7.3.2. MdoCons

class mindoptpy.MdoCons(model, index: int)

Bases: object

This object implements the data structure to hold an optimization constraint. An empty variaconstraintble object can be created by calling mindoptpy.MdoModel.add_cons(). Once created, users may modify the its left-hand-side value or right-hand-side value by calling mindoptpy.MdoCons.set_real_attr() with a proper real-valued model attribute.

Examples

from mindoptpy import *

# Create an empty model.
model = MdoModel()
MDO_INFINITY = MdoModel.get_infinity()

# Add variables.
x1 = model.add_var(0, MDO_INFINITY, 1, None, "x1", False)
x2 = model.add_var(0, MDO_INFINITY, 1, None, "x2", False)
x3 = model.add_var(0, 3, 1, None, "x2", False)

# Add constraints
cons1 = model.add_cons(2 * x1 - x2 <= 3, "c1")
cons2 = model.add_cons(3 * x1 + 2 * x2 <= 5, "c2")

# Set/get constraint attributes
cons1.set_real_attr("RHS", 3.5)
cons1.get_real_attr("RHS")
cons1.set_str_attr("ColName", 'cons1')
cons1.get_str_attr("ColName")

# Check constraint
cons1.same_as(model.get_cons(0))

Methods

get_index()

Function to retrieve the current index of the constraint in the optimization model.

get_int_attr()

Function to retrieve the value of an integer-valued row attribute.

get_real_attr()

Function to retrieve the value of a real-valued row attribute.

get_str_attr()

Function to retrieve the value of a string-valued row attribute.

same_as()

Check whether two constraint objects refer to the same constraint.

set_int_attr()

Function to change the value of an integer-valued row attribute.

set_real_attr()

Function to change the value of a real-valued row attribute.

set_str_attr()

Function to change the value of a string-valued row attribute.

get_index()

This function retrieves the current index of the constraint in the optimization model.

Returns

The current index of the constraint.

Return type

int

get_int_attr(att: str)

This function retrieves the value of an integer-valued row attribute.

Parameters

att (str) – An integer-valued row attribute to access.

Returns

The current value of the integer-valued row attribute.

Return type

int

get_real_attr(att: str)

This function retrieves the value of a real-valued row attribute.

Parameters

att (str) – A real-valued row attribute to access.

Returns

The current value of the real-valued row attribute.

Return type

float

get_str_attr(att: str)

This function retrieves the value of a string-valued row attribute.

Parameters

att (str) – A string-valued row attribute to access.

Returns

The current value of the string-valued row attribute.

Return type

str

same_as(rhs)

Check whether two constraint objects refer to the same constraint.

Parameters

rhs (MdoCons) – Another constraint object.

Returns

A boolean flag indicates if two constraint objects refer to the same constraint.

Return type

bint

set_int_attr(att: str, val: int)

This function changes the value of an integer-valued row attribute.

Parameters

att (str) – An integer-valued row attribute to access.

Return val

A new value for the integer-valued row attribute.

Return type

int

set_real_attr(att: str, val: float)

This function changes the value of a real-valued row attribute.

Parameters

att (str) – A real-valued row attribute to access.

Return val

A new value for the real-valued row attribute.

Return type

float

set_str_attr(att: str, val: str)

This function changes the value of a string-valued row attribute.

Parameters

att (str) – A string-valued row attribute to access.

Return val

A new value for the string-valued row attribute.

Return type

str