Circuit Constraints

When synthesizing a circuit, you can pass in constraints to the generation; for example, requiring that no more than 53 qubits will be used. Classiq allows the following constraints, each of which can pass to the circuit generator:

• Depth: the maximum depth of the circuit
• Width: the maximum amount of qubits in the circuit
• Gate count: the maximum number of times a gate appears

Pass constraints as follows:

SDKTextual Model

from classiq import Model
from classiq.model import Constraints, TranspilerBasisGates
from classiq.builtin_functions.range_types import NonNegativeIntRange

constraints = Constraints(
    max_width=20,
    max_depth=100,
    max_gate_count={
        TranspilerBasisGates.CX: 10,
        TranspilerBasisGates.T: 20,
    },
)
model = Model(constraints=constraints)
model.synthesize()

Alternatively, you can pass the constraints in the constraints argument of the synthesize method.

{
    "constraints": {
        "max_width": 20,
        "max_depth": 100,
        "max_gate_count": {
            "CX": 10,
            "T": 20
        }
    },
    "logic_flow": []
}

Optimization Parameter

When synthesizing a circuit, to optimize the circuit according to a parameter, set the optimization_parameter field. The possible parameters are the same parameters that can be constrained.

The following example shows how to remove the width constraint in the circuit, setting it instead as the optimization parameter.

SDKTextual Model

from classiq import Model
from classiq.model import Constraints, TranspilerBasisGates, OptimizationParameter
from classiq.builtin_functions.range_types import NonNegativeIntRange

constraints = Constraints(
    max_depth=100,
    max_gate_count={
        TranspilerBasisGates.CX: 10,
        TranspilerBasisGates.T: 20,
    },
    optimization_parameter=OptimizationParameter.WIDTH,
)
model = Model()
model.synthesize(constraints=constraints)

{
    "constraints": {
        "max_depth": 20,
        "max_gate_count": {
            "CX": 10,
            "T": 20
        },
        "optimization_parameter": "width"
    },
    "logic_flow": []
}