Add conan files

[codingwithmagga]

Conan

Add conan files to create a matx conan package.

Workflow

In the main folder run

conan create .

This creates the matx conan package on your system.

Test

After creating the conan package create a new folder with a conanfile.py.

import os

from conan import ConanFile
from conan.tools.build import can_run
from conan.tools.cmake import CMake, CMakeToolchain, cmake_layout

class TestPackageConan(ConanFile):
    settings = "os", "compiler", "build_type", "arch"
    generators = "CMakeDeps", "VirtualRunEnv"
    test_type = "explicit"

    def requirements(self):
        self.requires('matx/1.0.0')

    def layout(self):
        cmake_layout(self)

    def generate(self):
        tc = CMakeToolchain(self)
        tc.generate()

    def build(self):
        cmake = CMake(self)
        cmake.configure()
        cmake.build()        

    def test(self):
        if can_run(self):
            bin_path = os.path.join(self.cpp.build.bindirs[0], "test_package")
            self.run(bin_path, env="conanrun")

I added a CMakeLists.txt and a folder src where I copied the examples from this repo to.

cmake_minimum_required(VERSION 3.25.2)

if(NOT DEFINED CMAKE_CUDA_ARCHITECTURES)
    set(CMAKE_CUDA_ARCHITECTURES "native")
    message(STATUS "Using native GPU architecture since CMAKE_CUDA_ARCHITECTURES not defined")
endif()

project(test_package LANGUAGES CXX CUDA)

find_package(matx CONFIG REQUIRED)

add_subdirectory(src)

Now you can run conan build . to create the examples using conan and the matx conan package.

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[cliffburdick]

Thanks for doing this! One comment I have is that the version number is hard-coded in many places making it a maintenance burden to update all the right places. Would it be possible to grab the source version from CMakeLists.txt, which is our current source of truth? Also, what would be required to make this present in the public conan repo?

[greptile-apps]

Greptile Summary

This PR adds Conan 2 packaging support for MatX, introducing a root-level conanfile.py recipe, a test_package/ directory with a consumer test recipe and a CUDA smoke test, and corresponding documentation updates in README.md and docs_input/build.rst.

• conanfile.py: Declares package_type = \"header-library\", exports sources, configures and installs via CMake, and exposes the installed cmake config directory through cpp_info.builddirs. Missing no_copy_source = True, which causes Conan to unnecessarily copy the large source tree (including cmake/rapids-cmake/) to the build folder. Additionally, cmake.configure() internally triggers CPM/FetchContent to download CCCL from GitHub, so conan create . silently requires internet access without declaring CCCL as a Conan dependency.
• test_package/: Correctly uses self.tested_reference_str for the requirement, uses CMakeDeps + CMakeToolchain for dependency resolution, and builds a minimal CUDA executable to verify the package works end-to-end.

Confidence Score: 4/5

Safe to merge as a first-cut Conan packaging addition; no changes to library code or existing build infrastructure.

The core recipe logic is sound and follows Conan 2 conventions. The main gap is that conan create . silently downloads CCCL via CPM without declaring it as a Conan dependency, which breaks in offline environments. Missing no_copy_source = True causes unnecessary large file copies on every packaging run. Neither issue prevents the package from working in a standard online developer environment, but both are worth fixing before this recipe is widely distributed.

conanfile.py — the recipe's missing no_copy_source and undeclared CPM-based CCCL download are the items that warrant a follow-up look.

Important Files Changed

Filename	Overview
conanfile.py	New Conan 2 recipe for the matx header-only library; correctly uses package_type = "header-library" and installs via cmake, but is missing no_copy_source = True and implicitly depends on internet access during packaging (CCCL fetched via CPM)
test_package/conanfile.py	Standard Conan 2 test package recipe; correctly uses self.tested_reference_str instead of hardcoding the version, missing trailing newline
test_package/test_package.cu	Minimal CUDA smoke test that creates a tensor and prints it; has an unused using namespace matx declaration alongside explicit matx:: qualifiers, and is missing a trailing newline
test_package/CMakeLists.txt	Clean CMake configuration for the test package; correctly uses find_package(matx CONFIG REQUIRED) and links against matx::matx
README.md	Adds documentation for the new Conan workflow under a numbered section; content is accurate and consistent with the recipe
docs_input/build.rst	RST documentation for Conan support added cleanly with correct code-block directives and accurate workflow description
.gitignore	Adds CMakeUserPresets.json to gitignore (generated by some CMake/IDE workflows)

Sequence Diagram

sequenceDiagram
    participant Dev as Developer
    participant Conan as Conan CLI
    participant CMake as CMake
    participant CPM as CPM/FetchContent
    participant GitHub as GitHub (CCCL)
    participant Cache as Local Conan Cache

    Dev->>Conan: conan create .
    Conan->>CMake: cmake.configure()
    CMake->>CPM: rapids_cpm_cccl()
    CPM->>GitHub: Download CCCL (requires internet)
    GitHub-->>CPM: CCCL source
    CMake-->>Conan: Configure done
    Conan->>CMake: cmake.install()
    CMake-->>Conan: Headers + cmake config files
    Conan->>Cache: Store matx/1.0.0 package

    Dev->>Conan: conan build . (test_package)
    Conan->>CMake: Generate CMakeDeps + CMakeToolchain
    CMake->>Cache: find_package(matx CONFIG REQUIRED)
    Cache-->>CMake: matx::matx target
    CMake-->>Dev: test_package binary built

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_{Reviews (1): Last reviewed commit: "Merge branch 'codingwithmagga/fix-359-pa..." | Re-trigger Greptile}

[codingwithmagga]

Thanks for doing this! One comment I have is that the version number is hard-coded in many places making it a maintenance burden to update all the right places. Would it be possible to grab the source version from CMakeLists.txt, which is our current source of truth? Also, what would be required to make this present in the public conan repo?

@cliffburdick
Glad to help you :)

I start with the second question:
So in general we need to create an issue and pull request (including signing an NDA) in the conan center recipes repo. We need to add the conanfile.py and the files from the test_package folder as well as two other files: config.yml and conandata.yml.

conandata.yml may look like this:

sources:
  "1.0.0":
    url: "https://github.com/NVIDIA/MatX/archive/refs/tags/v1.0.0.tar.gz"
    sha256: "some_sha"

And config.yml like this:

versions:
  "1.0.0":
    folder: all

I never uploaded an open source conan package to this repository so it may be that they have some small change requests, but I assume that the changes won't be to big. But this process may take some time.

If you want I can have a look at this next week or you can do that by yourself of course.

To your first question:

Although it is in principle possible to get the cmake version into your conan file I would not recommend that since conan calls cmake not the other way around.
The problem will also more or less disappear when uploading the files to the conan center since we can then access the two yml-files mentioned above and get the version information from there. This is just a small change in the conanfile.py
If you create a new MatX version in this repo, you (or any other person) just need to update the two yml files in the conan center repo to make the new MatX version, e.g. 1.1.0, available for all conan users.

I updated the documentation slightly to a generic MatX version to remove the hardcoded 1.0.0 version there.