Request for Intel oneAPI HPC Toolkit 2023.1 with Classic Fortran Compiler (offline installer)

[Tomotaka0613]

I am working with PLAXIS and need to compile a User-Defined Soil Model (UDSM), which requires the Intel® Fortran Compiler Classic (ifort.exe).

The latest versions of oneAPI no longer include the Classic Fortran Compiler, so I would like to request access to download the Intel oneAPI HPC Toolkit 2023.1 for Windows (offline installer), which includes ifort.

Could you please provide the download link for:
w_hpckit_offline_2023.1.0_xxxxx.exe

Thank you very much for your assistance.

[garraleta_fortran]

What is, exactly, the problem you have with ifx?

[Tomotaka0613]

Thank you for your reply.

The issue is that PLAXIS, the geotechnical finite element software I am using, only supports user-defined soil models (UDSM) compiled with the Intel® Fortran Compiler Classic (`ifort.exe`). It does not support `ifx`.

This requirement is clearly stated in the PLAXIS documentation, and attempts to compile with `ifx` result in errors or DLLs that cannot be loaded by PLAXIS.

Therefore, I need to use `ifort`, and for that reason, I am specifically looking for the offline installer of Intel oneAPI HPC Toolkit 2023.1 for Windows (`w_hpckit_offline_2023.1.0_xxxxx.exe`), which includes the Classic compiler.

Thank you very much for your understanding and support.

[garraleta_fortran]

In the manual (PLAXIS_2D_2024.2_2D_3_Material_Models.pdf) i have seen that you can use GNU fortran (!!IT'S FREE!!)

[Arjen_Markus]

Actually, so is ifx :).

[Tomotaka0613]

Thank you again for your response.

You're right — the PLAXIS material model manual mentions that some limited UDSM examples may be compiled with GNU Fortran.

However, for standard implementation of a user-defined soil model (UDSM), especially in recent versions like PLAXIS 2D 2024.2, PLAXIS explicitly requires the Intel® Fortran Compiler Classic (`ifort.exe`). This is confirmed both by the official documentation and by Bentley technical support.

PLAXIS does not recognize DLLs compiled with `ifx` or `gfortran` when trying to load them as user-defined material models.

That is why I need access to the oneAPI HPC Toolkit 2023.1 offline installer, which still includes `ifort`.

Thank you again for your support.

[Tomotaka0613]

Thank you again for your earlier comment.

After further testing, I wanted to correct what I previously said. It turns out that `ifx` — the modern Intel Fortran compiler — *can* be used to successfully compile a UDSM for PLAXIS 2D 2024.2, as long as all required subroutines (such as `plaxis_error`) are properly defined. The problem I encountered earlier was due to a missing symbol, not a compiler incompatibility.

I have not tried GNU Fortran yet, but your suggestion makes sense, and it's certainly worth exploring for those who want a fully free toolchain.

Thanks again for pointing me in the right direction. Your input was very helpful.

[Arjen_Markus]

Are you sure that you need the classic compiler? As far as I know the libraries built with ifx are compatible with ifort. I can imagine that the documentation for PLAXIS is lagging (it is almost impossible to keep documentation completely up-to-date).

My advice: try it and report here what is going wrong if anything does indeed go wrong. Something I can imagine: the runtime libraries are not automatically found, but that can be solved.

[Tomotaka0613]

Thank you for the suggestion and for your thoughtful reply.

Yes, I actually did try compiling the UDSM with `ifx` (the modern Intel Fortran compiler), and PLAXIS failed to recognize the resulting DLL — it did not load or list the user-defined material model at all.

Bentley Systems, the developers of PLAXIS, have confirmed that `ifort` (Intel Fortran Classic) is still required as of PLAXIS 2D version 2024.2. They explicitly state in the UDSM documentation that the DLL must be built with `ifort`.

I completely agree that documentation can lag behind, but in this case, the behavior appears to be consistent with what’s written.

So, yes — as of now, `ifort` remains necessary, and that’s why I’m looking for the oneAPI HPC Toolkit 2023.1 offline installer.

Thanks again for engaging constructively with this.

[Arjen_Markus]

If the DLL is not loaded, that could very well be because of runtime libraries that were not found. Extending the PATH environment variable would do the trick in that case. 

[Tomotaka0613]

Thank you for your earlier suggestion — I just followed your advice and compiled my model_softening_multi.f90 using ifx, and I'm happy to report that it worked!

The problem earlier was not due to incompatibility with ifx, but rather a missing definition for plaxis_error, which caused a linker error. Once I added a dummy definition of that subroutine, the compilation and linking completed successfully.

So yes, you're right — it seems that ifx can indeed be used to compile a UDSM for PLAXIS, at least for version 2024.2, provided the required interfaces and dummy routines are correctly handled.

Thanks again for pushing me to test it properly. This was very helpful!

[Arjen_Markus]

You're welcome - glad to be of help and glad to hear this is indeed working :).