FORTRAN 90 Unexpected Statement Function Statement in Nested Do Loop

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Discussion Overview

The discussion revolves around a FORTRAN 90 code snippet that generates a cumulative emissions curve using nested DO loops. Participants are addressing an error related to the use of a statement function and issues with variable declarations and data types.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant reports an "Unexpected STATEMENT FUNCTION statement" error related to the variable "sum" in the line "cem(i) = sum".
  • Another participant suggests renaming the variable "sum" to avoid collision with an intrinsic function.
  • Concerns are raised about the declaration of "cem()" as an array, with one participant noting it is being used as an array but not declared as such.
  • A participant identifies a potential issue with the read statement, indicating that "year" and "emissions" are being read as one-dimensional arrays but are later treated as scalar entities.
  • One participant reiterates the issue regarding the declaration of "cem()" as an array.

Areas of Agreement / Disagreement

Participants express agreement on the issues related to variable declarations and the read statement, but there is no consensus on the best approach to resolve the "Unexpected STATEMENT FUNCTION statement" error.

Contextual Notes

There are unresolved issues regarding the proper declaration of variables and the handling of data types, which may affect the execution of the code.

tch2
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In the following code, highlighted in bold, I am using a nested DO loop to create a running sum of the yearly emissions ("emissions") read out of histem.txt, to create a cumulative emissions curve.

The code generates an "Unexpected STATEMENT FUNCTION statement for sum in cem(i) = sum, however?

Code:
program sat_profile

! This program can be used to create a smooth temperature profile starting from
! a specified slope at the year 2005 and stabilizing (with zero slope) at 2300.
! The starting slope can be calculated from the last 10 years of the simulation
! providing the initial condition at 2005. A starting temperature and final 
! temperature also need to be specified. The final target temperature should be
! the modeled preindustrial temperature plus the temperature target (1.5, 2, 3, 
! and 4 degrees C). An arbitrary mid point year and temperature (between 2005 
! and 2300) is also specified. This may need some adjustment in order to 
! generate a smoothly changing profile without overshoot. The output is a text 
! file with annual values from 2005 to 2500. This can be adjusted to provide 
! interpolated values at other time intervals by changing the loop that 
! generates tval and calculates yval. 
 
 implicit none

  integer, parameter :: nd=3, iyr=2008, fyr = 2500
  integer i, j
  real t(nd), y(nd), ypp(nd), tval, yval, ypval, yppval, ybcbeg, ybcend, offset, initg
  
  real year(257), emissions(257), HIST, TIM, sum, cem
  
  
  real AEMIT(iyr:fyr), EMIT(iyr:fyr), TIME(iyr:fyr)

! input parameters: NOTE --> t(1) and t(3) MUST match iyr and fyr respectively
  t(1) = 2008.               ! starting year of synthetic profile
  t(3) = 2500.               ! year of zero emissions
  t(2) = 2400.               ! year of peak emissions (may be adjusted)
  y(1) = 346.758            ! emissions at starting year (set to year 2008)
  y(3) = 2000          ! emissions at end (set to PI + target)
  y(2) = 1900      ! emissions at peak (may be adjusted)
! starting slope can be derived from the last 10 years of a simulation to 2008
  initg =  8.749	     ! value of EMIT(t=1) (should be the same as 2008 annual emissions in historical curve)
  ybcbeg = 8.749           ! slope at t(1) (Gt year-1)
  ybcend = 0.                ! slope at t(3) (zero)
  offset = 0               ! time offset (half of the averaging period)
! calculate the spline derivatives
  call spline_cubic_set ( nd, t, y, 1, ybcbeg, 1, ybcend, ypp )


if (t(3).lt.t(2)) then 
print *, 'error, t(2) must be smaller than t(3)'
call exit(1)
endif

if (t(3).eq.t(2)) then
print *, 'error, t(2) must be smaller than t(3)'
call exit(1)
endif

if (iyr.ne.t(1)) then 
print *, 'error, iyr and t(1) do not match'
call exit(1)
endif


if (fyr.ne.t(3)) then 
print *, 'error, fyr and t(3) do not match'
call exit(1)
endif


open(unit=15, file='histem.txt')
read(15,*,end=258) year, emissions

258 open (10, file='cumemC.txt')
! evaluate the spline at points tval
  
!change 2005, 2500 to values of t(1) and t(3)

[B]do i=1,257
sum=0
     do j=1,i
     sum = sum + emissions(j)
     write (*, '(2f12.4)') 
     enddo
cem(i) = sum   
write (10, '(2f12.4)') year(i), cem(i)
enddo [/B] 

do i=iyr,fyr
    tval = float(i)
    call spline_cubic_val ( nd, t, y, ypp, tval, yval, ypval, yppval )

! if not doing stabilization, get rid of this line:    
    !if (tval > t(3)) yval = y(3)
	
if (tval.eq.t(1)) yval = y(1)

  write (*, '(2f12.4)' ) tval+offset, yval
  write (10, '(2f12.4)' ) tval+offset, yval
    AEMIT(i) = yval
    TIME(i) = tval
  end do
close (10)



open(10, file='anemC.txt') 
write (10, '(2f12.4)') year, emissions
 EMIT(iyr) = initg


write (*, '(2f12.4)' ) TIME(iyr), EMIT(iyr)
    write (10, '(2f12.4)' ) TIME(iyr), EMIT(iyr)
 do i=iyr+1,fyr
  EMIT(i) = AEMIT(i) - AEMIT(i-1)

  write (*, '(2f12.4)' ) TIME(i), EMIT(i)
    write (10, '(2f12.4)' ) TIME(i), EMIT(i)
  end do
 
close (10)

end
 

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The immediate issue is that "cem()" is being used as an array but is not declared as such.
 
Thanks!

I have now found that my read statement is going to cause some trouble too!

Looks like I am reading in year and emissions each as a one dimensional array, and then trying to re-write them as a scalar entity.
 
uart said:
The immediate issue is that "cem()" is being used as an array but is not declared as such.

Thanks!

I have now found that my read statement is going to cause some trouble too!

Looks like I am reading in year and emissions each as a one dimensional array, and then trying to re-write them as a scalar entity?
 

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