Quantum Program Constraints

When synthesizing a quantum program, you can pass in constraints to the generation; for example, requiring that no more than 53 qubits are used. The Classiq engine allows the following constraints, each of which can pass to the synthesis engine:

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

Pass constraints as follows:

SDKTextual Model

from classiq import Model, synthesize, set_constraints
from classiq.model import Constraints, TranspilerBasisGates

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

Alternatively, you can pass the constraints in the constraints argument of the synthesize method, or change it via a property setter:

from classiq import Model, synthesize
from classiq.model import Constraints, TranspilerBasisGates

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

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

Optimization Parameter

When synthesizing a quantum program, to optimize the quantum program 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 quantum program, setting it instead as the optimization parameter.

SDKTextual Model

from classiq import Model, set_constraints, synthesize
from classiq.model import Constraints, TranspilerBasisGates, OptimizationParameter

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

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