get_solver should allow passing a function (a solver factory) as the solver argument

[mkoeppe]

For example, to use GLPK's exact simplex algorithm:

from sage.numerical.backends.generic_backend import get_solver
def glpk_exact_solver():
    b = get_solver(solver="GLPK")
    b.solver_parameter("simplex_or_intopt", "exact_simplex_only")
    return b

delsarte_bound_additive_hamming_space(19,15,7,solver=glpk_exact_solver)

CC: @dimpase @videlec @vbraun @jdemeyer

Component: numerical

Author: Matthias Koeppe

Branch/Commit: 37e87a5

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/20406

[mkoeppe]

Branch: u/mkoeppe/get_solver_factory

[mkoeppe]

Commit: b4146a7

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,6 +1,7 @@
 For example, to use GLPK's exact simplex algorithm:
 
 ```
+from sage.numerical.backends.generic_backend import get_solver
 def glpk_exact_solver():
     b = get_solver("GLPK")
     b.solver_parameter("simplex_or_intopt", "exact_simplex_only")

[mkoeppe]

New commits:

b4146a7

get_solver: Allow a callable as the solver argument

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

Description changed:

--- 
+++ 
@@ -3,7 +3,7 @@
 ```
 from sage.numerical.backends.generic_backend import get_solver
 def glpk_exact_solver():
-    b = get_solver("GLPK")
+    b = get_solver(solver="GLPK")
     b.solver_parameter("simplex_or_intopt", "exact_simplex_only")
     return b
 

[sagetrac-git]

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

d9ce11e

MixedIntegerLinearProgram.__copy__: Don't create a throw-away GLPK instance

[sagetrac-git]

Changed commit from b4146a7 to d9ce11e

[dimpase]

comment:6

this also needs a rebase (sorry for sitting on this too long...)

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

623a2e2	get_solver: Allow a callable as the solver argument
09377ac	MixedIntegerLinearProgram.__copy__: Don't create a throw-away GLPK instance

[sagetrac-git]

Changed commit from d9ce11e to 09377ac

[mkoeppe]

comment:8

Rebased on 7.2.beta4

[dimpase]

comment:10

without the example in the ticket description it's hard to get the idea of this change.
Can you add this example into the code?