[AMPL 2816] AMPL/CPLEX Prallele runing
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[AMPL 2816] AMPL/CPLEX Prallele runing
by Saber Jalilzadeh-Galaeh
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Dear all users I have a model which solves very huge problems in Windows. Because of that I wanna solve my model using parallel running. Is it possible? When I solved my problem in a system with 4 core I saw that AMPL/CPLEX just uses one of them. Deos AMPL/CPLEX solve problem parallel using openmpi or mpich or lam-mpi? Thanks in advance. Saber --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2817] Re: AMPL/CPLEX Prallele runing
by Ali Baharev
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[AMPL 2819] Re: AMPL/CPLEX Prallele runing
by Saber Jalilzadeh-Galaeh
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Dear Ali, Thanks for your helps. My problem is not the model. The model is several line, rather the computations with B&B is very time consuming. Let me ask my question in other way. How could I use parallel CPLEX running? would you please explain the related commands? Saber From: Ali Baharev <ali.baharev@...> To: ampl@... Sent: Tuesday, September 15, 2009 2:57:33 PM Subject: [AMPL 2817] Re: AMPL/CPLEX Prallele runing Hello, The solver (CPLEX in this case) should take advantage of multiple CPUs and not AMPL. Visit: http://www.ilog.com/optimization/the-right-hand-side/1/TA_Parallel_CPLEX_Dong.html In my opinion, it is usually more efficient (you can gain more) if you reformulate your problem in a smart way or apply some problem specific enhancement (such as cutting planes, branching heuristics). Good luck anyhow, Ali --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2820] Re: AMPL/CPLEX Prallele runing
by Robert Fourer-2
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For an explanation of options
to request parallel processing in CPLEX, look for "parallel" and
"threads" in the documentation (README.cplex and ampl110.pdf) at www.netlib.org/ampl/solvers/cplex.
For current versions of CPLEX, though, these options will only work if
your license allows parallel processing. You can tell that the license
doesn't allow parallel processing if setting the appropriate options makes no
difference, or if the license string (access.ilm) lacks a notation like
"p=4". In about a month we will
have available AMPL-CPLEX version 12 which will do parallel processing
automatically without any special license. Bob Fourer From: On Behalf Of Saber
Jalilzadeh-Galaeh [sbr_612000@...] Dear Ali, Thanks for your helps. My problem is not the model. The
model is several line, rather the computations with B&B is very time consuming. Let me ask my question in other way. How could I use parallel CPLEX
running? would you please explain the related
commands? Saber From: Ali
Baharev <ali.baharev@...> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2822] Re: AMPL/CPLEX Prallele runing
by Saber Jalilzadeh-Galaeh
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Dear Fourer Thanks a lot. Then I will wait for CPLEX 12. Saber From: Robert Fourer <4er@...> To: ampl@...; Saber Jalilzadeh-Galaeh <sbr_612000@...> Sent: Tuesday, September 15, 2009 6:54:06 PM Subject: [AMPL 2820] Re: AMPL/CPLEX Prallele runing For an explanation of options to request parallel processing in CPLEX, look for "parallel" and "threads" in the documentation (README.cplex and ampl110.pdf) at www.netlib.org/ampl/solvers/cplex. For current versions of CPLEX, though, these options will only work if your license allows parallel processing. You can tell that the license doesn't allow parallel processing if setting the appropriate options makes no difference, or if the license string (access.ilm) lacks a notation like "p=4".
In about a month we will have available AMPL-CPLEX version 12 which will do parallel processing automatically without any special license.
Bob Fourer
From: ampl@... [mailto: ampl@... ] On Behalf Of Saber
Jalilzadeh-Galaeh [sbr_612000@...]
Dear Ali,
Thanks for your helps.
My problem is not the model. The model is several line, rather the computations with B&B is very time consuming.
Let me ask my question in other way. How could I use parallel CPLEX running?
would you please explain the related commands?
Saber
From: Ali
Baharev <ali.baharev@...> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2851] Problem: Modification of CPLEX options for solutions of several MIP problems
by Pratim
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Hello, I have two MIP problems (MIP1 and
MIP2) modeled with AMPL and I want to solve them with CPLEX with different CPLEX
options. The problem is that CPLEX keeps
using the same options, i.e., those defined for the first MIP
problem. Here is the code that Iam
using. problem
MIP1; option solver cplexamp;
option cplex_options '
bestnode'; solve
MIP1; problem
MIP2; option solver cplexamp;
option cplex_options ' bestnode uppercutoff=1345'; solve
MIP2; The additional CPLEX option
‘uppercutoff=1345’ is not
taken into account by CPLEX. Indeed, CPLEX generates a number of integer
solutions with objective value strictly larger than
1346. Why is
it? How can I resolve this
issue? Best
regards, Pratim Lauren found her dream laptop. Find the PC that’s right for you. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2860] Re: Problem: Modification of CPLEX options for solutions of several MIP problems
by Robert Fourer-2
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This looks OK to me, so perhaps the whole example would be needed
to see where the difficulty lies. Note that since the problem statement
suffices to establish the current problem, it should suffice to write
"solve;" rather than "solve MIP1;" and "solve
MIP2;". I don't see why this should make a difference, though. Also
I would check the output immediately after the solve command, where CPLEX
echoes the options that are in effect. I would expect to see something
like CPLEX 11.2.0: bestnode uppercutoff=1345 Anything less would confirm that CPLEX is not recording the
options that were set. Bob Fourer From:
ampl@... [mailto:ampl@...] On Behalf Of Pratim
Vakish [pratim_usc@...] Hello, I have two MIP problems (MIP1 and
MIP2) modeled with AMPL and I want to solve them with CPLEX with different
CPLEX options. The problem is that CPLEX keeps
using the same options, i.e., those defined for the first MIP problem. Here is the code that Iam using. problem MIP1; option solver cplexamp; option cplex_options '
bestnode'; solve MIP1; problem MIP2; option solver cplexamp; option cplex_options '
bestnode uppercutoff=1345'; solve MIP2; The additional CPLEX option ‘uppercutoff=1345’ is
not taken into account by CPLEX. Indeed, CPLEX generates a number of integer
solutions with objective value strictly larger than 1346. Why is it? How can I resolve this issue? Best regards, Pratim --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2884] AMPL - GUROBI
by Pratim
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Hello, I would like to know what is the commend line to call the solver Gurobi from AMPL. Is it option_solver gurobi_cl? Also, what are the options (optimality gap, cutoff value, computing time) of the Gurobi solver that can be used with AMPL? Is there any file describing those? P Vakish Hotmail: Free, trusted and rich email service. Get it now. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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[AMPL 2885] Re: AMPL - GUROBI
by Robert Fourer-2
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The file gurobi_cl (or gurobi_cl.exe) is the command-line version
of Gurobi, which does not contain the AMPL interface. If you specifically
purchased Gurobi for AMPL, then you should have received a different executable
file for the version of Gurobi that does contain the AMPL interface. If
you downloaded the free academic version of Gurobi, then you'll have to wait a
little longer; we are working with Gurobi Optimization to provide a way for
anyone who already has AMPL to easily access the free academic version. Probably
a file gurobi_ampl (or gurobi_ampl.exe) will be added to the distribution ... but
stay tuned; we'll post the instructions. I have copied below all the Gurobi 2.0 directives that AMPL
recognizes. I'll make a web page for these to post under the Gurobi entry
at www.ampl.com/solvers.html. Bob Fourer aggregate whether
to use aggregation during Gurobi presolve
0 = no (sometimes reduces numerical errors)
1 = yes (default) basis
whether to use or return a basis:
0 = no
1 = use incoming basis (if provided)
2 = return final basis
3 = both (1 + 2 = default) bestbound whether
to return suffix .bestbound for the
best known bound on the objective value:
0 = no (default)
1 = yes cliquecuts overrides
"cuts"; choices as for "cuts" covercuts overrides
"cuts"; choices as for "cuts" cutagg
maximum number of constraint aggregation passes
during cut generation (-1 = default = no limit);
overrides "cuts" cuts
global cut generation control, valid unless overridden
by individual cut-type controls:
-1 = automatic choice (default)
0 = no cuts
1 = conservative cut generation
2 = aggressive cut generation
3 = very aggressive cut generation feastol
primal feasibility tolerance (default 1e-6) flowcover flowcover
cuts: overrides "cuts"; choices as for "cuts" flowpath
flowpath cuts: overrides "cuts"; choices as for
"cuts" gomory
maximum number of Gomory cut passes during cut generation
(-1 = default = no limit); overrides
"cuts" gubcover
gubcover cuts: overrides "cuts"; choices as for
"cuts" heurfrac
fraction of time to spend in MIP heuristics (default 0.05) iisfind
whether to return an IIS (via suffix .iis) when
the problem is infeasible:
0 = no (default)
1 ==> yes iismethod which
method to use when finding an IIS (irreducible
infeasible set of constraints, including variable
bounds):
-1 = automatic choice (default)
0 = often faster than method 1
1 = can find a smaller IIS than method 0 implied
implied cuts: overrides "cuts"; choices as for "cuts" intfeastol feasibility
tolerance for integer variables (default 1e-05) intstart
when there are integer variables, whether to use
an initial guess (if available):
0 = no
1 = yes (default) iterlim
iteration limit (default: no limit) logfile
name of file to receive log lines (default: none)
Implies outlev = 1 logfreq
interval in seconds between log lines (default 5) maxmipsub maximum
number of nodes for RIMS heuristic to explore
on MIP problems (default 500) mipgap
max. relative MIP optimality gap (default 1e-4) mipsep
MIPsep cuts: overrides "cuts"; choices as for "cuts" mipstart
whether to use initial guesses in problems with
integer variables:
0 = no
1 = yes (default) mircuts
MIR cuts: overrides "cuts"; choices as for "cuts" multprice_norm
choice of norm used in multiple pricing:
-1 = automatic choice (default)
0 = ???
1 = ???
2 = ???
3 = ??? nodefiledir
directory where MIP tree nodes are written after memory
for them exceeds nodefilestart;
default "." nodefilestart
gigabytes of memory to use for MIP tree nodes;
default = Infinity (no
limit, i.e., no node files written) nodelim
maximum MIP nodes to explore (default: no limit) normadjust synonym
for multprice_norm objno
objective to optimize:
0 = none
1 = first (default, if available),
2 = second (if available), etc. objscale
how to scale the objective:
0 ==> automatic choice (default)
negative >= -1 ==> divide by max abs.
coefficient
raised
to this power
positive ==> divide by this value opttol
optimality tolerance on reduced costs (default 1e-6) outlev
whether to write Gurobi log lines (chatter) to stdout:
0 = no (default)
1 = yes (see logfreq) perturb
magnitude of simplex perturbation (when needed; default 2e-4) pivtol
Markowitz pivot tolerance (default 7.8125e-3) presolve
whether to use Gurobi's presolve:
-1 (default) = automatic choice
0 = no
1 = conservative presolve
2 = aggressive presolve pricing
pricing strategy:
-1 = automatic choice (default)
0 = partial pricing
1 = steepest edge
2 = Devex
3 = quick-start steepest edge quad
whether simplex should use quad-precision:
-1 = automatic choice (default)
0 = no
1 = yes relax
whether to enforce integrality:
0 = yes (default)
1 = no: treat integer and binary variables
as continuous rootmethod simplex
algorithm for MIP root relaxation:
0 = primal
1 = dual (default) scale
whether to scale the problem:
0 = no
1 = yes (default) simplex
which simplex algorithm to use:
0 = primal simplex
1 = dual simplex (default) solnlimit maximum
MIP solutions to find (default 2e9) solnsens
whether to return suffixes for solution sensitivities, i.e.,
ranges of values for which the optimal basis
remains optimal:
0 = no (default)
1 = yes: suffixes return on variables
are
.sensobjlo
= smallest objective coefficient
.sensobjhi
= greatest objective coefficient
.senslblo
= smallest variable lower bound
.senslbhi
= greatest variable lower bound
.sensublo
= smallest variable upper bound
.sensubhi
= greatest variable upper bound
suffixes for constraints are
.sensrhslo
= smallest right-hand side value
.sensrhshi
= greatest right-hand side value sos
whether to honor declared suffixes .sosno and .ref describing
SOS sets:
0 = no
1 = yes (default): each distinct
nonzero .sosno value
designates
an SOS set, of type 1 for positive .sosno
values
and of type 2 for negative values. The .ref
suffix
contains corresponding reference values sos2
whether to tell GUROBI about SOS2 constraints for nonconvex
piecewise-linear terms threads
maximum threads to use on MIP problems
(default 0 ==> max possible) timelim
limit on solve time (in seconds; default: no limit) timing
whether to report timing:
0 (default) = no
1 = report times on stdout
2 = report times on stderr varbranch MIP
branch variable selection strategy:
-1 = automatic choice (default)
0 = pseudo reduced-cost branching
1 = pseudo shadow-price branching
2 = maximum infeasibility branching
3 = strong branching wantsol
solution report without -AMPL: sum of
1 ==> write .sol file
2 ==> print primal variable values
4 ==> print dual variable values
8 ==> do not print solution message writeprob name
of a GUROBI-format file to be written (for debugging);
must end in one of ".bas",
".lp", ".mps", ".prm", or ".sol";
can appear more than once (with different
filenames). zerohalfcuts
zero-half cuts: overrides "cuts"; choices as for "cuts" From: On Behalf Of Pratim
Vakish [pratim_usc@...] Hello, I
would like to know what is the commend line to call the solver Gurobi from AMPL. Is
it option_solver gurobi_cl? Also,
what are the options (optimality gap, cutoff value, computing time) of the
Gurobi solver that can be used with AMPL? Is there any file describing those? Best, --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "AMPL Modeling Language" group. To post to this group, send email to ampl@... To unsubscribe from this group, send email to ampl+unsubscribe@... For more options, visit this group at http://groups.google.com/group/ampl?hl=en -~----------~----~----~----~------~----~------~--~--- |
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