CODEWITHSUNDEEP
fortrangfortran
user3531082
user3531082

Reputation: 13

Error compiling f77 intrinsics with gfortran

I am getting started with a HPC running Redhat 6.6. As a tutorial step for another program, I am asked to compile some old F77 code.

I am running the line gfortran 3bar.f I get the error message: 

/tmp/ccgUvoGd.o: In function `MAIN__':
3bar.f:(.text+0x43): undefined reference to `mygetarg_'
3bar.f:(.text+0x61): undefined reference to `mygetarg_'
3bar.f:(.text+0x8a): undefined reference to `mygetarg_'
collect2: ld returned 1 exit status

I believe this is related to the use of the sqrt intrinsic in the code. I have done some searching on this error and gfortran, but I get some squabbling about particular versions of Fortran for this and that.

I would really appreciate it if someone could advise me on how to get this code to work, as this is really not the point of what I am doing.

The code is: 

      program Three_bar

      implicit none
      real*8  a1,a2, g1,g2, weight, sum,
     1        l0,d0,sqrt
      intrinsic sqrt
      character*80 inp_fname, out_fname
      character*4  card1
      integer i, ir,iw, numb_args, iargc, numb_iter

      numb_args = iargc()
      if ( numb_args .ge. 2 ) then
         call MYGETARG(1,inp_fname)
         call MYGETARG(2,out_fname)
      else if ( numb_args .eq. 1 ) then
         call MYGETARG(1,inp_fname)
         out_fname = 'rdcs_output'
      else
         inp_fname = 'rdcs_input'
         out_fname = 'rdcs_output'
      endif

      ir = 7
      open (ir, file=inp_fname,status='UNKNOWN',access='SEQUENTIAL')

      iw = 8
      open (iw, file=out_fname,status='UNKNOWN',access='SEQUENTIAL')

      l0 = 1.0
      d0 = 1.0

c loop to spend some cpu - to test recall feature

      sum = 1.0

      numb_iter = 20000
      do 1005 i=1,numb_iter
         sum = (sum*1.00001)**1.001
         if ( sum .gt. 1.0e6 ) sum = 1.0
 1005  continue

c read the data from param file

      weight = (2.d0*sqrt(2.d0)*a1 + a2)*l0*d0
      g1=(2.d0*a1+sqrt(2.d0)*a2)/(2.d0*a1*(a1+sqrt(2.d0)*a2))-1.0d0
      g2 = 1.0d0/(a1 + sqrt(2.d0)*a2) -1.0d0
      write (iw,601) g1,g2,weight

      close (unit=ir,status='KEEP')
      close (unit=iw,status='KEEP')

 501   format(a4,1x,f30.0)
 601   format("g1 = ",e25.16," ",/,"g2 = ",e25.16," ",/,
     1       "weight = ",e25.16," ")

      stop
      end

Upvotes: 0

Views: 399

Answers (1)

Alexander Vogt
Alexander Vogt

Reputation: 18098

As noted in the comments, the compiler complains about a missing definition of MYGETARG, not SQRT.

The way you use that function reminds me of GETARG which is a GNU extension. My guess would by that MYGETARG is a wrapper function to make the code work with different compilers.

Since you are using gfortran, I would suggest to simply use GETARG instead. Then, your code compiles on my machine, albeit a few warnings.

On the long run, you should switch to something Standard conforming, such as GET_COMMAND_ARGUMENT.

Upvotes: 3

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