forums.silverfrost.com

simon · Joined: 05 Jul 2006 Posts: 270

I would have expected the following program to print 0 and 2, but FTN95 and at least two other compilers return 1 and 3. The program is trying to print the lower bound of an array within a derived type, when the lower bound is explicitly defined as 0. Please advise how my understanding is incorrect.

mecej4 · Joined: 31 Oct 2006 Posts: 1897

You may find the answer if you replace (0:2) by (-2:0) in the definition of t%i and see how that changes the results.

Changing the Print statement to

simon · Joined: 05 Jul 2006 Posts: 270

Thanks for the response. Indeed, the same output. The lower bound becomes 1 regardless of the definition. So effectively, you cannot use different bounds in a derived-type array?

PaulLaidler · Posted: Wed Feb 01, 2023 7:45 am Post subject:

Use the whole array...

simon · Joined: 05 Jul 2006 Posts: 270

Hmm, that is curious. What actually is the difference between at(1)%i and at(1)%(:), or, for that matter, between, say, iarray and iarray(:)?

PaulLaidler · Posted: Wed Feb 01, 2023 3:59 pm Post subject:

The colon usually denotes an array section, a sub-array which is a copy of part of the whole. Presumably the copy can be of the whole but is a different object with, in this context, different properties.

simon · Joined: 05 Jul 2006 Posts: 270

I think I get that. But what about the following? Surely this code should return 2 rather than 3. And it returns 3 even if you delete (:) in the Print statement

PaulLaidler · Posted: Mon Feb 06, 2023 9:15 am Post subject:

Simon

It looks like FTN95 is giving an incorrect result in this context. I will log this for investigation.

simon · Joined: 05 Jul 2006 Posts: 270

Hi Paul,
Any progress on this one? I have work-arounds, but I have quite a few instances that I think are equivalent, where I am passing an array of a derived type, and the routine does not get what I would expect. For example,

PaulLaidler · Posted: Wed Nov 08, 2023 9:02 am Post subject:

Simon

This failure has not yet been fixed. An initial investigation located the point of failure but not the fix.

At first sight it's not obvious to me what you are asking for in the call to s(at2(:)%t%i(1)), which is some kind of "copy-in" of components extracted from the data structure.

Sometimes it is better to simplify the logic of the coding.

PaulLaidler · Posted: Wed Nov 08, 2023 3:09 pm Post subject:

Simon

If Call s(at2(:)%t%i(1)) does not do what you expect then can you provide sample code that illustrates what you get and what you expect.

It could easily be a different issue.

simon · Joined: 05 Jul 2006 Posts: 270

Hi Paul,
The following example does not quite reproduce the error I have in mind, but it is outputting a surplus value (which is presumably because the size of ia in subroutine s is still in error):

PaulLaidler · Posted: Thu Nov 09, 2023 8:33 am Post subject:

Simon

Thanks. I have logged this for investigation.

PaulLaidler · Posted: Thu Nov 23, 2023 3:40 pm Post subject:

This failure has now been fixed for the next release of FTN95.