[SCIP] Heuristics Characters
Ahmed Ibrahim
Ahmed.Ibrahim at umanitoba.ca
Mon Feb 1 18:25:22 CET 2016
Thanks Gerald, this was helpful indeed.
Regards,
Ahmed
________________________________
From: Scip [scip-bounces at zib.de] on behalf of Gerald Gamrath [gamrath at zib.de]
Sent: Monday, February 01, 2016 5:53 AM
To: scip at zib.de
Subject: Re: [SCIP] Heuristics Characters
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
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