Version 4.1.3 introduces `cudatoolkit` as dependency bloating install size by 860MB

[corneliusroemer]

Solution to issue cannot be found in the documentation.

• [X] I checked the documentation.

Issue

The SARS-CoV-2 tool Usher uses openmpi. When they upgraded openmpi from v4.1.2 to v4.1.3 it was noticed that suddenly cudatoolkit is required, which is very big at almost 900MB.

It appears that openmpi v4.1.3 started requiring ucx which in turn requires cudatoolkit.

Is this intentional? Is there a way to avoid the large dependency, or make it optional?

See this comment: https://github.com/cov-lineages/pangolin/issues/441#issuecomment-1117118349 and the enclosing for a discussion.

openmpi 4.1.2

"depends": [
    "libgcc-ng >=9.4.0",
    "libgfortran-ng",
    "libgfortran5 >=9.4.0",
    "libstdcxx-ng >=9.4.0",
    "libzlib >=1.2.11,<1.3.0a0",
    "mpi 1.0 openmpi",
    "zlib >=1.2.11,<1.3.0a0"
  ]

openmpi 4.1.3

 "depends": [
    "libgcc-ng >=10.3.0",
    "libgfortran-ng",
    "libgfortran5 >=10.3.0",
    "libstdcxx-ng >=10.3.0",
    "libzlib >=1.2.11,<1.3.0a0",
    "mpi 1.0 openmpi",
    "ucx >=1.12.1,<1.13.0a0",
    "zlib >=1.2.11,<1.3.0a0"
  ]

So openmpi 4.1.3 does in fact have ucx as a dependency, and ucx has cudatoolkit as a dependency:

"depends": [
    "__glibc >=2.17",
    "cudatoolkit >=11.2,<12",
    "libgcc-ng >=10.3.0",
    "libstdcxx-ng >=10.3.0"
  ],

[corneliusroemer]

Closing in favour of the much better written #102