Updates syngine client

[rmodrak]

Includes the following changes to how syngine Green's functions are cached locally

• adds new cache_path option to syngine.Client()
• if cache_path is not given, then attempts to download to MTUQ install directory (mtuq/data/greens_tensor/syngine/cache)
• if MTUQ install directory is not writeable, then attempts to download to current working directory (./syngine/cache)
• removes SYNGINE_CAHCE environment variable

[rmodrak]

Feel free to post any comments/reviews. Planning to merge on Tue Nov 19

[thurinj]

Hi @rmodrak,

Just wondering if removing the SYNGINE_CACHE variable is a good idea. I have the impression that it makes things easier when working on the containerized version of the code.
Not completely the greatest priority, as I suspect it is doomed to be deprecated at some times in the future, but using the syngine cache path variable was required to make my introduction to mtuq Google Colab notebook work.

[rmodrak]

Hi @thurinj, Good point, we could delay merging to allow for discussion during one of the monthly calls. Ultimately, there is a requirement to pass a particular code scan that may force a handful of changes like this. Sorry for the disruption.

[rmodrak]

In the meantime, it might be worth double checking the new implementation

• instead of an environment variable, it is now possible to specify the the Green's function cache path via an input argument to any of the syngine functions
• if the cache path is not specified or incorrectly specified, it attempts to fall back to a writeable directory

My hope is that with the above fallback, old notebooks would still continue to work

[thurinj]

Thanks for the explanation. If I can directly specify a path, I should be able to get pre-bundled syngine green's functions (I download a zip instead of waiting for the syngine fetching in my Google colab notebook) and then point to it.