Linear Code's covering_radius method forces the use of optional package Guava

[sagetrac-dlucas]

The method covering_radius for linear codes (in linear_code.py), uses optional package Guava for Gap by default.

If this package is not installed, the method crashes without a proper error message.

This ticket proposes a reimplementation of covering_radius, with a generic algorithm written in Python. If Guava is not installed on the user's system, it uses the generic algorithm, else it uses the Guava one.

Component: coding theory

Author: David Lucas

Branch/Commit: u/dlucas/covering_radius @ 15a108c

Issue created by migration from https://trac.sagemath.org/ticket/19913

[sagetrac-dlucas]

Branch: u/dlucas/covering_radius

[sagetrac-dlucas]

comment:2

I pushed the patch, this is now open for review.

---

New commits:

ce9b19c

Rewrote covering_radius method to have a non-guava implementation

[sagetrac-dlucas]

Commit: ce9b19c

[sagetrac-dlucas]

Author: David Lucas

[sagetrac-git]

Changed commit from ce9b19c to c13dc05

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

c13dc05

covering_radius is now a cached method

[sagetrac-dlucas]

comment:4

As computing the covering radius is quite slow, I made this method a cached method.
This is still open for review.

[nathanncohen]

comment:5

Could you only nest inside of the try/except what needs to be, i.e. the 'load_package' command?

As it is, any 'RuntimError' raised by another line would be interpreted as a missing package, though it may well have another cause.

Thanks,

Nathann

[nathanncohen]

comment:6

Alternatively, there is this trick that Dima used somewhere else:

if not bool(libgap.LoadPackage("grape")):
    <code>

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

37dad1a

Better test to check if Guava is installed