yet, eigmax will be set to vcut
 ! Create array that provides the location of each irreducible representaion 
 ! block.

 ALLOCATE(indexchi_array(nirrep))
 indexchi_array(1)=0
 DO iir=1,nirrep-1
   nchir=nchi_ir(iir)
   indexchi_array(iir+1)=indexchi_array(iir)+nchir
 ENDDO

   eigmax=eigmax+vcut+vcut+((15.d0*rhom2(1))/(4.d0*usys2))
   eigmin=0.d0

!==============================================================================
! Write max eigenvalue information
!------------------------------------------------------------------------------

  WRITE(Out_Unit,71) 'Eigenvalue Info:','au','eV'
  WRITE(Out_Unit,72) 'rho eigmax', rho_eig(nrho), rho_eig(nrho)*autoev
  WRITE(Out_Unit,72) 'tht eigmax', tht_eig(ntheta)*rhom2(1),           &
                                   tht_eig(ntheta)*rhom2(1)*autoev
  WRITE(Out_Unit,72) 'chi eigmax', vcut, vcut*autoev
  WRITE(Out_Unit,72) 'vcut      ', vcut, vcut*autoev
  WRITE(Out_Unit,72) 'total     ', eigmax, eigmax*autoev
  71 FORMAT (/1X,a,T24,a,T34,a,/1X,50('-'))
  72 FORMAT (1X,a,10('.'),f7.4,3X,f7.3)
  73 FORMAT (1X,a,10('.'),f10.7,3X,f10.7)

DEALLOCATE(rho_eig, rho_evec)

END SUBROUTINE get_erange