8.3.2. 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("RowName", 'cons1')
cons1.get_str_attr("RowName")

# 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