Learning Forum

[nsummerlin]

I am a University of Florida student working with Michael Omana and Adam Hammond-Clements from Sandia National Labs on a project that uses the user-defined collision kernel functionality of Ansys Chemkin.

 

Software installed: Ansys Chemkin 2024 R2, Intel Fortran Classic Compiler 2024.0.2

 

Following the Ansys API Manual, we edited the user_routines.f90 file (...chemkin.win64/user_routines/user_routines.f90), compiling it via the makefile in the same directory (...chemkin.win64/user_routines/user_routines_pc.mak) into user_routines.lib (...chemkin.win64/lib/user_routines.lib).

 

(It should be noted that before each step, as appropriate, the FLEXLM_ARCH environmental variable was appropriately set for Windows)

 

Proceeding with the linkage step, we renamed the bin files associated with the modified "Get Custom Collision Kernel" subroutine, also outlined in the API manual (...chemkin.win64/bin/auroradll.dll, ...chemkin.win64/bin/auroradll.exe, ...chemkin.win64/bin/auroradll.lib) and ran the appropriate makefile to rebuild auroradll.dll linked with user_routines.lib (...chemkin.win64/drivers_cpp/drivers_cpp_pc.mak), using the following command (from the API manual):

 

nmake -i -f drivers_cpp_pc.mak ..\bin\auroradll.dll

 

But this command, when executed in a oneAPI command prompt with Administrator Permission, returns the error message:

 

NMAKE : fatal error U1073: don't know how to make '..bin/auroradll.dll'

 

Any help with properly running this makefile to link the shared-object libary would be greatly appreciated, as this is a near-total roadblock to our research until we can resolve it.

[jcooper]

Hi:

There are quite a few possible reasons for this error:

1. Compiler compatibility: Your compiler seems to be somewhat newer than the supported versions shown in our compiler requirements guide. The compile and link flags and system libraries used in the make files have been verified with the supported compilers and corresponding platforms:

Microsoft Visual Studio Professional 2022 Version 17.6.x (including the MS C++ compiler),

Intel OneAPI 2023.1.0 Classic C++ compiler (version 2021.9.0) and

Intel OneAPI 2023.1.0 Classic FORTRAN compiler (version 2021.9.0) (for Chemkin API, Chemkin user-programmed subroutines and FORTE output user routines.)

This is documented in the API manual here: https://ansyshelp.ansys.com/Views/Secured/corp/v252/en/chemkin_api/i43132.html

 

2. Linker failure: Is aurora.dll at the expected location? If the linking stage failed, then the problem may be that the .dll file is absent.

 

I would suggest first trying the little sample program we have for testing your compilers. It is located in the utilities folder of the Chemkin installation.

1. Open the test program to compile and link, named helloTest_Intel_Composer.zip. 

2. Copy this .zip file to a Windows system and extract it to create a helloTest sub-directory.

3. For the Linux platform, copy the helloTest sub-directory to your Linux system.

4. Set up your compiler environment.

5. Follow the directions in the readme.txt file to use the make utility to compile and link the test programs. The test programs should compile and run as described in the readme.txt file.  

I hope this helps to sort out the problem.

[nsummerlin]

Hello!

1. The installed compiler is a version of the Intel Fortran Compiler Classic which is slightly newer than recommended, but shares the "ifort" syntax. Is the C++ compiler additionally necessary for linking this user-defined function, even though it's only written and compiled in Fortran?
2. The file "auroradll.dll" is not supposed to be at the expected location, according to the API manual. It's supposed to not be found by the makefile (the API manual suggests either moving or renaming it to keep a backup of the installed auroradll.dll), and the makefile is supposed to recreate it with the compiled user-defined function linked in.

Any additional assistance you could offer would be much appreciated.

[jcooper]

Hi! 

I am not really an expert on compilers, but I would recommend going back to basics in order to troubleshoot this, possibly getting IT involved. 

If the "hello world" program doesn't compile, then there is a configuration issue of some kind that will prevent anything from compiling until it is addressed.

[nsummerlin]

Hello! The "hello world" function compiled fine for Fortran, but not C++, because I don't have a C++ compiler. The only IT I can get any sort of useful answer from is y'all, because we don't have the permissions to open an Ansys Case for Technical Support. If you could just let me know if I need the C++ Compiler to link the collision kernel, that would be enough to help.

[easywaystorage5]

Yes — for Chemkin’s user-defined collision kernel linkage, you almost certainly do need the C++ compiler as well as Fortran, even though your custom routine is written purely in Fortran.

The reason:

• auroradll.dll is not just a Fortran library — it’s a mixed-language build where Ansys provides core functionality in C++ and expects to link in your compiled Fortran object(s).

• The makefile drivers_cpp_pc.mak is written for the C++ toolchain (MSVC + Intel integration). It uses the C++ linker to combine the existing Chemkin binaries with your user_routines.lib.

• Without the MSVC C++ compiler, nmake will fail because it can’t process .cpp object dependencies or use the correct Windows linker flags that Ansys sets for auroradll.dll.

What this means for you

• Install Microsoft Visual Studio Professional 2022 (or Community Edition if license allows) with the Desktop development with C++ workload.

• Make sure it’s a version compatible with Intel OneAPI Classic compilers — Ansys supports VS 2022 17.6.x paired with Intel OneAPI 2023.1.0 (Fortran + C++).

• Once installed, open an Intel oneAPI + MSVC developer command prompt, set FLEXLM_ARCH as before, and rerun:

  bash

  CopyEdit

  nmake -i -f drivers_cpp_pc.mak ..\bin\auroradll.dll

• That should allow the makefile to correctly compile any C++ stubs and link your Fortran routine into the rebuilt auroradll.dll.

If you try this without MSVC installed, nmake will keep failing because it doesn’t know how to build the intermediate C++ targets that are part of the DLL build chain.