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README
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# Copyright J.S. Roy ([email protected]), 2003-2005
# Copyright Stuart A. Mitchell ([email protected])
# See the LICENSE file for copyright information.
PuLP is an LP modeler written in python. PuLP can generate MPS or LP files
and call GLPK[1], COIN CLP/CBC[2], CPLEX[3], and GUROBI[4] to solve linear
problems.
See the examples directory for examples.
PuLP requires Python >= 2.5.
The examples require at least a solver in your PATH or a shared library file.
Documentation is found on https://www.coin-or.org/PuLP/.
A comprehensive wiki can be found at https://www.coin-or.org/PuLP/
Use LpVariable() to create new variables. To create a variable 0 <= x <= 3
>>> x = LpVariable("x", 0, 3)
To create a variable 0 <= y <= 1
>>> y = LpVariable("y", 0, 1)
Use LpProblem() to create new problems. Create "myProblem"
>>> prob = LpProblem("myProblem", LpMinimize)
Combine variables to create expressions and constraints and add them to the
problem.
>>> prob += x + y <= 2
If you add an expression (not a constraint), it will
become the objective.
>>> prob += -4*x + y
Choose a solver and solve the problem. ex:
>>> status = prob.solve(GLPK(msg = 0))
Display the status of the solution
>>> LpStatus[status]
'Optimal'
You can get the value of the variables using value(). ex:
>>> value(x)
2.0
Exported Classes:
- LpProblem -- Container class for a Linear programming problem
- LpVariable -- Variables that are added to constraints in the LP
- LpConstraint -- A constraint of the general form
a1x1+a2x2 ...anxn (<=, =, >=) b
- LpConstraintVar -- Used to construct a column of the model in column-wise
modelling
Exported Functions:
- value() -- Finds the value of a variable or expression
- lpSum() -- given a list of the form [a1*x1, a2x2, ..., anxn] will construct
a linear expression to be used as a constraint or variable
- lpDot() --given two lists of the form [a1, a2, ..., an] and
[ x1, x2, ..., xn] will construct a linear epression to be used
as a constraint or variable
Comments, bug reports, patches and suggestions are welcome.
References:
[1] http://www.gnu.org/software/glpk/glpk.html
[2] http://www.coin-or.org/
[3] http://www.cplex.com/
[4] http://www.gurobi.com/