Class PWLConstraintInterface

Creates a new PWLConstraintInterface.

The PWL constraint interface is exposed by the top-level Cplex class as Cplex.pwl_constraints. This constructor is not meant to be used externally.

Overrides: _baseinterface.BaseInterface.__init__

Returns the number of PWL constraints in the problem.

Example usage:

>>> import cplex
>>> c = cplex.Cplex()
>>> c.pwl_constraints.get_num()
0
>>> indices = c.variables.add(names=['y', 'x'])
>>> idx = c.pwl_constraints.add(vary='y', varx='x',
...                             preslope=0.5, postslope=2.0,
...                             breakx=[0.0, 1.0, 2.0],
...                             breaky=[0.0, 1.0, 4.0],
...                             name='pwl1')
>>> c.pwl_constraints.get_num()
1

Adds a PWL constraint to the problem.

vary: the index of the 'y' variable in the vary=pwl(varx) function.

varx: the index of the 'x' variable in the vary=pwl(varx) function.

preslope: before the first segment of the PWL function there is a half-line; its slope is specified by preslope.

postslope: after the last segment of the the PWL function there is a half-line; its slope is specified by postslope.

breakx: A list containing the indices of the 'x' variables involved.

breaky: A list containing the indices of the 'y' variables involved.

name: the name of the PWL constraint; defaults to the empty string.

Returns the index of the PWL constraint.

Example usage:

>>> import cplex
>>> c = cplex.Cplex()
>>> indices = c.variables.add(names=['y', 'x'])
>>> idx = c.pwl_constraints.add(vary='y', varx='x',
...                             preslope=0.5, postslope=2.0,
...                             breakx=[0.0, 1.0, 2.0],
...                             breaky=[0.0, 1.0, 4.0],
...                             name='pwl1')
>>> c.pwl_constraints.get_num()
1

Deletes PWL constraints from the problem.

There are four forms by which pwl_constraints.delete may be called.

pwl_constraints.delete()

deletes all PWL constraints from the problem.

pwl_constraints.delete(i)

i must be a PWL constraint name or index. Deletes the PWL constraint whose index or name is i.

pwl_constraints.delete(seq)

seq must be a sequence of PWL constraint names or indices. Deletes the PWL constraints with names or indices contained within s. Equivalent to [pwl_constraints.delete(i) for i in s].

pwl_constraints.delete(begin, end)

begin and end must be PWL constraint indices or PWL constraint names. Deletes the PWL constraints with indices between begin and end, inclusive of end. Equivalent to pwl_constraints.delete(range(begin, end + 1)). This will give the best performance when deleting batches of PWL constraints.

See CPXdelpwl in the Callable Library Reference Manual for more detail.

Example usage:

>>> import cplex
>>> c = cplex.Cplex()
>>> indices = c.variables.add(names=['y', 'x'])
>>> idx = c.pwl_constraints.add(vary='y', varx='x',
...                             preslope=0.5, postslope=2.0,
...                             breakx=[0.0, 1.0, 2.0],
...                             breaky=[0.0, 1.0, 4.0],
...                             name='pwl1')
>>> c.pwl_constraints.get_num()
1
>>> c.pwl_constraints.delete(idx)
>>> c.pwl_constraints.get_num()
0

Returns the names of a set of PWL constraints.

May be called by four forms.

pwl_constraints.get_names()

return the names of all PWL constraints in the problem.

pwl_constraints.get_names(i)

i must be a PWL constraint name or index. Returns the name of PWL constraint i.

pwl_constraints.get_names(seq)

seq must be a sequence of PWL constraint names or indices. Returns the names of PWL constraints with names or indices in s. Equivalent to [pwl_constraints.get_names(i) for i in s]

pwl_constraints.get_names(begin, end)

begin and end must be PWL constraint indices or PWL constraint names. Returns the names of PWL constraints with indices between begin and end, inclusive of end. Equivalent to pwl_constraints.get_names(range(begin, end + 1))

Example usage:

>>> import cplex
>>> c = cplex.Cplex()
>>> indices = c.variables.add(names=['y', 'x'])
>>> idx = c.pwl_constraints.add(vary='y', varx='x',
...                             preslope=0.5, postslope=2.0,
...                             breakx=[0.0, 1.0, 2.0],
...                             breaky=[0.0, 1.0, 4.0],
...                             name='pwl1')
>>> c.pwl_constraints.get_names(idx)
'pwl1'

Returns the definitions of a set of PWL constraints.

Returns a list of PWL definitions, where each definition is a list containing the following components: vary, varx, preslope, postslope, breakx, breaky (see add).

May be called by four forms.

pwl_constraints.get_definitions()

return the definitions of all PWL constraints in the problem.

pwl_constraints.get_definitions(i)

i must be a PWL constraint name or index. Returns the definition of PWL constraint i.

pwl_constraints.get_definitions(seq)

seq must be a sequence of PWL constraint names or indices. Returns the definitions of PWL constraints with names or indices in s. Equivalent to [pwl_constraints.get_definitions(i) for i in s]

pwl_constraints.get_definitions(begin, end)

begin and end must be PWL constraint indices or PWL constraint names. Returns the definitions of PWL constraints with indices between begin and end, inclusive of end. Equivalent to pwl_constraints.get_definitions(list(range(begin, end + 1)))

Example usage:

>>> import cplex
>>> c = cplex.Cplex()
>>> indices = c.variables.add(names=['y', 'x'])
>>> idx = c.pwl_constraints.add(vary='y', varx='x',
...                             preslope=0.5, postslope=2.0,
...                             breakx=[0.0, 1.0, 2.0],
...                             breaky=[0.0, 1.0, 4.0],
...                             name='pwl1')
>>> c.pwl_constraints.get_definitions(idx)
[0, 1, 0.5, 2.0, [0.0, 1.0, 2.0], [0.0, 1.0, 4.0]]