CODEWITHSUNDEEP
fortranmingw
Alcaeos
Alcaeos

Reputation: 13

Syntax Error/Two main programs Fortran

I'm trying to compile this program for monte carlo importance sampling, but i'm running into a couple issues:

1 - Error: Syntax error in data declaration at (1), referring to the following line, where the (1) is placed right after and beneath the word "function".

real function f(x)

2 - Error: Two main PROGRAMS at (1) and (2), referring to these two lines

program importance1

and 

t=0.0

.

The sample code follows. There are more lines of code in the program, but I don't think there are any problems so I've just posted this first segment.

program importance1
implicit none
real mean_value,t,ta,rr
real x,xtrials,s_square_old,s_square_new,std_dev,std_error,frac_stand_dev
integer k
real :: alpha=0.90
integer :: trials=50
xtrials=trials

real function f(x)
f=exp(x)
return
end

real function g(x)
g=(alpha/(exp(alpha)-1.))*exp(alpha*x)
return
end

t=0.0
s_square_old=0.0

Upvotes: 1

Views: 772

Answers (1)

Kyle Kanos
Kyle Kanos

Reputation: 3264

Not sure where you got the idea to do that, but it looks like you are defining functions in the middle of your code, which is the wrong place. In Fortran, the functions go in a separate MODULE or at the end of the program under a CONTAINS block:

program importance1
  implicit none
  real :: mean_value,t,ta,rr
  real :: x,xtrials,s_square_old,s_square_new,std_dev,std_error,frac_stand_dev
  integer :: k
  real :: alpha=0.90
  integer :: trials=50
  xtrials=trials

  t=0.0
  s_square_old=0.0

contains

  real function f(x)
    real :: x
    f=exp(x)
  end function

  real function g(x)
    real :: x
    g=(alpha/(exp(alpha)-1.))*exp(alpha*x)
  end function

end program

Upvotes: 1

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