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 ❤️

[jwallwork23]

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.

[jwallwork23]

See #429