Support cuTENSOR in pathfinder

[leofang]

Both nvmath-python (cc @yangcal) and CuPy will need it.

New functionality needed:

load_nvidia_dynamic_lib("cutensor")
load_nvidia_dynamic_lib("cutensorMg")
find_nvidia_header_directory("cutensor")

[yangcal]

Is it gonna be inside the bindings? Should cuquantum C libs be supported too?

[leofang]

Most of nvmath modules have switched over to use pathfinder (which helps avoid the RPATH hack at build time), so I assume it's good to help them stay consistent.

For cuQuantum Python, I guess it is really up to you if you want to replace the existing code in the codegen with pathfinder 🙂 I think the search behavior should be compatible and technically there is no strong reason for changing.

[ZzEeKkAa]

Tarballs (https://developer.nvidia.com/cutensor-downloads?target_os=Linux&target_arch=x86_64&Distribution=Agnostic):

• wget https://developer.download.nvidia.com/compute/cutensor/redist/libcutensor/linux-x86_64/libcutensor-linux-x86_64-2.3.1.0_cuda13-archive.tar.xz
• wget https://developer.download.nvidia.com/compute/cutensor/redist/libcutensor/linux-x86_64/libcutensor-linux-x86_64-2.3.1.0_cuda12-archive.tar.xz

Wheels:

• https://pypi.org/project/cutensor-cu12
• https://pypi.org/project/cutensor-cu13

Conda:

• https://anaconda.org/conda-forge/cutensor

[rwgk]

Quick triaging:

pip install cutensor-cu13
pip install cutensor-cu12

::::::::::::::
./cutensor_cu12-2.3.1.dist-info/RECORD
::::::::::::::
cutensor/include/cutensor.h
cutensor/include/cutensor/types.h
cutensor/include/cutensorMg.h
cutensor/lib/libcutensor.so.2
cutensor/lib/libcutensorMg.so.2

::::::::::::::
./cutensor_cu13-2.3.1.dist-info/RECORD
::::::::::::::
cutensor/include/cutensor.h
cutensor/include/cutensor/types.h
cutensor/include/cutensorMg.h
cutensor/lib/libcutensor.so.2
cutensor/lib/libcutensorMg.so.2

[rwgk]

@ZzEeKkAa Where are the tarballs usually installed? Do we need to support certain standard locations?

[rwgk]

From off-line discussion:

When using tarballs, users are expected to set LD_LIBRARY_PATH, or install into a directory that is already covered by ldconfig (such as /usr/lib).

This means libcutensor will be found by the system search and we don't need any special code in pathfinder.