Include fpm build support

[jalvesz]

Hi, I just wanted to propose (and ask if there is interest on the maintainers side) to include support for building the project using fpm https://fpm.fortran-lang.org/

(I'm currently using your project that I build with CMake with a few tweaks but also like a lot the fpm workflow :) )

If so, I started playing with an fpm.toml at the root of the project (WARNING It doesn't work for the moment):

name = "FTorch"
version = "0.1.0"
license = "license"
author = "ICCS"
maintainer = "ICCS"
copyright = "Copyright 2019, Institute of Computing for Climate Science"

[library]
include-dir = ["<paht_to_libtorch>/libtorch/include","<paht_to_libtorch>/libtorch/include/torch","<paht_to_libtorch>/libtorch/include/c10/util","<paht>/libtorch-lin-shared-with-deps-2.1.1+cpu/libtorch/lib"]

[build]
auto-executables = true
auto-tests = true
auto-examples = true
module-naming = false

external-modules = ["torch", "torch_cpu", "c10"]
link = ["torch", "torch_cpu", "c10"]

[install]
library = false

[fortran]
implicit-typing = false
implicit-external = false
source-form = "free"

and this would need a command line such as:

export TORCH_INC="<paht_to_libtorch>/libtorch/include"
export TORCH_LIB="<paht_to_libtorch>/libtorch/lib"
fpm build --flag "-cpp -std=c++17 -I$TORCH_INC -L$TORCH_LIB"

For the moment I'm hitting an error with this approach:

././src/ctorch.cpp:2:10: fatal error: torch/torch.h: No such file or directory
    2 | #include <torch/torch.h>

Not sure yet why

[jatkinson1000]

Absolutely, and if you are able to implement this please feel free to open an issue, add it as a feature request, and assign yourself.

Once you have something ready open a PR and we'll review and get it merged.

Thanks for using the project and wanting to contribute ❤️

[joewallwork]

Having a go at setting this up while I'm at an fpm session with @everythingfunctional. I get some progress with

fpm build --cxx-flag "-cpp -std=c++17 -I${Torch_DIR}/include -I${Torch_DIR}/include/torch/csrc/api/include -L${Torch_DIR}/lib" --verbose

Working on this on branch 77_fpm.

Next need to look into missing preprocessor flags.

[jatkinson1000]

Super, @niccolozanotti was asking about this at the meeting this morning, so ccing here so everyone is aware of any progress.

[joewallwork]

See #429

[joewallwork]

I made some progress with setting up fpm for FTorch in #429. However, we decided to shelf this effort for now for the following reasons:

• Whilst I was able to build FTorch itself using fpm, I wasn't able to build the examples. I raised support request fpm:#1226 but haven't heard back yet.
• Another issue is that fpm is incompatible with pFUnit - our current unit testing framework (see pFUnit:#499).
  • Alternative Fortran unit testing frameworks include test-drive (see #482) and veggies (see #484). I had a go at setting these up and found that test-drive was easy to set up but lacking in functionality (it doesn’t support parametrisation) and development activity. Veggies, on the other hand, appears to be actively developed and with mature functionality, but difficult to set up in a project that's not already using fpm (leading to a chicken-and-egg situation).

Given the development effort and uncertainty associated with switching unit testing frameworks, we do not plan to move any further with setting up fpm for now.