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Arturo Ortiz September 26, 2000 15:27

Fortran compiler
In order to compile UDS files in fluent 4.5 in W-NT the suggested (demanded)fortran compiler is absoft's. I do not have it and I can`t afford it. I have Compaq's compiler and g77 (free). Is there a way to use other compilers or are we cursed to use absoft's?


John C. Chien September 26, 2000 22:02

Re: Fortran compiler
(1). It wouldn't be difficult to e-mail the Fortran source code to Fluent's support engineer for compilation. (2). That's only my personal idea. Why not give it a try?

Greg Perkins September 29, 2000 02:37

Re: Fortran compiler
I think John's idea is not bad - but I find I need to recompile fairly regularly when developing complex code - other people may be more perfect I suppose.

According to Fluent you can use a compiler which produces compatible object binaries as the Absoft one - which just happens to be fairly expensive.

I thought about testing g77 but then decided for me it really wasn't worth it - since none of our PCs are big/fast enough for my problem anyway.

Like many things - the answer is - if it works, it works and if it doesn't it doesn't. If you get it to work - please let me know.


John C. Chien September 29, 2000 11:39

Re: Fortran compiler
(1). Can you borrow an old version of the compiler from friend? or from the support engineers? (2). I mean if you are really doing the important thing, there is always a way out. (just ask the support engineer to lend a copy of an old version of the compiler. It shouldn't be that difficult. You can return it when you are done with your project.) There must be a lot of old versions out there.

Arturo Ortiz September 29, 2000 20:32

Re: Fortran compiler
As Greg has pointed, Absoft's compiler is quite expensive. I've tried Visual fortran and g77 but fluent refuses to use them even if in the makefile there exists a DVF choice (Digital Visual Fortran)and I have set it active. Absoft's fortran is not used here and I do not know nobody who uses it. I've tried desesperately to get an old version as Jhon says, but I have not had success. Fluent's people told me that absoft's is a must, and their way to handle their bussiness is very restricted so I don't think they will lend me a compiler. I'm still in the search, if somebody has something I will appreciate it very.

John C. Chien September 29, 2000 21:03

Re: Fortran compiler
(1). Take a look at the absoft website,

(2). There is a statement by the Assistant Dean for Engineering Computing at the Virginia Tech., that all 1400 freshmen engineering students are required to own absoft c, C++, and Fortran compilers. (under Academic Price List of absoft home page..)

(3). You can post your need at their website (the engineering school). good luck.

andy October 2, 2000 08:34

Re: Fortran compiler
A possible work around may be to tell Fluent you are using C (which it seems to like more) and to place a C wrapper around your Fortran subroutine. Calling Fortran from C is relatively straightforward if you follow the calling conventions adopted by your C/Fortran combination. These vary a bit from system to system in things like placement of underscores and handling the length of strings. The gcc and g77 info pages give details.

Please post back if it is successful.

Greg Perkins October 2, 2000 17:57

Re: Fortran compiler
While I haven't compiled any Fluent v4.5 user code under Windows, I have linked my C code to the Fluent Fortran templates for v4.5 using the wrappers you've mentioned. I have done it using f77 and cc under HP-UX (easy) and SGI Irix (painful).

HP-UX provides a nice compiler directive to pass Fortran parameters to C as either value or by reference type. Unfortunately, under SGI Irix I needed to use wrappers generated in the make process. This took a while to get working.

Regards Greg

Arturo Ortiz October 3, 2000 13:57

Re: Fortran compiler
Finally I've been successful in compiling with Digital Visual Fortran, the only trick is to use version 5 and the compilation get well. Not everything is Ok, when the Linking stage begins it sends me the following message:

Fatal error in Pass2

I dont think is because of the fortran compiler but of another source, but I don have a clue about how to fix it.


Greg Perkins October 3, 2000 22:41

Re: Fortran compiler
While I don't know the details of what your doing, I assume you've been able to compile 'your' user code. The next step is to link it to the object files supplied by Fluent.

As I mentioned in a previous post - you will need to ensure that any compiler/linker you use, is compatible with the object codes produced by the Absoft one Fluent has used in generating the pre-compiled objects.

I don't know whether there are standards on object files or not. You probably should check. If they're aren't and every compiler uses a different standard its very unlikely you can use a compiler other Absoft Fortran.

From your comments I suspect this may be the problem. Of course, your problem may be something different altogether....

Arturo Ortiz October 4, 2000 10:54

Re: Fortran compiler
Hi Greg I compiled all the fluent libraries and finally I got an exe file called fl415.exe, but then the compiler stoped giving me the fatal error in pass 1.

Anyway I think you're right and we are doomed to follow fluent's directions and use absoft's compiler.

Thanks everybody for your help. Arturo

Arturo Ortiz October 4, 2000 13:36

To andy
I will try your approach and re-post if I can do it, thanks for the idea. Regards

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