8.6.16. Column¶

class Column¶

Column contains the coefficient information of a variable in existing constraints. When adding a variable, A column can be provided to initialize the coefficients of the variable in existing constraints. For example:

col = Column(model.getConstrs(), coeffs)
v = model.addVar(column = col)

Methods

`__init__()`	Construct a Column
`addTerms()`	Add one or more term(s)
`clear()`	Clear all included terms
`copy()`	Return a copy of a Column
`getCoeff()`	Obtain the coefficient of a term in a Column
`getConstr()`	Get the constraint of a term in a Column
`remove()`	Delete some terms contained in Column
`size()`	Obtain the number of terms

__init__(coeffs=None, constrs=None)¶

Construct a Column

Parameters

coeffs=None – The initial coefficient of the Column, which can be a number or an array.
constrs=None – The initial constraint of a Column, which can be a constraint or an array.

example:

Column(1, c0)
Column([1, 2, 3], [c0, c1, c2])

addTerms(coeffs, constrs)¶

Add one or more term(s)

Parameters

coeffs – The coefficient of the term(s) to be added, which can be a number or an array.
constrs – The constraint of the term(s) to be added, which can be a single constraint or an array.

example:

column.addTerms([1, 2], [c0, c1])
column.addTerms(1, c0)

clear()¶

Clear all included terms

example:

column = Column([1, 2], [c0, c1])
column.clear()
print(column.size() == 0)

copy()¶

Return a copy of a Column.

example:

another = column.copy()

getCoeff(index)¶

Obtain the coefficient of a term in a Column.

Parameters: index – The index of the term to obtain the coefficient.

example:

column = Column([1, 2], [c0, c1])
print(column.getCoeff(1) == 2.0)

getConstr(index)¶

Get the constraint of a term in a Column.

Parameters: index – The index of the term to obtain the constraint.

example:

column = Column([1, 2], [c0, c1])
print(column.getConstr(1).sameAs(c1))

remove(item)¶

Delete some terms contained in Column

Parameters: item – If item is a number, the term whose index is item is deleted. If the item is a constraint, all terms that contain the constraint are deleted.

example:

column = Column([1, 2], [c0, c1])
column.remove(0)
column.remove(c1)
print(column.size() == 0)

size()¶

Obtain the number of terms.

example:

column = Column([1, 2], [c0, c1])
print(column.size() == 2)