Path: utzoo!attcan!uunet!yale!cmcl2!lanl!jlg
From: jlg@lanl.gov (Jim Giles)
Newsgroups: comp.lang.fortran
Subject: Re: IDENTIFY statement in Fortran 8x
Message-ID: <8081@lanl.gov>
Date: 17 Jan 89 23:11:32 GMT
References: <4462@pitt.UUCP>
Organization: Los Alamos National Laboratory
Lines: 26

From article <4462@pitt.UUCP>, by whit@pitt.UUCP (Debbie Whitfield):
>        IDENTIFY /1:M/ D(I) = C(I,I+1)
> 
> which is a pseudonym for the diagonal of an array. I am curious about
> what is considered as a valid expression for describing elements of C.  
> Can any expression be used?  What about function calls?

The actual syntax of IDENTIFY was as follows:

      IDENTIFY (DIAG(I)=ARRAY(I,I), I=1:N)  !8X standard 6.2.6.2

The allowed subscript expressions for ARRAY must be linear in I.  A
multi-dimensional IDENTIFY is also possible:

      IDENTIFY (X(I,J) = A(3*I+5,J+I,4,2*J), I=1:N, J=1:M)

Each subscript expression must be linear and the subscript names must
appear, at most, once in each subscript expression.  Note that the subscript
expressions need not contain the subscript names from the 'parent' array
at all (like the constant '4' in the example).  Note also that the prohi-
bition against non-linear expressions also prohibits function calls.

The question is moot however, since the latest standard has eliminated
IDENTIFY.

J. Giles