subroutine check_ecartint
! Check the gradient of the energy in Cartesian coordinates. 
      implicit none
      include 'DIMENSIONS'
      include 'COMMON.CONTROL'
      include 'COMMON.CHAIN'
      include 'COMMON.INTERACT'
      include 'COMMON.DERIV'
      include 'COMMON.IOUNITS'
      include 'COMMON.VAR'
      include 'COMMON.CONTACTS'
      include 'COMMON.MD'
      include 'COMMON.LOCAL'
      include 'COMMON.SPLITELE'
      integer icall
      common /srutu/ icall
      double precision ggg(6),ggg1(6),cc(3),xx(3),ddc(3),ddx(3),
     & x(maxvar),g(maxvar)
      double precision dcnorm_safe(3),dxnorm_safe(3)
      double precision grad_s(6,0:maxres),grad_s1(6,0:maxres)
      double precision phi_temp(maxres),theta_temp(maxres),
     &  alph_temp(maxres),omeg_temp(maxres)
      double precision ddc1(3),ddcn(3),dcnorm_safe1(3),dcnorm_safe2(3)
      double precision energia(0:n_ene),energia1(0:n_ene)
      integer uiparm(1)
      double precision urparm(1)
      double precision fdum
      external fdum
      integer i,j,k,nf
      double precision etot,etot1,etot2,etot11,etot12,etot21,etot22
      double precision dist,alpha,beta
      icg=1
      nf=0
      nfl=0
      call intout
!      call intcartderiv
!      call checkintcartgrad
      call zerograd
      aincr=1.0D-5
      write(iout,*) 'Calling CHECK_ECARTINT.'
      nf=0
      icall=0
      write (iout,*) "Before geom_to_var"
      call geom_to_var(nvar,x)
      write (iout,*) "after geom_to_var"
      write (iout,*) "split_ene ",split_ene
      call flush(iout)
      if (.not.split_ene) then
        write(iout,*) 'Calling CHECK_ECARTINT if'
        call etotal(energia)
!elwrite(iout,*) 'Calling CHECK_ECARTINT if'
        etot=energia(0)
        write (iout,*) "etot",etot
        call enerprint(energia(0))
        call flush(iout)
!el        call enerprint(energia)
!elwrite(iout,*) 'Calling CHECK_ECARTINT if'
c        call flush(iout)
c        write (iout,*) "enter cartgrad"
c        call flush(iout)
        call cartgrad
c Transform the gradient to the CA-SC basis
        call grad_transform
!elwrite(iout,*) 'Calling CHECK_ECARTINT if'
c        write (iout,*) "exit cartgrad"
c        call flush(iout)
        icall =1
c        do i=1,nres
c          write (iout,'(i5,3f10.5)') i,(gradxorr(j,i),j=1,3)
c        enddo
        do j=1,3
          grad_s(j,0)=gcart(j,0)
        enddo
!elwrite(iout,*) 'Calling CHECK_ECARTINT if'
        do i=1,nres
          do j=1,3
            grad_s(j,i)=gcart(j,i)
            grad_s(j+3,i)=gxcart(j,i)
          enddo
        enddo
      else
c        write(iout,*) 'Calling CHECK_ECARTIN else.'
!- split gradient check
        call zerograd
        call etotal_long(energia)
        call enerprint(energia(0))
!el        call enerprint(energia)
c        call flush(iout)
c        write (iout,*) "enter cartgrad"
c        call flush(iout)
        call cartgrad
c Transform the gradient to CA-SC coordinates
        call grad_transform
c        write (iout,*) "exit cartgrad"
c        call flush(iout)
        icall =1
        write (iout,*) "longrange grad"
        do i=1,nres
          write (iout,'(i5,3f10.5,5x,3f10.5)') i,(gcart(j,i),j=1,3),
     &    (gxcart(j,i),j=1,3)
        enddo
        do j=1,3
          grad_s(j,0)=gcart(j,0)
        enddo
        do i=1,nres
          do j=1,3
            grad_s(j,i)=gcart(j,i)
            grad_s(j+3,i)=gxcart(j,i)
          enddo
        enddo
        call zerograd
        call etotal_short(energia)
        call enerprint(energia(0))
        call flush(iout)
c        write (iout,*) "enter cartgrad"
c        call flush(iout)
        call cartgrad
c        write (iout,*) "exit cartgrad"
c        call flush(iout)
c Transform the gradient to CA-SC basis
        call grad_transform
        icall =1
        write (iout,*) "shortrange grad"
        do i=1,nres
          write (iout,'(i5,3f10.5,5x,3f10.5)') i,(gcart(j,i),j=1,3),
     &    (gxcart(j,i),j=1,3)
        enddo
        do j=1,3
          grad_s1(j,0)=gcart(j,0)
        enddo
        do i=1,nres
          do j=1,3
            grad_s1(j,i)=gcart(j,i)
            grad_s1(j+3,i)=gxcart(j,i)
          enddo
        enddo
      endif
      write (iout,'(/a/)') 'Gradient in virtual-bond and SC vectors'
!      do i=1,nres
c      do i=nnt,nct
      do i=1,nres
        do j=1,3
          if (nnt.gt.1 .and. i.eq.nnt) ddc1(j)=c(j,1)
          if (nct.lt.nres .and. i.eq.nct) ddcn(j)=c(j,nres)
	  ddc(j)=c(j,i) 
	  ddx(j)=c(j,i+nres) 
          dcnorm_safe1(j)=dc_norm(j,i-1)
          dcnorm_safe2(j)=dc_norm(j,i)
          dxnorm_safe(j)=dc_norm(j,i+nres)
        enddo
	do j=1,3
	  c(j,i)=ddc(j)+aincr
          if (nnt.gt.1 .and. i.eq.nnt) c(j,1)=c(j,1)+aincr
          if (nct.lt.nres .and. i.eq.nct) c(j,nres)=c(j,nres)+aincr
          if (i.gt.1) dc(j,i-1)=c(j,i)-c(j,i-1)
          dc(j,i)=c(j,i+1)-c(j,i)
          dc(j,i+nres)=c(j,i+nres)-c(j,i)
          call int_from_cart1(.false.)
          if (.not.split_ene) then
            call etotal(energia1)
            etot1=energia1(0)
c            write (iout,*) "ij",i,j," etot1",etot1
          else
!- split gradient
            call etotal_long(energia1)
            etot11=energia1(0)
            call etotal_short(energia1)
            etot12=energia1(0)
          endif
!- end split gradient
!          write(iout,'(2i5,2(a,f15.10))')i,j," etot",etot," etot1",etot1
	  c(j,i)=ddc(j)-aincr
          if (nnt.gt.1 .and. i.eq.nnt) c(j,1)=ddc1(j)-aincr
          if (nct.lt.nres .and. i.eq.nct) c(j,nres)=ddcn(j)-aincr
          if (i.gt.1) dc(j,i-1)=c(j,i)-c(j,i-1)
          dc(j,i)=c(j,i+1)-c(j,i)
          dc(j,i+nres)=c(j,i+nres)-c(j,i)
          call int_from_cart1(.false.)
          if (.not.split_ene) then
            call etotal(energia1)
            etot2=energia1(0)
c            write (iout,*) "ij",i,j," etot2",etot2
	    ggg(j)=(etot1-etot2)/(2*aincr)
          else
!- split gradient
            call etotal_long(energia1)
            etot21=energia1(0)
	    ggg(j)=(etot11-etot21)/(2*aincr)
            call etotal_short(energia1)
            etot22=energia1(0)
	    ggg1(j)=(etot12-etot22)/(2*aincr)
!- end split gradient
!            write (iout,*) "etot21",etot21," etot22",etot22
          endif
!          write(iout,'(2i5,2(a,f15.10))')i,j," etot",etot," etot2",etot2
	  c(j,i)=ddc(j)
          if (nnt.gt.1 .and. i.eq.nnt) c(j,1)=ddc1(j)
          if (nct.lt.nres .and. i.eq.nct) c(j,nres)=ddcn(j)
          if (i.gt.1) dc(j,i-1)=c(j,i)-c(j,i-1)
          dc(j,i)=c(j,i+1)-c(j,i)
          dc(j,i+nres)=c(j,i+nres)-c(j,i)
          dc_norm(j,i-1)=dcnorm_safe1(j)
          dc_norm(j,i)=dcnorm_safe2(j)
          dc_norm(j,i+nres)=dxnorm_safe(j)
        enddo
	do j=1,3
	  c(j,i+nres)=ddx(j)+aincr
          dc(j,i+nres)=c(j,i+nres)-c(j,i)
          call int_from_cart1(.false.)
          if (.not.split_ene) then
            call etotal(energia1)
            etot1=energia1(0)
          else
!- split gradient
            call etotal_long(energia1)
            etot11=energia1(0)
            call etotal_short(energia1)
            etot12=energia1(0)
          endif
!- end split gradient
	  c(j,i+nres)=ddx(j)-aincr
          dc(j,i+nres)=c(j,i+nres)-c(j,i)
          call int_from_cart1(.false.)
          if (.not.split_ene) then
            call etotal(energia1)
            etot2=energia1(0)
	    ggg(j+3)=(etot1-etot2)/(2*aincr)
          else
!- split gradient
            call etotal_long(energia1)
            etot21=energia1(0)
	    ggg(j+3)=(etot11-etot21)/(2*aincr)
            call etotal_short(energia1)
            etot22=energia1(0)
	    ggg1(j+3)=(etot12-etot22)/(2*aincr)
!- end split gradient
          endif
!          write(iout,'(2i5,2(a,f15.10))')i,j," etot",etot," etot2",etot2
	  c(j,i+nres)=ddx(j)
          dc(j,i+nres)=c(j,i+nres)-c(j,i)
          dc_norm(j,i+nres)=dxnorm_safe(j)
          call int_from_cart1(.false.)
        enddo
	write (iout,'(i3,6(1pe12.5)/3x,6(1pe12.5)/3x,6(1pe12.5)/)') 
     &   i,(ggg(k),k=1,6),(grad_s(k,i),k=1,6),(ggg(k)/grad_s(k,i),k=1,6)
        if (split_ene) then
          write (iout,'(i3,6(1pe12.5)/3x,6(1pe12.5)/3x,6(1pe12.5)/)') 
     &   i,(ggg1(k),k=1,6),(grad_s1(k,i),k=1,6),(ggg1(k)/grad_s1(k,i),
     &   k=1,6)
         write (iout,'(i3,6(1pe12.5)/3x,6(1pe12.5)/3x,6(1pe12.5)/)') 
     &   i,(ggg(k)+ggg1(k),k=1,6),(grad_s(k,i)+grad_s1(k,i),k=1,6),
     &   ((ggg(k)+ggg1(k))/(grad_s(k,i)+grad_s1(k,i)),k=1,6)
        endif
      enddo
      return
      end