[SCIP] Heuristics Characters
Gerald Gamrath
gamrath at zib.de
Mon Feb 1 12:53:45 CET 2016
Dear Ahmed,
I guess you cannot print the primal heuristics via the opti toolbox, but
you could just start the SCIP binary for once and print them.
There is no list like this in the documentation, but you can have a look at
http://scip.zib.de/doc/html_devel/group__PRIMALHEURISTICS.php
where all primal heuristics are listed. Since this is the developers
manual, you can also see the corresponding .c files after two clicks
(one on the heuristic, one for the definition of the
SCIPincludeHeur...() method, where the .c file is referenced). There,
one of the first lines is #define HEUR_DISPCHAR, followed by the caracter.
Anyway, below is the current list of heuristics for SCIP 3.2.
Best,
Gerald
primal heuristic c priority freq ofs description
---------------- - -------- ---- --- -----------
ofins A 60000 -1 0 primal heuristic for
reoptimization, objective function induced neighborhood search
trivialnegation j 40000 -1 0 negate solution entries if
an objective coefficient changes the sign, enters or leaves the objective.
reoptsols J 40000 -1 0 primal heuristic updating
solutions found in a previous optimization round
trivial t 10000 0 0 start heuristic which tries
some trivial solutions
shiftandpropagate T 1000 0 0 Pre-root heuristic to expand
an auxiliary branch-and-bound tree and apply propagation techniques
zeroobj Z 100 -1 0 heuristic trying to solve
the problem without objective
simplerounding r 0 1 0 simple and fast LP rounding
heuristic
dualval Y 0 -1 0 primal heuristic using dual
values
randrounding G -200 20 0 fast LP rounding heuristic
zirounding z -500 1 0 LP rounding heuristic as
suggested by C. Wallace taking row slacks and bounds into account
rounding R -1000 1 0 LP rounding heuristic with
infeasibility recovering
shifting s -5000 10 0 LP rounding heuristic with
infeasibility recovering also using continuous variables
intshifting i -10000 10 0 LP rounding heuristic with
infeasibility recovering and final LP solving
oneopt b -20000 1 0 1-opt heuristic which tries
to improve setting of single integer variables
twoopt B -20100 -1 0 primal heuristic to improve
incumbent solution by flipping pairs of variables
indicator A -20200 1 0 indicator heuristic to
create feasible solutions from values for indicator variables
fixandinfer I -500000 -1 0 iteratively fixes variables
and propagates inferences
feaspump F -1000000 20 0 objective feasibility pump 2.0
clique Q -1000500 -1 0 LNS heuristic using a clique
partition to restrict the search neighborhood
coefdiving c -1001000 10 1 LP diving heuristic that
chooses fixings w.r.t. the matrix coefficients
pscostdiving p -1002000 10 2 LP diving heuristic that
chooses fixings w.r.t. the pseudo cost values
fracdiving f -1003000 10 3 LP diving heuristic that
chooses fixings w.r.t. the fractionalities
nlpdiving d -1003000 10 3 NLP diving heuristic that
chooses fixings w.r.t. the fractionalities
veclendiving v -1003100 10 4 LP diving heuristic that
rounds variables with long column vectors
distributiondiving e -1003300 10 3 Diving heuristic that
chooses fixings w.r.t. changes in the solution density
intdiving n -1003500 -1 9 LP diving heuristic that
fixes binary variables with large LP value to one
actconsdiving a -1003700 -1 5 LP diving heuristic that
chooses fixings w.r.t. the active constraints
objpscostdiving o -1004000 20 4 LP diving heuristic that
changes variable's objective values instead of bounds, using pseudo
costs as guide
rootsoldiving S -1005000 20 5 LP diving heuristic that
changes variable's objective values using root LP solution as guide
linesearchdiving l -1006000 10 6 LP diving heuristic that
chooses fixings following the line from root solution to current solution
guideddiving g -1007000 10 7 LP diving heuristic that
chooses fixings in direction of incumbent solutions
octane O -1008000 -1 0 octane primal heuristic for
pure {0;1}-problems based on Balas et al.
rens E -1100000 0 0 LNS exploring fractional
neighborhood of relaxation's optimum
rins N -1101000 25 0 relaxation induced
neighborhood search by Danna, Rothberg, and Le Pape
localbranching L -1102000 -1 0 local branching heuristic by
Fischetti and Lodi
mutation M -1103000 -1 8 mutation heuristic randomly
fixing variables
crossover C -1104000 30 0 LNS heuristic that fixes all
variables that are identic in a couple of solutions
dins D -1105000 -1 0 distance induced
neighborhood search by Ghosh
vbounds V -1106000 -1 0 LNS heuristic uses the
variable lower and upper bounds to determine the search neighborhood
bound H -1107000 -1 0 heuristic which fixes all
integer variables to a bound and solves the remaining LP
undercover U -1110000 0 0 solves a sub-CIP determined
by a set covering approach
proximity P -2000000 -1 0 heuristic trying to improve
the incumbent by an auxiliary proximity objective function
subnlp q -2000000 1 0 primal heuristic that
performs a local search in an NLP after fixing integer variables and
presolving
trysol y -3000000 1 0 try solution heuristic
On 31.01.2016 20:04, Ahmed Ibrahim wrote:
> Hi All,
> Is there any way I could know get a list of the primal heuristics of
> scip and their display characters other than the "display heuristics"
> command in the interactive shell? I'm using the Matlab interface "opti
> toolbox" so I don't know whether I have the option of using this
> command or not. Is there a list of those in the documentation somewhere?
>
> Regards,
> Ahmed
>
>
> _______________________________________________
> Scip mailing list
> Scip at zib.de
> http://listserv.zib.de/mailman/listinfo/scip
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