dwave.optimization.model.Symbol.iter_predecessors

Symbol.iter_predecessors()

Iterate over a node’s predecessors in the model.

Examples

This example constructs a \(b = \sum a\) model, where \(a\) is a multiplication of two symbols, and iterates over the predecessor’s of \(b\) (which is just \(a\)).

>>> from dwave.optimization.model import Model
>>> model = Model()
>>> i = model.integer((2, 2), upper_bound=20)
>>> c = model.constant([[21, 11], [10, 4]])
>>> a = c * i
>>> b = a.sum()
>>> a.equals(next(b.iter_predecessors()))
True