dimod.AdjDictBQM.add_variable

AdjDictBQM.add_variable(v=None, bias=0.0)

Add a variable to the binary quadratic model.

Parameters:

• v (hashable, optional) – A label for the variable. Defaults to the length of the binary quadratic model, if that label is available. Otherwise defaults to the lowest available positive integer label.
• bias (numeric, optional, default=0) – The initial bias value for the added variable. If v is already a variable, then bias (if any) is adding to its existing linear bias.

Returns:

The label of the added variable.

Return type:

hashable

Raises:

TypeError – If the label is not hashable.

Examples

>>> bqm = dimod.AdjDictBQM('SPIN')
>>> bqm.add_variable()
0
>>> bqm.add_variable('a')
'a'
>>> bqm.add_variable()
2

>>> bqm = dimod.AdjDictBQM('SPIN')
>>> bqm.add_variable(1)
1
>>> bqm.add_variable()  # 1 is taken
0
>>> bqm.add_variable()
2