Incompatible ranks 0 and 2 in assignment

Question

I have tried to write a code in fortran to calculate the coordination number. But a got these errors

 coord.f:43.72:

            read(13,*) ri(i),  g(2,2,i),   g(1,2,i),   g(1,2,i),    g(1,
                                                                        1
Error: Expected array subscript at (1)
coord.f:78.38:

          call integrate(npts-1,ri,gt,ans)                              
                                      1
Warning: Rank mismatch in argument 'ans' at (1) (scalar and rank-2)
coord.f:79.8:

        t1(ia,ib)=ans                                                   
        1
Error: Incompatible ranks 0 and 2 in assignment at (1)
coord.f:52.32:

      call coordination(ri,g,ro,num)                                    
                                1
Warning: Invalid procedure argument at (1)

This is the code below which I have tried for it. Can anyone please help me to solve these errors?

ccccc   Solution for Coordination number: 

c   2 :macro-ion
c   1 :counter-ion

        include "prmts" ! parameter for npts, l, pi, bl!
        character init*10

        integer icont(l,l)
        double precision grid, dm22, dr, dt, num 
        double precision g(l,l,npts),
     &  ro(l,l),z(l),r(l),ri(npts),dm(l,l), 
     &  h(l,l,npts),ans(l,l), t1(l,l),gt(npts)

        open(unit=13,file='grm.out.txt',status='old')
        open(unit=14,file='cor.out',status='unknown')

         read(13,*)(z(i),i=1,l)  ! algebric charge  !
         read(13,*)(r(i),i=1,l)  ! radious of ions  !
         read(13,*)ro(2,2)   ! no.density of 2  !               
        do i = 1, l
          r(i) = r(i)
        enddo
        dm22 = dm22
        dr = r(2)/grid
        ro(2,2) = ro(2,2)
        ro(1,1) = -z(2)*ro(2,2)/z(1)
                   ! From condition of electro neutrality !


        open(unit=13,file='grm.out.txt',status='old')
         do i=1, npts-1
            read(13,*) ri(i),  g(2,2,i),   g(1,2,i),   g(1,2,i),    g(1,1,i)
         enddo     
        close(13)

CCCCC   CALCULATE COORDINATION NUMBER

        call coordination(ri,g,ro,num)

        write(14,*)"# Cornum = ", num(ia,ib) 
        write(14,*)"#----------------------------------------------"
        write(14,*)"#   num22   num21   num12  num11    "
        write(14,*)"#----------------------------------------------" 
999 format( 4f18.6)

        stop
        end    ! end of main !


        subroutine coordination(ri,g,ro,num)
        include 'prmts' ! for l, npts, pi and bl !
        double precision ri(npts), g(l,l,npts), ro(l,l)
     &  , num(l,l), ans(l,l), t1(l,l),gt(npts)
        integer i, ia, ib

CCCCC   COORDINATION NUMBER
CCCCC   Cornum : Coordination number.

        do ia=1,l
        do ib=1,l
        do i=1,npts-1
          gt(i)=g(ia,ib,i)*ri(i)**2
        enddo
          call integrate(npts-1,ri,gt,ans)
          t1(ia,ib)=ans
        enddo
        enddo

CCCCC   COORDINATION NUMBER

        do ia=1,l
        do ib=1,l
          num(ia,ib)= 4.0d0*pi*ro(ib,ib)*t1(ia,ib)
        enddo
        enddo
        write(*,*) 'Cornum = ', num(ia,ib)
        end

      subroutine integrate(n,x,y,ans)
      integer          nin, nout
      parameter        (nin=5,nout=6)
      double precision ans, error
      integer          ifail, n
      double precision x(n), y(n)
         ifail = 1

         call pintegr(x,y,n,ans,error,ifail)

         if (ifail.eq.0) then
            write (nout,99999) 'integral = ', ans,
     +        '     estimated error = ', error
         else if (ifail.eq.1) then
            write (nout,*) 'less than 4 points supplied'
         else if (ifail.eq.2) then
            write (nout,*)
     +        'points not in increasing or decreasing order'
         else if (ifail.eq.3) then
            write (nout,*) 'points not all distinct'
         end if
      return

99999 format (1x,a,e12.4,a,e12.4)
      end

      subroutine pintegr(x,y,n,ans,er,ifail)
      double precision  ans, er
      integer n
      double precision  x(n), y(n)
      double precision c, d1, d2, d3, h1, h2, h3, h4, r1, r2, r3, 
     * r4, s
      integer i, nn
      ans = 0.0d0
      er = 0.0d0
      if (n.ge.4) go to 20
      ifail = 1
      return
        h2 = x(2) - x(1)  20
        do 80 i = 3, n
         h3 = x(i) - x(i-1)
         if (h2*h3) 40, 40, 80
        write(*,*)'points not specified correctly'        40
         ifail = 3
         return
     continue         80

      d3 = (y(2)-y(1))/h2
      h3 = x(3) - x(2)
      d1 = (y(3)-y(2))/h3
      h1 = h2 + h3
      d2 = (d1-d3)/h1
      h4 = x(4) - x(3)
      r1 = (y(4)-y(3))/h4
      r2 = (r1-d1)/(h4+h3)
      h1 = h1 + h4
      r3 = (r2-d2)/h1
      ans = h2*(y(1)+h2*(d3/2.0d0-h2*(d2/6.0d0-(h2+2.0d0*h3)*r3/12.0d0))
     *      )
      s = -(h2**3)*(h2*(3.0d0*h2+5.0d0*h4)+10.0d0*h3*h1)/60.0d0
      r4 = 0.0d0

      nn = n - 1
      do 120 i = 3, nn
         ans = ans + h3*((y(i)+y(i-1))/2.0d0-h3*h3*(d2+r2+(h2-h4)*r3)
     *         /12.0d0)
         c = h3**3*(2.0d0*h3*h3+5.0d0*(h3*(h4+h2)+2.0d0*h4*h2))/120.0d0
         er = er + (c+s)*r4
         if (i.ne.3) s = c
         if (i.eq.3) s = s + 2.0d0*c
         if (i-n+1) 100, 140, 100
         h1 = h2                   100
         h2 = h3
         h3 = h4
         d1 = r1
         d2 = r2
         d3 = r3
         h4 = x(i+2) - x(i+1)
         r1 = (y(i+2)-y(i+1))/h4
         r4 = h4 + h3
         r2 = (r1-d1)/r4
         r4 = r4 + h2
         r3 = (r2-d2)/r4
         r4 = r4 + h1
         r4 = (r3-d3)/r4
       continue       120

       continue       140
          ans = ans + h4*(y(n)-h4*(r1/2.0d0+h4*(r2/6.0d0+(2.0d0*h3+h4)
         *      *r3/12.0d0)))
           er = er - h4**3*r4*(h4*(3.0d0*h4+5.0d0*h2)+10.0d0*h3*(h2+h3+h4))
         *     /60.0d0 + s*r4
           ans = ans + er
           ifail = 0
            return
           end

END of Program

Answer 1

The key is to notice that the first error is at column 72 and that the line is incomplete in the error message.

The line is to long for Fortran 77 which allows only 72 characters. Divide the lines into to or use some compiler option to allow longer lines (breaks portability).

There are other errors too, like

t1(ia,ib)=ans

t1(ia,ib) is a scalar (one array element) and ans is an array. That is not possible, you must be consistent.

The procedure integrate defines its dummy argument ans as a scalar real due to implicit typing, but you pass an array ans to it. That is also not possible.

I suggest you to use implicit none in all programs although it is technically not Fortran 77. It will help you to avoid many errors.

Finally, num was declared as as double precision but used as

num(ia,ib)

for this reason the compiler thinks it is an external function and warns you about the invalid procedure argument. You must be consistent and declare it as an array or use it as a scalar.

Probably, there are many more errors in the code, it is quite messy and very hard to read.