The test

            sage: g = graphs.PetersenGraph()
            sage: g.fractional_chromatic_index(solver='GLPK')
            3.0

added in src/sage/graphs/graph.py by #23658 fails with GLPK-4.63 on 32-bit.

As a workaround, we use PPL by default in #24099.

CC: @dcoudert

Component: graph theory

Author: David Coudert

Branch/Commit: public/graphs/23798_fractional_chromatic_index @ 43e8873

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/23798