Fortran error, use '-fcoarray=' to enable

Question

I'm having some troubles with an awkward error in fortran, this is the code I need in order to get simulation of materials in solid state

  PROGRAM EUCLID
    PRINT *, 'A?'
    READ *, NA
    IF (NA.LE.0) THEN
      PRINT *, 'A must be a positive integer.'
      STOP
    END IF
    PRINT *, 'B?'
    READ *, NB
    IF (NB.LE.0) THEN
      PRINT *, 'B must be a positive integer.'
      STOP
    END IF
    PRINT *, 'The GCD of', NA, ' and', NB, ' is', NGCD(NA, NB), '.'
    STOP
  END

  FUNCTION NGCD(NA, NB)
    IA = NA
    IB = NB
1   IF (IB.NE.0) THEN
      ITEMP = IA
      IA = IB
      IB = MOD(ITEMP, IB)
      GOTO 1
    END IF
    NGCD = IA
    RETURN
  END

The error says Coarrays disabled at (1), use '-fcoarray=' to enable|, but I'm not using any arrays, so what should I do?

I'm using codeblocks as my compiler, and had no issues with some previous programs I wrote

Are you sure you don't have any coarray or are trying to wrongly declare an array with square brackets (like this: `integer :: arr[,]`) in any part of your code and included/linked files? Could you point us which line of code the error is referring to? — Rodrigo Rodrigues, Sep 04 '18 at 19:34
Please provide more details about the underlying compiler used. Also, perhaps you could try removing the `call init_random_seed` part. — francescalus, Sep 04 '18 at 19:38
Alternatively, of course, try adding an appropriate `-fcoarray=` flag to the compile options. Again, we'll need details of your compiler to be able to suggest an appropriate value. — francescalus, Sep 04 '18 at 19:44
Consider changing `init_random_seed` to the intrinsic `random_seed` procedure. — Rodrigo Rodrigues, Sep 04 '18 at 19:45
this is the subrutine I'm using https://pastebin.com/DtX6nGvV — codemonkey00016, Sep 04 '18 at 19:46
@francescalus how to add that flag to my codeblocks compiler? — codemonkey00016, Sep 04 '18 at 19:47
See [this other question](https://stackoverflow.com/q/33208733/3157076). — francescalus, Sep 04 '18 at 19:56
As the subroutine you link to is probably very relevant please copy it directly into your question. — francescalus, Sep 04 '18 at 19:57
fixed it by removing the init_random_seed, thanks a lot guys — codemonkey00016, Sep 04 '18 at 20:06

Rodrigo Rodrigues · Accepted Answer · 2018-09-04T20:15:38.587

If you are not planning to use coarrays and don't bother with threads and images, just abandon this custom init_random_seed subroutine and substitute it with the intrinsic random_seed subroutine. From the function reference here:

If RANDOM_SEED is called without arguments, it is seeded with random data retrieved from the operating system.

Else, if you do plan to use coarray features and do bother with threads and images (only recommended for advanced usage) you can use the new intrinsic random_init, if it is avaliable in your compiler. If it is not, then it is advisable to use a library, like OpenCoarrays, or implement it by your own.

Please use the GFortran documentation matching the version of the compiler used. For that PRNG, in particular, there were large changes in gcc 7. — janneb, Sep 05 '18 at 09:44

score 0 · Answer 2 · answered Sep 04 '18 at 20:07

0

init_random_seed I was using was implemented the wrong way, so I removed it completely and edited the code

answered Sep 04 '18 at 20:07

codemonkey00016

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Fortran error, use '-fcoarray=' to enable

2 Answers2