topic Q re purtting variables in Format statements in Intel® Fortran Compiler

Q re purtting variables in Format statements

WSinc — Tue, 19 Jun 2012 16:53:34 GMT

Suppose I have a stiuation like this:

integer q(1:20),nq,nx
realx(1:20)
print 101,x(1:nx), q(1:nq)
101 format("x=",4F20.12," q=",4I10)

This works fine as long as nx=4, and nq is <= 4.
But if those values change, I want the FORMAT statement to reflect that.

The way I now handle that is to modify the FORMAT statment at execution time by
putting it in a CHARACTER array.

Has Fortran come up with a cleaner way to do this? I couldn't find anything.

Q re purtting variables in Format statements

Steven_L_Intel1 — Tue, 19 Jun 2012 19:34:23 GMT

The Fortran standard doesn't have a cleaner way of doing what you want. In some circumstances, the Fortran 2008 "unlimited group repeat count" feature can help, but not here.

Intel Fortran supports an old extension that does what you want, called Variable Format Expressions. The syntax would be:

101 format("x=".F20.12,"q=",I10)

This extension is widely implemented, but not universally so.

Q re purtting variables in Format statements

WSinc — Tue, 19 Jun 2012 19:51:56 GMT

Ok, I will try that. Thanks ! !

Q re purtting variables in Format statements

Steven_L_Intel1 — Tue, 19 Jun 2012 20:35:12 GMT

No - what goes inside the <> is just an ordinary expression.

Q re purtting variables in Format statements

IanH — Tue, 19 Jun 2012 21:18:36 GMT

For your specific example you could do something like the following, without having to resort to extensions:

[bash] WRITE (*, "('x=',*F20.12)", ADVANCE='NO') x(:nq) WRITE (*, "(' q=',*I10)") q(:nq)[/bash]

Q re purtting variables in Format statements

Steven_L_Intel1 — Wed, 20 Jun 2012 00:36:36 GMT

Dang - I should have thought of that! Thanks, Ian!