pulp.apis Interface to Solvers

class pulp.apis.CHOCO_CMD(path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None)

Bases: LpSolver_CMD

The CHOCO_CMD solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• options (list) – list of additional options to pass to solver

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name = 'CHOCO_CMD'

static readsol(filename)

Read a Choco solution file

pulp.apis.COIN

alias of COIN_CMD

class pulp.apis.COINMP_DLL(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The COIN_MP LP MIP solver (via a DLL or linux so)

Parameters:

• timeLimit (float) – The number of seconds before forcing the solver to exit

• epgap – The fractional mip tolerance

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp)

Solve a well formulated lp problem

classmethod available()

True if the solver is available

name = 'COINMP_DLL'

pulp.apis.COINMP_DLL_load_dll(path)

function that loads the DLL useful for debugging installation problems

class pulp.apis.COIN_CMD(mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, presolve=None, cuts=None, strong=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, timeMode='elapsed', maxNodes=None)

Bases: LpSolver_CMD

The COIN CLP/CBC LP solver now only uses cbc

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• threads (int) – sets the maximum number of threads

• options (list) – list of additional options to pass to solver

• warmStart (bool) – if True, the solver will use the current value of variables as a start

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

• logPath (str) – path to the log file

• presolve (bool) – if True, adds presolve on, if False, adds presolve off

• cuts (bool) – if True, adds gomory on knapsack on probing on, if False adds cuts off

• strong (int) – number of variables to look at in strong branching (range is 0 to 2147483647)

• timeMode (str) – “elapsed”: count wall-time to timeLimit; “cpu”: count cpu-time

• maxNodes (int) – max number of nodes during branching. Stops the solving when reached.

actualSolve(lp, **kwargs)

Solve a well formulated lp problem

available()

True if the solver is available

copy()

Make a copy of self

defaultPath()

getOptions()

get_status(filename)

name = 'COIN_CMD'

readsol_LP(filename, lp, vs)

Read a CBC solution file generated from an lp (good names) returns status, values, reducedCosts, shadowPrices, slacks, sol_status

readsol_MPS(filename, lp, vs, variablesNames, constraintsNames, objectiveName=None)

Read a CBC solution file generated from an mps or lp file (possible different names)

solve_CBC(lp, use_mps=True)

Solve a MIP problem using CBC

writesol(filename, lp, vs, variablesNames, constraintsNames)

Writes a CBC solution file generated from an mps / lp file (possible different names) returns True on success

class pulp.apis.COPT(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The COPT Optimizer via its python interface

The COPT variables are available (after a solve) in var.solverVar Constraints in constraint.solverConstraint and the Model is in prob.solverModel

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp, callback=None)

Solve a well formulated lp problem

available()

True if the solver is available

name = 'COPT'

class pulp.apis.COPT_CMD(path=None, keepFiles=0, mip=True, msg=True, mip_start=False, warmStart=False, logfile=None, **params)

Bases: LpSolver_CMD

The COPT command-line solver

Initialize command-line solver

actualSolve(lp)

Solve a well formulated LP problem

This function borrowed implementation of CPLEX_CMD.actualSolve and GUROBI_CMD.actualSolve, with some modifications.

available()

True if ‘copt_cmd’ is available

defaultPath()

The default path of ‘copt_cmd’

name = 'COPT_CMD'

readsol(filename)

Read COPT solution file

writemst(filename, lpvars)

Write COPT MIP start file

class pulp.apis.COPT_DLL(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The COPT dynamic library solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

err = TypeError('expected str, bytes or os.PathLike object, not NoneType')

name = 'COPT_DLL'

pulp.apis.COPT_DLL_loadlib()

Load COPT shared library in all supported platforms

pulp.apis.CPLEX

alias of CPLEX_CMD

class pulp.apis.CPLEX_CMD(mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, maxMemory=None, maxNodes=None)

Bases: LpSolver_CMD

The CPLEX LP solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• threads (int) – sets the maximum number of threads

• options (list) – list of additional options to pass to solver

• warmStart (bool) – if True, the solver will use the current value of variables as a start

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

• logPath (str) – path to the log file

• maxMemory (float) – max memory to use during the solving. Stops the solving when reached.

• maxNodes (int) – max number of nodes during branching. Stops the solving when reached.

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

getOptions()

name = 'CPLEX_CMD'

readsol(filename)

Read a CPLEX solution file

writesol(filename, vs)

Writes a CPLEX solution file

class pulp.apis.CPLEX_PY(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The CPLEX LP/MIP solver (via a Python Binding)

This solver wraps the python api of cplex. It has been tested against cplex 12.3. For api functions that have not been wrapped in this solver please use the base cplex classes

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

err = ModuleNotFoundError("No module named 'cplex'")

name = 'CPLEX_PY'

pulp.apis.FSCIP

alias of FSCIP_CMD

class pulp.apis.FSCIP_CMD(path=None, mip=True, keepFiles=False, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, maxNodes=None, threads=None, logPath=None)

Bases: LpSolver_CMD

The multi-threaded FiberSCIP version of the SCIP optimization solver

Parameters:

• msg (bool) – if False, no log is shown

• mip (bool) – if False, assume LP even if integer variables

• options (list) – list of additional options to pass to solver

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• maxNodes (int) – max number of nodes during branching. Stops the solving when reached.

• threads (int) – sets the maximum number of threads

• logPath (str) – path to the log file

FSCIP_STATUSES = {'Final Solution': 1, 'No Solution': 0}

NO_SOLUTION_STATUSES = {-2, -1, 0}

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name = 'FSCIP_CMD'

static parse_objective(string: str) → float | None

static parse_status(string: str) → int | None

static parse_variable(string: str) → Tuple[str, float] | None

static readsol(filename)

Read a FSCIP solution file

pulp.apis.GLPK

alias of GLPK_CMD

class pulp.apis.GLPK_CMD(path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None)

Bases: LpSolver_CMD

The GLPK LP solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• options (list) – list of additional options to pass to solver

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name = 'GLPK_CMD'

readsol(filename)

Read a GLPK solution file

class pulp.apis.GUROBI(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The Gurobi LP/MIP solver (via its python interface)

The Gurobi variables are available (after a solve) in var.solverVar Constraints in constraint.solverConstraint and the Model is in prob.solverModel

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp, callback=None)

Solve a well formulated lp problem

available()

True if the solver is available

env = None

name = 'GUROBI'

class pulp.apis.GUROBI_CMD(mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, mip_start=False)

Bases: LpSolver_CMD

The GUROBI_CMD solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• threads (int) – sets the maximum number of threads

• options (list) – list of additional options to pass to solver

• warmStart (bool) – if True, the solver will use the current value of variables as a start

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

• logPath (str) – path to the log file

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

getOptions()

name = 'GUROBI_CMD'

readsol(filename)

Read a Gurobi solution file

writesol(filename, vs)

Writes a GUROBI solution file

class pulp.apis.HiGHS(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp, callback=None)

Solve a well formulated lp problem

available()

True if the solver is available

name = 'HiGHS'

class pulp.apis.HiGHS_CMD(path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, threads=None, logPath=None, warmStart=False)

Bases: LpSolver_CMD

The HiGHS_CMD solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• options (list[str]) – list of additional options to pass to solver

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary (you can get binaries for your platform from https://github.com/JuliaBinaryWrappers/HiGHS_jll.jl/releases, or else compile from source - https://highs.dev)

• threads (int) – sets the maximum number of threads

• logPath (str) – path to the log file

• warmStart (bool) – if True, the solver will use the current value of variables as a start

SOLUTION_STYLE: int = 0

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name: str = 'HiGHS_CMD'

readsol(filename)

Read a HiGHS solution file

writesol(filename, lp)

Writes a HiGHS solution file

class pulp.apis.LpSolver(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: object

A generic LP Solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualResolve(lp, **kwargs)

uses existing problem information and solves the problem If it is not implemented in the solver just solve again

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

copy()

Make a copy of self

getCplexStyleArrays(lp, senseDict=None, LpVarCategories=None, LpObjSenses=None, infBound=1e+20)

returns the arrays suitable to pass to a cdll Cplex or other solvers that are similar

Copyright (c) Stuart Mitchell 2007

name = 'LpSolver'

solve(lp)

Solve the problem lp

toDict()

toJson(filename, *args, **kwargs)

to_dict()

to_json(filename, *args, **kwargs)

class pulp.apis.LpSolver_CMD(path=None, keepFiles=False, *args, **kwargs)

Bases: LpSolver

A generic command line LP Solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list) – list of additional options to pass to solver (format depends on the solver)

• timeLimit (float) – maximum time for solver (in seconds)

• path (str) – a path to the solver binary

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• args – parameters to pass to LpSolver

• kwargs – parameters to pass to LpSolver

copy()

Make a copy of self

create_tmp_files(name, *args)

defaultPath()

delete_tmp_files(*args)

static executable(command)

Checks that the solver command is executable, And returns the actual path to it.

static executableExtension(name)

name = 'LpSolver_CMD'

setTmpDir()

Set the tmpDir attribute to a reasonnable location for a temporary directory

silent_remove(file: str | bytes | PathLike) → None

class pulp.apis.MIPCL_CMD(path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None)

Bases: LpSolver_CMD

The MIPCL_CMD solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• options (list) – list of additional options to pass to solver

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name = 'MIPCL_CMD'

static readsol(filename)

Read a MIPCL solution file

class pulp.apis.MOSEK(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

Mosek lp and mip solver (via Mosek Optimizer API).

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp, callback=None)

Solves a well-formulated lp problem.

available()

True if Mosek is available.

name = 'MOSEK'

class pulp.apis.PULP_CBC_CMD(mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, presolve=None, cuts=None, strong=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, timeMode='elapsed', maxNodes=None)

Bases: COIN_CMD

This solver uses a precompiled version of cbc provided with the package

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• threads (int) – sets the maximum number of threads

• options (list) – list of additional options to pass to solver

• warmStart (bool) – if True, the solver will use the current value of variables as a start

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

• logPath (str) – path to the log file

• presolve (bool) – if True, adds presolve on, if False, adds presolve off

• cuts (bool) – if True, adds gomory on knapsack on probing on, if False adds cuts off

• strong (int) – number of variables to look at in strong branching (range is 0 to 2147483647)

• timeMode (str) – “elapsed”: count wall-time to timeLimit; “cpu”: count cpu-time

• maxNodes (int) – max number of nodes during branching. Stops the solving when reached.

name = 'PULP_CBC_CMD'

pulp_cbc_path = '/home/runner/work/pulp/pulp/pulp/solverdir/cbc/linux/64/cbc'

class pulp.apis.PYGLPK(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The glpk LP/MIP solver (via its python interface)

Copyright Christophe-Marie Duquesne 2012

The glpk variables are available (after a solve) in var.solverVar The glpk constraints are available in constraint.solverConstraint The Model is in prob.solverModel

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp, callback=None)

Solve a well formulated lp problem

available()

True if the solver is available

name = 'PYGLPK'

pulp.apis.Parser

alias of ConfigParser

exception pulp.apis.PulpSolverError

Bases: PulpError

Pulp Solver-related exceptions

class pulp.apis.SAS94(mip=True, msg=True, warmStart=False, keepFiles=False, timeLimit=None, **solverParams)

Bases: SASsolver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• warmStart (bool) – if False, no warm start

• keepFiles (bool) – if False, the generated mps mst files will be removed

• solverParams – SAS proc OPTMILP or OPTLP parameters

actualSolve(lp, callback=None)

Solves a well-formulated lp problem.

available()

True if SAS94 is available.

name = 'SAS94'

class pulp.apis.SASCAS(mip=True, msg=True, warmStart=False, keepFiles=False, timeLimit=None, **solverParams)

Bases: SASsolver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• warmStart (bool) – if False, no warm start

• keepFiles (bool) – if False, the generated mps mst files will be removed

• solverParams – SAS proc OPTMILP or OPTLP parameters

actualSolve(lp, callback=None)

Solves a well-formulated lp problem.

available()

True if SASCAS is available.

name = 'SASCAS'

class pulp.apis.SASLogWriter(tee)

Bases: object

flush()

log()

write(message)

class pulp.apis.SASsolver(mip=True, msg=True, warmStart=False, keepFiles=False, timeLimit=None, **solverParams)

Bases: LpSolver_CMD

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• warmStart (bool) – if False, no warm start

• keepFiles (bool) – if False, the generated mps mst files will be removed

• solverParams – SAS proc OPTMILP or OPTLP parameters

defaultPath()

name = 'SASsolver'

pulp.apis.SCIP

alias of SCIP_CMD

class pulp.apis.SCIP_CMD(path=None, mip=True, keepFiles=False, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, maxNodes=None, logPath=None, threads=None)

Bases: LpSolver_CMD

The SCIP optimization solver

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list) – list of additional options to pass to solver

• keepFiles (bool) – if True, files are saved in the current directory and not deleted after solving

• path (str) – path to the solver binary

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• gapAbs (float) – absolute gap tolerance for the solver to stop

• maxNodes (int) – max number of nodes during branching. Stops the solving when reached.

• threads (int) – sets the maximum number of threads

• logPath (str) – path to the log file

NO_SOLUTION_STATUSES = {-2, -1, 0}

SCIP_STATUSES = {'gap limit reached': 1, 'infeasible': -1, 'infeasible or unbounded': 0, 'memory limit reached': 0, 'node limit reached': 0, 'optimal solution found': 1, 'restart limit reached': 0, 'solution improvement limit reached': 0, 'solution limit reached': 0, 'stall node limit reached': 0, 'time limit reached': 0, 'total node limit reached': 0, 'unbounded': -2, 'unknown': -3, 'user interrupt': 0}

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name = 'SCIP_CMD'

static readsol(filename)

Read a SCIP solution file

class pulp.apis.SCIP_PY(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

The SCIP Optimization Suite (via its python interface)

The SCIP internals are available after calling solve as: - each variable in variable.solverVar - each constraint in constraint.solverConstraint - the model in problem.solverModel

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

name = 'SCIP_PY'

class pulp.apis.StringIO(initial_value='', newline='\n')

Bases: _TextIOBase

Text I/O implementation using an in-memory buffer.

The initial_value argument sets the value of object. The newline argument is like the one of TextIOWrapper’s constructor.

close()

Close the IO object.

Attempting any further operation after the object is closed will raise a ValueError.

This method has no effect if the file is already closed.

closed

getvalue()

Retrieve the entire contents of the object.

line_buffering

newlines

read(size=-1, /)

Read at most size characters, returned as a string.

If the argument is negative or omitted, read until EOF is reached. Return an empty string at EOF.

readable()

Returns True if the IO object can be read.

readline(size=-1, /)

Read until newline or EOF.

Returns an empty string if EOF is hit immediately.

seek(pos, whence=0, /)

Change stream position.

Seek to character offset pos relative to position indicated by whence:

0 Start of stream (the default). pos should be >= 0; 1 Current position - pos must be 0; 2 End of stream - pos must be 0.

Returns the new absolute position.

seekable()

Returns True if the IO object can be seeked.

tell()

Tell the current file position.

truncate(pos=None, /)

Truncate size to pos.

The pos argument defaults to the current file position, as returned by tell(). The current file position is unchanged. Returns the new absolute position.

writable()

Returns True if the IO object can be written.

write(s, /)

Write string to file.

Returns the number of characters written, which is always equal to the length of the string.

class pulp.apis.XPRESS(mip=True, msg=True, timeLimit=None, gapRel=None, options=None, keepFiles=False, path=None, heurFreq=None, heurStra=None, coverCuts=None, preSolve=None, warmStart=False)

Bases: LpSolver_CMD

The XPRESS LP solver that uses the XPRESS command line tool in a subprocess

Initializes the Xpress solver.

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• heurFreq – the frequency at which heuristics are used in the tree search

• heurStra – heuristic strategy

• coverCuts – the number of rounds of lifted cover inequalities at the top node

• preSolve – whether presolving should be performed before the main algorithm

• options – Adding more options, e.g. options = [“NODESELECTION=1”, “HEURDEPTH=5”] More about Xpress options and control parameters please see https://www.fico.com/fico-xpress-optimization/docs/latest/solver/optimizer/HTML/chapter7.html

• warmStart (bool) – if True, then use current variable values as start

actualSolve(lp)

Solve a well formulated lp problem

available()

True if the solver is available

defaultPath()

name = 'XPRESS'

static quote_path(path)

Quotes a path for the Xpress optimizer console, by wrapping it in double quotes and escaping the following characters, which would otherwise be interpreted by the Tcl shell: $ “ [

static readsol(filename, attrfile)

Read an XPRESS solution file

writeslxsol(name, *values)

Write a solution file in SLX format. The function can write multiple solutions to the same file, each solution must be passed as a list of (name,value) pairs. Solutions are written in the order specified and are given names “solutionN” where N is the index of the solution in the list.

Parameters:

• name (string) – file name

• values (list) – list of lists of (name,value) pairs

pulp.apis.XPRESS_CMD

alias of XPRESS

class pulp.apis.XPRESS_PY(mip=True, msg=True, timeLimit=None, gapRel=None, heurFreq=None, heurStra=None, coverCuts=None, preSolve=None, warmStart=None, export=None, options=None)

Bases: LpSolver

The XPRESS LP solver that uses XPRESS Python API

Initializes the Xpress solver.

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• timeLimit (float) – maximum time for solver (in seconds)

• gapRel (float) – relative gap tolerance for the solver to stop (in fraction)

• heurFreq – the frequency at which heuristics are used in the tree search

• heurStra – heuristic strategy

• coverCuts – the number of rounds of lifted cover inequalities at the top node

• preSolve – whether presolving should be performed before the main algorithm

• warmStart (bool) – if set then use current variable values as warm start

• export (string) – if set then the model will be exported to this file before solving

• options – Adding more options. This is a list the elements of which are either (name,value) pairs or strings “name=value”. More about Xpress options and control parameters please see https://www.fico.com/fico-xpress-optimization/docs/latest/solver/optimizer/HTML/chapter7.html

actualResolve(lp, prepare=None)

Resolve a problem that was previously solved by actualSolve().

actualSolve(lp, prepare=None)

Solve a well formulated lp problem

available()

True if the solver is available

buildSolverModel(lp)

Takes the pulp lp model and translates it into an xpress model

callSolver(lp, prepare=None)

Perform the actual solve from actualSolve() or actualResolve().

Parameters:

prepare – a function that is called with lp as argument and allows final tweaks to lp.solverModel before the low level solve is started.

findSolutionValues(lp)

getAttribute(lp, which)

Get an arbitrary attribute for the model that was previously solved using actualSolve().

name = 'XPRESS_PY'

class pulp.apis.YAPOSIB(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)

Bases: LpSolver

COIN OSI (via its python interface)

Copyright Christophe-Marie Duquesne 2012

The yaposib variables are available (after a solve) in var.solverVar The yaposib constraints are available in constraint.solverConstraint The Model is in prob.solverModel

Parameters:

• mip (bool) – if False, assume LP even if integer variables

• msg (bool) – if False, no log is shown

• options (list)

• timeLimit (float) – maximum time for solver (in seconds)

• args

• kwargs – optional named options to pass to each solver, e.g. gapRel=0.1, gapAbs=10, logPath=””,

actualSolve(lp, callback=None)

Solve a well formulated lp problem

available()

True if the solver is available

name = 'YAPOSIB'

pulp.apis.byref(C instance[, offset=0]) → byref-object

Return a pointer lookalike to a C instance, only usable as function argument

pulp.apis.clock()

monotonic() -> float

Monotonic clock, cannot go backward.

pulp.apis.configSolvers()

Configure the path the the solvers on the command line

Designed to configure the file locations of the solvers from the command line after installation

pulp.apis.coptstr(x)

pulp.apis.ctypesArrayFill(myList, type=<class 'ctypes.c_double'>)

Creates a c array with ctypes from a python list type is the type of the c array

pulp.apis.getSolver(solver, *args, **kwargs)

Instantiates a solver from its name

Parameters:

• solver (str) – solver name to create

• args – additional arguments to the solver

• kwargs – additional keyword arguments to the solver

Returns:

solver of type LpSolver

pulp.apis.getSolverFromDict(data)

Instantiates a solver from a dictionary with its data

Parameters:

data (dict) – a dictionary with, at least an “solver” key with the name of the solver to create

Returns:

a solver of type LpSolver

Raises:

PulpSolverError – if the dictionary does not have the “solver” key

Return type:

LpSolver

pulp.apis.getSolverFromJson(filename)

Instantiates a solver from a json file with its data

Parameters:

filename (str) – name of the json file to read

Returns:

a solver of type LpSolver

Return type:

LpSolver

pulp.apis.initialize(filename, operating_system='linux', arch='64')

reads the configuration file to initialise the module

pulp.apis.listSolvers(onlyAvailable=False)

List the names of all the existing solvers in PuLP

Parameters:

onlyAvailable (bool) – if True, only show the available solvers

Returns:

list of solver names

Return type:

list

pulp.apis.mktemp(suffix='', prefix='tmp', dir=None)

User-callable function to return a unique temporary file name. The file is not created.

Arguments are similar to mkstemp, except that the ‘text’ argument is not accepted, and suffix=None, prefix=None and bytes file names are not supported.

THIS FUNCTION IS UNSAFE AND SHOULD NOT BE USED. The file name may refer to a file that did not exist at some point, but by the time you get around to creating it, someone else may have beaten you to the punch.

class pulp.apis.redirect_stdout(new_target)

Bases: _RedirectStream

Context manager for temporarily redirecting stdout to another file.

# How to send help() to stderr with redirect_stdout(sys.stderr):

help(dir)

# How to write help() to a file with open(‘help.txt’, ‘w’) as f:

with redirect_stdout(f):

help(pow)

pulp.apis.setConfigInformation(**keywords)

set the data in the configuration file at the moment will only edit things in [locations] the keyword value pairs come from the keywords dictionary

pulp.apis.to_string(_obj)

pulp.apis.uuid4()

Generate a random UUID.