🐛 Remove side effect in focus_gflow func

[nabe98]

• Fix bug in focus_gflow
• Enable CI on every PR

[masa10-f]

@nabe98 Did you check this change fixes the side effect on your program?

[nabe98]

@masa10-f
Yes. I used the following codes to check the side effect.

# %%
import numpy as np

from graphix_zx.circuit import MBQCCircuit, circuit2graph
from graphix_zx.zxgraphstate import ZXGraphState
from graphix_zx.focus_flow import focus_gflow, is_focused


def random_gflow_circ(
    width: int,
    depth: int,
    rng: np.random.Generator = np.random.default_rng(),
    edge_p: float = 0.5,
) -> MBQCCircuit:
    """Generate a random MBQC circuit which has gflow

    Parameters
    ----------
    width : int
        circuit width
    depth : int
        circuit depth
    rng : np.random.Generator, optional
        random number generator, by default np.random.default_rng()
    edge_p : float, optional
        probability of adding CZ gate, by default 0.5

    Returns
    -------
    MBQCCircuit
        generated MBQC circuit
    """
    angle_list = [0, np.pi / 3, 2 * np.pi / 3, np.pi]
    circ = MBQCCircuit(width)
    for d in range(depth):
        for j in range(width):
            circ.j(j, rng.choice(angle_list))
        if d < depth - 1:
            for j in range(width):
                if rng.random() < edge_p:
                    circ.cz(j, (j + 1) % width)
            num = rng.integers(0, width)
            if num > 0:
                target = set(rng.choice([i for i in range(width)], num))
                circ.phase_gadget(target, rng.choice(angle_list))

    return circ

circ = random_gflow_circ(4, 4)
graph, flow = circuit2graph(circ)
print(flow)

zxgraph = ZXGraphState()
zxgraph.append(graph)
flow_opt = focus_gflow(flow, zxgraph)
print(flow)

print(is_focused(flow, graph))
print(is_focused(flow_opt, graph))
print("flow == flow_opt: ", flow == flow_opt)
# %%

In the previous implementation, flow == flow_opt evaluated to True, but with this modification, it now returns False. Additionally, I confirmed that flow remains unaffected (in two print(flow) lines).

[masa10-f]

Sure! You can merge!