feat: Circuits definition in python using magic methods on ModuloCircuitElement #359
Description
We want to do :
c = ModuloCircuit()
a = c.write_element(0)
b = c.write_element(1)
d = a + b # Instead of d = circuit.add(a, b)
circuit.compile_circuit()We can achieve it by adding the magic methods to the ModuloCircuitElement class and by adding the circuit they are tied to at initialization:
@dataclass(slots=True)
class ModuloCircuitElement:
"""
Represents an element within a modulo circuit with its associated offset.
Attributes:
emulated_felt (PyFelt): The emulated field element in the modulo circuit
offset (int): The offset in the values segment within the modulo circuit where the element is stored.
"""
emulated_felt: PyFelt
offset: int
circuit: ModuloCircuit
__repr__ = lambda self: f"ModuloCircuitElement({hex(self.value)}, {self.offset})"
@property
def value(self) -> int:
return self.emulated_felt.value
@property
def p(self) -> int:
return self.emulated_felt.p
@property
def felt(self) -> PyFelt:
return self.emulated_felt
def __add__(self, other: ModuloCircuitElement) -> ModuloCircuitElement:
return self.circuit.add(self, other)
def __neg__(self) -> ModuloCircuitElement:
return self.circuit.neg(self)
def __sub__(self, other: ModuloCircuitElement) -> ModuloCircuitElement:
return self.circuit.sub(self, other)
def __mul__(self, other: ModuloCircuitElement) -> ModuloCircuitElement:
return self.circuit.mul(self, other)
def __truediv__(self, other: ModuloCircuitElement) -> ModuloCircuitElement:
return self.circuit.div(self, other) And then changing associated methods in ModuloCircuit :
def write_element(
self,
elmt: PyFelt | int,
write_source: WriteOps = WriteOps.INPUT,
instruction: ModuloCircuitInstruction | None = None,
) -> ModuloCircuitElement:
"""
Register an emulated field element to the circuit given its value and the write source.
Returns a ModuloCircuitElement representing the written element with its offset as identifier.
"""
assert isinstance(elmt, PyFelt) or isinstance(
elmt, int
), f"Expected PyFelt or int, got {type(elmt)}"
if isinstance(elmt, int):
elmt = self.field(elmt)
value_offset = self.values_segment.write_to_segment(
ValueSegmentItem(
elmt,
write_source,
instruction,
)
)
res = ModuloCircuitElement(elmt, value_offset, circuit=self)
return resWe add self.uuid = uuid.uuid4() on the init method the ModuloCircuit, and then on the basic add sub mul div methods of ModuloCircuit, we add the check
assert a.circuit.uuid == b.circuit.uuid, "Cannot multiply elements from different circuits"However this leads to python cyclic imports and requires bigger refactor of the python package.