dimod.BinaryQuadraticModel.to_qubo

BinaryQuadraticModel.to_qubo()[source]

Convert a binary quadratic model to QUBO format.

If the binary quadratic model’s vartype is not Vartype.BINARY, values are converted.

Returns:2-tuple of form (biases, offset), where biases is a dict in which keys are pairs of variables and values are the associated linear or quadratic bias and offset is a number that represents the constant offset of the binary quadratic model.
Return type:tuple

Examples

This example converts a binary quadratic model with spin variables to QUBO format with binary variables.

>>> import dimod
>>> model = dimod.BinaryQuadraticModel({0: 1, 1: -1, 2: .5},
...                                    {(0, 1): .5, (1, 2): 1.5},
...                                    1.4,
...                                    dimod.SPIN)
>>> model.to_qubo()   # doctest: +SKIP
({(0, 0): 1.0, (0, 1): 2.0, (1, 1): -6.0, (1, 2): 6.0, (2, 2): -2.0}, 2.9)