topic Re: Recursive function causes compile-time error in Intel® Fortran Compiler

Recursive function causes compile-time error

jfkfcia — Fri, 28 Feb 2003 05:11:38 GMT

Hi,

I have a simple recursive function that causes compilation with ifc to fail. It's as if recursion is not being allowed. The errors reported are:

      splinen = ( (x+n/2.)*splinen(x+0.5,n-1)
                           ^
Error 282 at (612:tfed.f) : This is not the name of a function but of a function result
     *     +(n/2.-x)*splinen(x-0.5,n-1))/(n-1)
                     ^
Error 282 at (613:tfed.f) : This is not the name of a function but of a function result

The code compiles fine with PGI and SGI MIPSPro compilers. Here is the function:

  RECURSIVE FUNCTION splinen(x,n)
  REAL x
  INTEGER n

  IF(n.eq.1) THEN
      IF(x.ge.-0.5 .and. x<0.5 ) THEN
          splinen = 1
      ELSE
          splinen = 0
      END IF
      RETURN
  ENDIF
  IF(abs(x)>n/2.) THEN
      splinen = 0
      RETURN
  ENDIF
  splinen = ( (x+n/2.)*splinen(x+0.5,n-1)
 F                    +(n/2.-x)*splinen(x-0.5,n-1))/(n-1)

  RETURN
  END

I don't see any relevant options in the manual, that I am not already using. I am compiling with the flags: -O2 -opt_report -WB -mp -openmp -fpp1 -auto -pc64 -c -cm -w95 -tpp7 -xW.

Thanks for any suggestions,
jfk.

Re: Recursive function causes compile-time error

sburger — Fri, 28 Feb 2003 23:59:49 GMT

You might try writing the function like this:

RECURSIVE FUNCTION splinen(x,n) RESULT(answer)
REAL x
INTEGER n,answer
IF(n.eq.1) THEN
IF(x.ge.-0.5 .and. x<0.5 ) THEN
answer = 1
ELSE
answer = 0
END IF
RETURN
ENDIF
IF(abs(x)>n/2.) THEN
answer = 0
RETURN
ENDIF
answer = ( (x+n/2.)*splinen(x+0.5,n-1)+(n/2.-x)*splinen(x-0.5,n-1))/(n-1)
END FUNCTION splinen

Re: Recursive function causes compile-time error

jfkfcia — Sat, 01 Mar 2003 07:03:39 GMT

Obviously I didn't look closely enough at the code to see that the problem was not the recursive call but the variable with the same name as the function :) So your suggestion of course fixed the problem. Many thanks.