Invalid circuit splitting for Badger

[lmondada]

The following code panics with the error "all nodes must have dataflow signature". This test can be run on the bug/invalid-circ-split branch in the file tket2/tests/badger.rs.

use std::num::NonZeroUsize;

use rstest::{fixture, rstest};
use tket2::optimiser::badger::BadgerOptions;
use tket2::optimiser::{BadgerOptimiser, DefaultBadgerOptimiser};
use tket2::serialize::TKETDecode;
use tket2::Circuit;
use tket_json_rs::circuit_json::SerialCircuit;

/// A set of equivalence circuit classes (ECC)
///
/// This is the complete set of ECCs for 2-qubit circuits with up to
/// 4 gates, using the NAM gateset (CX, Rz, H).
#[fixture]
fn nam_4_2() -> DefaultBadgerOptimiser {
    BadgerOptimiser::default_with_eccs_json_file("../test_files/Nam_4_2_complete_ECC_set.json")
        .unwrap()
}

#[fixture]
fn barenco_tof_10() -> Circuit {
    let json = std::fs::read_to_string("../test_files/barenco_tof_10.json").unwrap();
    let ser: SerialCircuit = serde_json::from_str(&json).unwrap();
    ser.decode().unwrap()
}

#[rstest]
fn badger_barenco_tof_10(barenco_tof_10: Circuit, nam_4_2: DefaultBadgerOptimiser) {
    let opt_circ = nam_4_2.optimise(
        &barenco_tof_10,
        BadgerOptions {
            max_circuit_cnt: Some(0), // This will abort the optimisation immediately
            n_threads: NonZeroUsize::new(2).unwrap(),
            split_circuit: true,
            ..Default::default()
        },
    );
    assert_eq!(opt_circ, barenco_tof_10);
}

[lmondada]

Was introduced by #493

[lmondada]

Here's an MWE, using a single Rz rotation. Could it be an issue with handling gates with float inputs? I've pushed this example to the branch bug/invalid-circ-split, with a new test case in the tket2/src/passes/chunks.rs file.

    /// Just a one-qubit circuit with Rz gate
    #[fixture]
    fn rz() -> Circuit {
        let json = r#"{"phase":"0.0","commands":[{"op":{"type":"Rz","n_qb":1,"params":["0.25"],"signature":["Q"]},"args":[["q",[0]]]}],"qubits":[["q",[1]],["q",[0]]],"bits":[],"implicit_permutation":[[["q",[0]],["q",[0]]],[["q",[1]],["q",[1]]]]}"#;
        let ser: SerialCircuit = serde_json::from_str(json).unwrap();
        ser.decode().unwrap()
    }

    #[rstest]
    fn split_rz(rz: Circuit) {
        let chunks = CircuitChunks::split_with_cost(&rz, 1, |_| 0);
        assert_eq!(chunks.len(), 1);
    }

[aborgna-q]

This should get fixed with the upcoming hugr 0.10 release. #508

[aborgna-q]

This seems to be fixed now, but the original badger_barenco_tof_10 test still fails due to the circuits not matching after the badger run (some rewrites may be applied before the timeout is triggered?)