The solver "cplex" uses CPLEX (a trademark of ILOG --> IBM)
to solveinteger, mixed-integer, linear programming, and quadratic
problems,including (with version 9) problems with quadratic
constraintspossibly involving integer variables. Normally cplex is
invoked byAMPL's solve command, which gives the invocation cplex
stub -AMPLin which stub.nl is an AMPL generic output file (possibly
writtenby "ampl -obstub" or "ampl -ogstub"). After solving the
problem,cplex writes a stub.sol file for use by ampl's solve and
solutioncommands. When you run ampl, this all happens automatically
if yougive the AMPL commands option solver cplex; solve;You can
control cplex by setting the environment variable
cplex_optionsappropriately (either by using ampl's option command,
or by using theshell's set and export commands before you invoke
ampl). You can putone or more (white-space separated) phrases in
$cplex_options. A fewof the phrases are single words: Phrase
Meaning autoopt Use CPLEX's automatic choice of optimizer
(dualopt). baropt Use the barrier algorithm (unless there are
discrete variables). bestbound Return in suffix .bestbound the best
known bound on the objective value. For MIP problems with a finite
bestnode value (see below), bestbound = bestnode. bestnode For MIP
problems, return the best node value in suffix .bestnode of the
current objective and problem. For non-MIP problems and for MIP
problems for which a best node value has not yet been found, this
value is +Infinity for minimization problems and -Infinity for
maximization problems. concurrentopt When hardware and licensing
permit, try several methods in parallel (with CPLEX versions >=
8). dual Solve the dual problem. dualopt Use a dual simplex
algorithm. maximize Maximize the objective, regardless of model
specification. minimize Minimize the objective, regardless of model
specification. primal Solve the primal problem (default, via
"dualratio" described below). Note that "primal", "dual", and
"dualratio" determine what problem is presented to CPLEX, whereas
"primalopt" or "dualopt" instructs CPLEX to use a primal or dual
simplex algorithm, rather than making an automatic choice (which
currently is always "dualopt"). Thus "primalopt" and "dualopt" are
orthogonal to "primal", "dual", and "dualratio". The best settings
depend on the problem. primalopt Use a primal simplex algorithm.
relax Ignore integrality: treat integer variables as continuous.
siftopt Solve ever larger sequences of subproblems until the whole
LP is solved (versions of CPLEX >= 8). version Show the current
version.Others are name-value pairs, possibly separated by '=', as
in iterations 600or iterations=600or iterations = 600any of which
limits cplex to 600 iterations. The following names mayoccur in
name-value pairs. For convenience, the list also repeats theabove
single-word phrases, denoting them with "Single-word phrase". Name
Comment absmipgap Absolute mixed-integer optimality gap tolerance
(for difference between current best integer solution and optimal
value of LP relaxation). Default 0. advance Whether to use advance
basis information (initial primal and dual variable values and
basis indicators). Default 1 (yes). aggcutlim Bound on the number
of constraints aggregated to generate flow-cover and
mixed-integer-rounding cuts; default = 3. aggfill Synonym for
"agglim". agglim Variables that appear in more than agglim rows
(default 10) will not be substituted away by the "aggregate"
algorithm. aggregate 0 or 1 (default 1): Whether to make
substitutions to reduce the number of rows. aggtol Pivot tolerance
for aggregating. It seldom needs fiddling. Default = .05; must be
in [1e-10, .99]. autoopt Single-word phrase: use CPLEX's automatic
choice of optimizer (currently dualopt for LPs). autopt Synonym for
"autoopt". auxrootthreads New in CPLEX 12.2. Controls the number of
threads used for auxiliary chores when solving the root node of a
MIP problem. When N threads are available (possibly limited by
"threads"), auxrootthreads must be less than N. Possible values: -1
= automatic choice (default) 0 = none for concurrent executions n
< N: use N-n threads for the root node and n threads for
auxiliary chores. backtrack Tolerance (> 0, default 0.9999) for
when to backtrack during branch & bound. Low values tend to
pure best-bound search. High values (> 1) tend to pure
depth-first search. Values less than the default are often good
when subproblems are expensive. baralg How to start the barrier
algorithm: 0 (default) = 1 for MIP subproblems, else 3 1 =
infeasibility-estimate start 2 = infeasibility-constant start 3 =
standard start. barcorr Limit on centering corrections in each
iteration of the barrier algorithm: -1 = decide automatically
(default) nonnegative = at most that many. bardisplay Specifies how
much the barrier algorithm chatters: 0 = no output (default) 1 =
one line per iteration 2 = more output. bargrowth Tolerance for
detecting unbounded faces in the barrier algorithm: higher values
make the test for unbounded faces harder to satisfy. Default =
1e12. bariterlim Maximum barrier iterations allowed (default 200).
barobjrange Limit on the absolute objective value before the
barrier algorithm considers the problem unbounded. Default = 1e20.
baropt Single-word phrase: use the barrier algorithm (unless there
are discrete variables). baroutofcore New in CPLEX 7.1: whether the
barrier solver should use disk (out-of-core) storage for Cholesky
factors: 0 = no (default) 1 = yes. Withdrawn in CPLEX 10.0.
barstart Barrier starting-point algorithm: 1 = dual is 0 (default)
2 = estimate dual 3 = average of primal estimate, 0 dual 4 =
average of primal and dual estimates. barstartalg Synonym for
"barstart". barthreads Maximum threads for the barrier algorithm (1
unless you have a CPLEX license for multiple threads). Withdrawn
from CPLEX 11. barvarup Upper bound imposed by barrier algorithm on
variables with infinite upper bound; used to prevent trouble with
problems having unbounded optimal faces. Default = 1e20. Withdrawn
from CPLEX 9.0. basis_cond Whether to show the condition number of
the simplex basis in the solve_message and to return its value in
the problem.basis_cond and objective.basis_cond suffixes. (Default
= 0 = no; 1 = yes). basisinterval Number of interations between
savings of current simplex basis to a file. Default = 50000.
Deprecated in 10.0, removed in 12.6.1. bbinterval For nodeselect =
2, select the best-bound node, rather than the best-estimate node,
every bbinterval iterations (default 7); 0 means always use the
best-estimate node. bestbound Single-word phrase requesting return
of .bestbound suffix. See the description above. bestnode
Single-word phrase requesting return of .bestnode suffix. See the
description above. boundstr Whether to use bound strengthening in
solving MIPs: -1 (default) = automatic choice 0 = never 1 = always.
branch Branching direction for integer variables: -1 = down, 0 =
algorithm decides, 1 = up; default = 0. branchdir Synonym for
"branch". cliquecuts Synonym for "cliques". cliques Whether to use
clique cuts in solving MIPs: -1 = never 0 = automatic choice
(default) 1, 2, 3 = ever more aggressive generation. clocktype Kind
of times CPLEX reports during the solution process: 1 = CPU time
(default) 2 = wall clock time (total elapsed time). coeffreduce
Whether to use coefficient reduction when preprocessing MIPS: 0 =
no 1 = yes (default). comptol Convergence tolerance for barrier
algorithm: the algorithm stops when the relative complementarity is
< bartol (default 1e-8). concurrentopt Single-word phrase: with
CPLEX versions >= 8 and when hardware and licensing permit, try
several methods in parallel. conflictalg Choice of algorithm used
by the CPLEX's conflict refiner (new in 12.6.1): 0 = automatic
choice (default) 1 = fast 2 = propagate 3 = presolve 4 = IIS 5 =
limited solve 6 = full solve. Settings 1, 2, and 3 are fast but may
not discard many constraints; 5 and 6 work harder at this. Setting
4 searches for an Irreducible Infeasible Set of linear constraints
(e.g., ignoring quadratic constraints). conflictdisplay New in
CPLEX 10.0. What to report when the conflict finder is working: 0 =
nothing 1 = summary (default) 2 = detailed display. covercuts
Synonym for "covers". covers Whether to use cover cuts in solving
MIPs: -1 = never 0 = automatic choice (default) 1, 2, 3 = ever more
aggressive generation. crash Crash strategy (used to obtain
starting basis); possible values = -1, 0, 1; default = 1. The best
setting is problem-dependent and can only be found by
experimentation. 0 completely ignores the objective. crossover
Causes the barrier algorithm to be run (in the absence of discrete
variables) and specifies whether to "crossover" to an optimal
simplex basis afterwards: 0 = no crossover 1 = crossover with
primal simplex (default for baropt) 2 = crossover with dual
simplex. cutpass Number of passes permitted when generating MIP
cutting plane: -1 = none 0 = automatic choice (default) positive =
at most that many passes cutsfactor Limit MIP cuts added to
(cutsfactor-1)*m, where m is the original number of rows (after
presolve). Default = 4. cutstats 0 or 1 (default 0): Whether the
solve_message report the numbers and kinds of cuts used. dense
Synonym for "densecol". densecol If positive, minimum nonzeros in a
column for the barrier algorithm to consider the column dense. If 0
(default), this tolerance is selected automatically. dependency
Whether to use CPLEX's presolve dependency checker: 0 = no
(default) 1 = turn on only at start of preprocessing 2 = turn on
only at end of preprocessing 3 = turn on at both start and end of
preprocessing. dettimelim Time limit in platform-dependent "ticks".
New in CPLEX 12.5; see timing. dgradient Pricing algorithm for dual
simplex (default 0): 0 = choose automatically 1 = standard dual
pricing 2 = steepest-edge pricing 3 = steepest-edge pricing in
slack space 4 = steepest-edge with unit initial norms 5 = devex
pricing. disjcuts Whether to generate MIP disjunctive cuts: -1 = no
0 = automatic choice (default) 1, 2, 3 = ever more aggressive
generation. display Frequency of displaying LP progress
information: 0 (default) = never 1 = each factorization 2 = each
iteration. doperturb 1 means initially perturb the problem (by an
amount governed by "perturbation", which is described below). 0
(default) means let the algorithm decide. Setting doperturb to 1 is
occasionally helpful for highly degenerate problems. dparam Used
with syntax "dparam=n=d" (no spaces), where n is a decimal integer,
the number of a CPLEX "double" (i.e., floating-point valued)
parameter. If d is a decimal floating-point value, assign d to
"double" parameter n. If d is ?, report the current value of
"double" paramter n. This facility provides a way to modify
"double" parameters that have not (yet) been assigned a keyword.
droptol If droptol > 0 is specified, linear constraint and
objective coefficients less than droptol in magnitude are treated
as zero. New in CPLEX 11. dual Single-word phrase: solve the dual
problem. dualopt Single-word phrase: use a dual simplex algorithm.
dualratio If neither "primal" nor "dual" was specified and "dual"
is possible (e.g., no integer variables and no node and arc
declarations), choose between "primal" and "dual" as follows. Let m
= number of rows, n = number of columns; if m - n > dualthresh
> 0 or m > dualratio*n, solve the dual; otherwise solve the
primal. Defaults: dualthresh = 0, dualratio = 3. dualthresh See
dualratio. eachcutlim Limit on the number of cuts of each time.
Default = 2100000000. New in CPLEX 11. endbasis "endbasis foo"
writes the final basis to file "foo" (in BAS format). endsol File
for writing the final solution as an XML file. endtree File for
writing final branch & bound search tree. Withdrawn from CPLEX
10. endvector File for writing solution from barrier algorithm
without crossover: only meaningful with "baropt crossover=0".
Deprecated; use endsol instead. feasibility Amount by which basic
variables can violate their bounds. Default = 1e-6; possible values
are between 1e-9 and 1e-4. feasopt New in CPLEX 10.0. For
infeasible problems, whether to find a feasible point for a relaxed
problem (see feasoptobj): 0 = no (default) 1 = find a feasible
point 2 = find a "best" feasible point. feasoptobj New in CPLEX
10.0. Objective for "feasopt": 1 = minimize sum of constraint and
variable bound relaxations 2 = minimize number of constraint and
variable bounds relaxed (a MIP problem, generally harder than
feasoptobj = 1) 3 = minimize sum of squares of constraint and
variable bound relaxations. file Synonym for "writeprob".
finalfactor Whether to factor the basis after "uncrushing" the
problem at the end. 0 = no 1 = yes (default) Withdrawn in CPLEX
10.0. flowcuts Whether to use flow cuts in solving MIPs: -1 = never
0 = automatic choice (default) 1, 2 = ever more aggressive use.
flowpathcuts Whether to generate MIP flow-path cuts: -1 = no 0 =
automatic choice (default) 1, 2 = ever more aggressive generation.
fpheur Whether to use the feasibility pump heuristic on MIP
problems: -1 = no 0 = automatic choice (default) 1 = yes, focus on
finding a feasible solution 2 = yes, focus on finding a good
objective value at a feasible solution. New in CPLEX 11. fraccand
Limit on number of candidate variables when generating Gomory cuts
for MIP problems: default = 200. fraccuts Whether to generate MIP
fractional Gomory cuts: -1 = no 0 = decide automatically (default)
1 = generate moderately 2 = generate aggressively. fracpass Limit
on number of passes to generate MIP fractional Gomory cuts: 0 =
automatic choice (default) positive = at most that many passes.
fractionalcuts Synonym for "fracpass". growth Synonym for
"bargrowth". gubcuts Whether to use GUB cuts in solving MIPs: -1 =
never 0 = automatic choice (default) 1, 2 = ever more aggressive
generation. heurfreq How often to apply "node heuristics" for MIPS:
-1 = never 0 = automatic choice (default) n > 0 = every n nodes.
heuristic Deprecated: withdrawn from CPLEX 9.0. What heuristic to
use on MIPS for finding an initial integer solution: -1 = none 0 =
decide automatically (default) 1 = use a rounding heuristic at node
0. heuristicfreq Synonym for "heurfreq". iisfind Whether to find
and return an IIS (irreducible infeasible set of variables and
constraints) if the problem is infeasible: 0 = no (default) 1 =
find an IIS. IIS details are returned in suffix .iis, which assumes
one of the values "non" for variables and constraints not in the
IIS; "low" for variables or inequality constraint bodies whose
lower bounds are in the IIS; "upp" for variables and inequality
constraint bodies whose upper bounds are in the IIS; and "fix" for
equality constraints that are in the IIS. impliedcuts Whether to
use implied cuts in solving MIPs: -1 = never 0 = automatic choice
(default) 1, 2 = ever more aggressive use. incompat How to treat
parameter settings that CPLEX finds incompatible: 0 = quietly
ignore incompatibilities 1 = report and ignore them (default) 2 =
reject them, refusing to solve. For example, CPLEX regards the
polishafter_* parameters introduced in CPLEX 11.2 as incompatible
with the older polishtime parameter. integrality Amount by which an
integer variable can differ from the nearest integer and still be
considered feasible. Default = 1e-5; must be in [1e-9, 0.5]. (The
upper bound was not enforced prior to CPLEX 11.) intwarntol Do not
warn about perturbations to "integer" variables to make them
integers when the maximum perturbation is at most intwarntol
(default 1e-9); see "round". iparam Used with syntax "iparam=n=i"
(no spaces), where n is a decimal integer, the number of a CPLEX
integer parameter. If i is a decimal integer, assign i to integer
parameter n. If i is ?, report the current value of integer
paramter n. This facility provides a way to modify integer
parameters that have not (yet) been assigned a keyword. iterations
Limit on total LP iterations; default 5000000. iterlim Synonym for
"iterations". lazy Whether to recognize suffix .lazy on constraints
(new for CPLEX 10): sum of 1 ==> treat .lazy = 1 as lazy
constraint 2 ==> treat .lazy = 2 as user cut Default lazy = 3
==> treat both. (Suffix .lazy on constraints is ignored if not
0, 1, or 2 modulo 3.) lbheur Whether to use a local branching
heuristic in an attempt to improve new incumbents found during a
MIP search. (Default = 0 = no; 1 = yes.) limitperturb Synonym for
"perturblimit". localimpliedcuts Whether to generate locally valid
implied bound cuts for MIP problems (new in 12.6.1): -1 ==> no 0
==> automatic choice (default) 1 ==> yes, moderately 2 ==>
yes, aggressively 3 ==> yes, very aggressively. logfile Name of
file to receive all CPLEX messages. lowercutoff For maximization
problems involving integer variables, skip any branch whose LP
relaxation's optimal value is less than lowercutoff. Warning: if
lowercutoff is too large, the problem will appear infeasible.
Default = -Infinity. lowerobj Stop minimizing when the objective
value goes below lowerobj. Default = -1e75. lowerobjlim Synonym for
"lowerobj". lpdisplay Synonym for "display". lpiterlim Synonym for
"iterations". lptimelim Synonym for "time". markowitz Pivot
tolerance; default = 0.01; must be between 0.0001 and 0.99999.
Bigger values may improve numerical properties of the solution (and
may take more time). maximize Single-word phrase: maximize the
objective, regardless of model specifications. mcfcuts New in CPLEX
12.0. Whether to use multi-commodity flow (MCF) cuts: -1 = no 0 =
let CPLEX decide (default) 1 = generate a modest number of MCS cuts
2 = generate MCS cuts aggressively. memoryemphasis New in CPLEX
10.0. Whether to compress data to reduce the memory used, which may
make some information (e.g., basis condition) unavailable: 0 = no
(default) 1 = yes. minimize Single-word phrase: minimize the
objective, regardless of model specifications. mipalg Algorithm
used on mixed-integer subproblems (default 2): 1 = primal simplex 2
= dual simplex (plus primal, if dual fails) 3 = network alg., then
dual simplex 4 = barrier with crossover The next two are not
available in CPLEX versions >= 8; specify mipcrossover instead.
5 = dual to iteration limit, then barrier 6 = barrier without
crossover. mipalgorithm Synonym for "mipalg". mipbasis Whether to
compute a basis and dual variables for MIP problems when endbasis
is not specified: 0 = no 1 = yes This keyword is new with driver
version 20040716. When endbasis is specified, mipbasis=1 is
assumed. Otherwise, when mipbasis=0 is specified for a MIP problem,
no solver-status values for variables are returned to AMPL. The
default is 1 unless a quadratic objective or constraints are
present, in which case the default is 0 (as finding a basis can be
time consuming). mipcrossover Crossover method used when using the
barrier method for MIP subproblems: -1 = no crossover 0 (default) =
automatic choice 1 = primal 2 = dual. mipcuts Sets all ten of
cliques, covers, disjcuts, flowcuts, flowpathcuts, fraccuts,
gubcuts, impliedcuts, mircuts and zerohalfcuts to the specified
value. mipdisplay Frequency of displaying branch-and-bound
information (for optimizing integer variables): 0 (default) = never
1 = each integer feasible solution 2 = every "mipinterval" nodes 3
= every "mipinterval" nodes plus information on LP relaxations (as
controlled by "display") 4 = same as 2, plus LP relaxation info 5 =
same as 2, plus LP subproblem info. mipemphasis Whether to
emphasize seeking optimality (0 = default) or finding feasible
solutions (1). For CPLEX versions >= 8, two other values are
possible: emphasizing optimality over feasibility (2) and
emphasizing best bound (3). mipgap Relative tolerance for
optimizing integer variables: stop if abs((best bound) - (best
integer)) < mipgap * (1 + abs(best bound)). Default = 1e-4; must
be between 1e-9 and 1. mipinterval Frequency of node logging for
mipdisplay 2 or 3. Default = 1. mipkappa Whether to compute
statistics on the condition numbers of optimal simplex bases for
subproblems seen when solving a MIP problem. (This is not relevant
to the sifting algorithm or the barrier algorithm without
crossover.) New in CPLEX 12.2; can be expensive. Possible values:
-1 = no mipkappa computations (default) 0 = automatic choice 1 =
compute for a sample of subproblems 2 = compute for all
subproblems. If available, statistics are reported in the
solve_message. mipordertype Synonym for "ordertype". mipsearch
Search strategy for mixed-integer problems, new in CPLEX 11: 0 =
automatic choice (default) 1 = traditional branch and cut 2 =
dynamic search. mipsolutions Stop branch-and-bound for integer
variables after finding "mipsolutions" feasible solutions. Default
= 2100000000. mipstart Synonym for "mipstartvalue". mipstartalg
Which LP algorithm to use in solving the initial MIP subproblem: 1
= primal simplex 2 = dual simplex (default) 3 = netopt 4 = barrier
with crossover The next two are not available in CPLEX versions
>= 8; specify mipcrossover instead. 5 = dual simplex to
iteration limit, then barrier 6 = barrier without crossover.
mipstartstatus Whether to use incoming variable and constraint
statuses if the problem has integer variables: 0 = no 1 = yes
(default). mipstartvalue Whether to use initial guesses in problems
with integer variables: 0 = no 1 = yes (default) 2 = yes, using the
deprecated CPXcopymipstart function (as formerly done), rather than
the now preferred CPXaddmipstarts (starting with driver version
20110607); this is for debugging and is to be withdrawn. mipsubalg
Synonym for "mipalg". mipthreads Maximum threads for the MIP
algorithm (1 unless you have a CPLEX license for multiple threads).
Withdrawn from CPLEX 11. miqcpstrat Strategy for solving
quadratically-constrained MIPs (MIQCP problems): 0 = automatic
choice (default) 1 = solve a quadratically-constrained node
relaxation (QCP) at each node 2 = solve an LP node relaxation at
each node New in CPLEX 11. mircuts Whether to generate MIP rounding
cuts: -1 = no 0 = automatic choice (default) 1 = moderate
generation 2 = aggressive generation. nameround Whether to mangle
variable and constraint names by turning [ and ] into ( and ),
respectively: 0 = no (default) 1 = yes. This only matters if you
specify endbasis=... or startbasis=... or perhaps
writeprob=something.lp and have instructed AMPL to write .row and
.col files. (It is usually better to let AMPL's status facilities
convey basis information.) An alternative under Unix is to use the
"tr" command to make the above changes if they are needed.
netdisplay Which objective value to show when using the network
simplex algorithm with display > 0 or netopt=3: 0 = none 1 =
true objective 2 = penalized objective (default). netfeasibility
Feasibility tolerance for the network simplex algorithm. Default =
1e-6; possible values are between 1e-11 and 1e-1. netfind Algorithm
for finding embedded networks: 1 = extract only the natural network
(default) 2 = use reflection scaling 3 = use general scaling.
netfinder Synonym for "netfind". netiterations Limit on network
simplex iterations. Default = large (e.g., 2100000000). netopt 0
means never invoke the network optimizer. 1 (default) means invoke
the network optimizer only if the model had node and arc
declarations. 2 means always invoke the network optimizer (unless
there are integer variables); the network optimizer may be able to
find and exploit an embedded network. 3 is similar to 2, but sets
CPLEX's LPMethod to CPX_ALG_NET rather than explicitly invoking the
network optimizer. This might make a difference if CPLEX's presolve
makes relevant reductions. netoptimality Tolerance for optimality
of reduced costs in the network simplex algorithm. Default 1e-6;
must be between 1e-11 and 1e-1. netpricing How to price in the
network simplex algorithm: 0 = automatic choice (default) 1 =
partial pricing 2 = multiple partial pricing 3 = multiple partial
pricing with sorting. node Synonym for "nodes". nodefile Whether to
save node information in a temporary file: 0 = no 1 (default) =
compressed node file in memory 2 = node file on disk 3 = compressed
node file on disk. nodefiledir Synonym for workfiledir. Prior to
CPLEX 7.1, this directory is just for node information files.
nodefilelim Maximum size for the node file. Default 1e75. Removed
from CPLEX 7.1. See workfilelim. nodefilesize Synonym for
"nodefilelim". nodelim Synonym for "nodes". nodes Stop
branch-and-bound for integer variables after "nodes" LP
relaxations. Default = 2100000000. New in CPLEX 11: nodes = 0
==> complete processing at the root (create cuts, apply
heuristics at root); 1 ==> allow branching from root: create but
do not solve nodes. nodesel Strategy for choosing next node while
optimizing integer variables: 0 = depth-first search; 1 =
breadth-first search (default); 2 = best-estimate search; 3 =
alternate best-estimate search. nodeselect Synonym for "nodesel".
numericalemphasis New in CPLEX 10.0. Whether to try to improve
numerical accuracy (at a possible cost of time or memory): 0 = no
(default) 1 = yes. objdifference Amount added to (for maximizing)
or subtracted from (for minimizing) the best (so far) feasible
objective value while optimizing integer variables. Subsequent
nodes will be ignored if their LP relaxations have optimal values
worse than this sum. Default = 0. Positive values may speed the
search -- and may cause the optimal solution to be missed. objno 1
(default) = first objective, 2 = second, etc.; 0 ==> no
objective: just find a feasible point. objrep Whether to replace
minimize obj: v; with minimize obj: f(x) when variable v appears
linearly in exactly one constraint of the form s.t. c: v >=
f(x); or s.t. c: v == f(x); Possible objrep values: 0 = no 1 = yes
for v >= f(x) 2 = yes for v == f(x) (default) 3 = yes in both
cases For maximization problems, ">= f(x)" is changed to
">times&to solve a problem whose solution will take a while;
after cplexfinishes, ampl foo.model foo.data - solution foo.sol;
display ... /* things involving the computed solution */;(Here, -
denotes standard input, and ampl reads the "solution..."and
"display..." lines.)When invoked with no arguments, cplex either
operates as describedin the CPLEX manual (when compiled with
-DStand_alone on systemswhere the CPLEX callable library provides
cpxmain()), or complainsabout not having a
stub.-------------------In addition to the keyword phrases
described above, cplex recognizessome directives (name-value pairs,
separated by white space and/or an= sign, appearing either in
$cplex_options or on the command line) forsettings not described in
the official CPLEX documentation. These"undocumented" directives
all begin with underscore. You are unlikelyever to need to use
them, as the default settings suffice in mostcases. They are
provided for the rare cases where CPLEX technicalsupport may
recommend their use. The directive names appear at thebeginning of
the output you will get by invoking cplex "-="(or 'cplexamp "-="'
if you follow the IBM ILOG naming practice).Starting with updates
for CPLEX 12.6.1, the "cplex -=" output includesvariants of the
above keyword descriptions just for the currentlyavailable
keywords.*************************If you have questions about or
find bugs with this stuff,please contact: David M. Gay
[email protected]
