8.7.4. tupledict

class tupledict

A dictionary with tuples as keys. This data structure allows you to index multiple variables using tuple keys. You can call tupledict.sum and tupledict.prod to quickly generate linear expressions by specifying query criteria. tupledict objects are generally returned by Model.addVars . Note that the tupledict returned by Model.addConstrs is composed of constraints rather than variables.

Methods

__init__()

Construct a tupledict

clean()

Clear the index to release memory

prod()

Specify a row vector and a query to produce a column vector, then return the product of the two vectors

select()

Query the tupledict to obtain the matching value list

sum()

Query a list from tupledict, and sum them as an expression
__init__(*args, **kwargs)

Construct a tupledict.

Parameters

  • *args –

    Array parameters.

  • **kwargs –

    Dictionary parameters.

example:

tupledict()
tupledict(another_dict)
tupledict([('a', 1), (' B ', 2)])
tupledict(a = 1, B = 2)
clean()

Clear the index to release memory.

Note

After the index is cleared, it will be rebuilt before a query is performed again.

prod(coeffs, *query=[])

Specify a row vector and a query to produce a column vector, then return the product of the two vectors. The product is an expression.

Parameters

  • coeffs – Row vector.

  • *query=[] –

    The pattern of the key to be matched. The matching result is used as the column vector.

example:

m = Model()
x = m.addVars([(1,1), (1,2), (1,3)])
coeff = dict([((1,1), 1), ((1,2), 2), ((1,3), 3)])
expr = x.prod(coeff)
expr = x.prod(coeff, '*', 3)
select(*query)

Query the tupledict to obtain the matching value list.

Parameters

*query –

The pattern of the key to be matched.

example:

li = tupledict([((1, 2), 3), ((2, 2), 4)])
li.select(1)
li.select('*', 2)

Note

Calling select triggers the creation of index, but modifying the tupledict clears the index. Avoid frequent index creation.

sum(*query=[])

Query a list from tupledict, and sum them as an expression.

Parameters

*query=[] –

The pattern of the key to be matched.

example:

m = Model()
x = m.addVar()
y = m.addVar()
mapping1 = ((1, 2), 1 * x + 2 * y)
mapping2 = ((2, 1), 2 * x + 1 * y)
td = tupledict([mapping1, mapping2])
linExpr = td.sum('*')