Update install options

[rjleveque]

Add a warning about issues with pip install, and more details about
what this does.

I also added more description of the differences between PyClaw and
the Python modules used by Fortran versions to the pyclaw/index.rst page.

@ketch, @mandli: Please take a look at the diffs and the draft rendered pages at

• https://depts.washington.edu/clawpack/sampledocs/v580/installing.html
• https://depts.washington.edu/clawpack/sampledocs/v580/installing_pip.html
• https://depts.washington.edu/clawpack/sampledocs/v580/pyclaw/index.html

and let me know if these look ok.

I also removed the conda install discussion from the main pyclaw page, but it is still here:

• https://depts.washington.edu/clawpack/sampledocs/v580/installing_more_options.html#installing-conda

I assume this should be removed?

You might also take a look at

• https://depts.washington.edu/clawpack/sampledocs/v580/python.html#python

We still recommend Anaconda and Enthought. Should this be updated?

[rjleveque]

I also just updated the recommended pip install command with --use-deprecated=legacy-resolver as suggested in clawpack/clawpack#203.

[xyleme]

Hello Randall,
just in case it can help, I run clawpack on a debian 11 box and had the same install issue as #203 trying to upgrade from 5.7 to 5.8. Adding the --use-deprecated argument to pip instruction solved my problem.
Thanks for this!
Vincent.

[ketch]

Thanks for adding the new argument. I think that we should also suggest something like "if you only plan to use PyClaw and/or Visclaw", you may wish to simply do

pip install --user clawpack

since that avoids some of the issues you are referring to. I would include this in the "warning" on installing.html. Or we could just suggest the python-only and fortran-only installation methods first (not as a warning) with the "everything" installation line as a secondary option, since it is the problematic one. I think it's rather discouraging to start the installation instructions with a warning, and I believe there are very few people in the world who care about installing both parts.

[rjleveque]

@ketch, @mandli: Another attempt to simplify the instructions and clean up a number of related pages. Please see in particular these draft pages:

• https://depts.washington.edu/clawpack/sampledocs/v580/installing.html
• https://depts.washington.edu/clawpack/sampledocs/v580/installing_pip.html
• https://depts.washington.edu/clawpack/sampledocs/v580/installing_fortcodes.html
• https://depts.washington.edu/clawpack/sampledocs/v580/prereqs.html

[ketch]

The new version looks great to me. Thanks for doing this.