Delft3D FM build fails with ifx, need to install Intel Fortran Compiler Classic (ifort), unavailable

[InvertoEarth]

Hi,

I’m trying to build Delft3D FM (open-source release 2025.01) on Windows 10 (x64) using Visual Studio 2022 Community and Intel oneAPI 2025.2.
My CMake configuration completes successfully when using the new ifx compiler, but the build fails with multiple errors such as:

ifx: error #10298: problem during post processing of parallel object compilation

which seems related to OpenMP incompatibilities in ifx.

I therefore want to switch to the Intel Fortran Compiler Classic (ifort), which Delft3D FM is known to compile with.
However, I cannot find any option to install ifort in the Intel oneAPI 2025.2 installer GUI (both Base and HPC Toolkits).
Running ifort --version also shows it’s not available.

Could you please confirm:

1. Whether ifort is still distributed with oneAPI 2025.2 (or has been completely replaced by ifx),

2. If it’s still available, how to install it manually,

3. And whether there is any workaround to build legacy Fortran code (like Delft3D FM) that still requires ifort?

System details:

• OS: Windows 10 Pro 22H2 x64

• Visual Studio: 2022 Community 17.14.16

• Intel OneAPI: Base + HPC Toolkit 2025.2

• CMake: 3.29.6

• Project: Delft3D-FM open-source 2025.01 (ifx build fails with error #10298)

Thanks a lot in advance for your help!! That's very kind to take time to help people. 

Best, 

Olivier 

[Mentzer__Stuart]

The last oneAPI version with ifort was 2024.2. I don't believe it is available from Intel without a paid support license but some of us saved the 2024.2 offline installers and continue to use ifort alongside ifx.

Maybe someone else has experience with the ifx build error you are getting.

[Arjen_Markus]

I am surprised that the compilation fails - as one of the developers of Delft3D, I use Intel oneAPI 2025.0.0 and that gives no such problems. Can you provide more information about the build problems?

[Arjen_Markus]

It turns out that some of my colleagues ran into this problem as well. The solution is to use the 2025.0 version of the compiler. You do not need to jump through hoops to obtain the deprecate ifort compiler instead.

[InvertoEarth]

Thanks a lot for your answer !

But unfortunately, even the 2025.0 version isn't available anymore. That's a shame, but I would need a priority support that my startup cannot afford. 

I think I'll have to partially build Delft3D FM (D-flow FM only, hydrodynamic core with minimal parallel) with the ifx. Results will be less accurate but it's better than nothing. 

Thanks again ! 

Olivier from Inverto Earth 

[jimdempseyatthecove]

If you provide the error information, maybe someone here can give you a work around.

Jim Dempsey

[JohnNichols]

I tried the download and I got so lost.  Is there a simple set of instructions?