From cb5732c43cff98a42b407919bd5e7c8950a24732 Mon Sep 17 00:00:00 2001
From: Callum Macpherson <93673602+CalMacCQ@users.noreply.github.com>
Date: Sat, 12 Oct 2024 14:55:11 +0100
Subject: [PATCH] fix: failing resynth test case  (#10)

* add test case back in

* fix cnot synthesis

* remove import
---
 src/topt_proto/clifford.py |  9 +++------
 tests/qasm/cnot_t_4.qasm   | 13 +++++++++++++
 2 files changed, 16 insertions(+), 6 deletions(-)
 create mode 100644 tests/qasm/cnot_t_4.qasm

diff --git a/src/topt_proto/clifford.py b/src/topt_proto/clifford.py
index 4391e1d..c1e61da 100644
--- a/src/topt_proto/clifford.py
+++ b/src/topt_proto/clifford.py
@@ -32,11 +32,8 @@ def pauli_tensor_to_circuit(pauli_tensor: QubitPauliTensor) -> Circuit:
 def get_cnot_circuit(pbox: PhasePolyBox) -> Circuit:
     """Generate a CNOT circuit implementing the linear reversible circuit L."""
     # cheat by synthesising the CNOT circuit with qiskit and converting
-    qc = synth_cnot_count_full_pmh(
-        pbox.linear_transformation, section_size=2
-    )  # correct for endianness
-    qc2 = qc.reverse_bits()
-    tkc_cnot: Circuit = qiskit_to_tk(qc2)
+    qc = synth_cnot_count_full_pmh(pbox.linear_transformation, section_size=2)
+    tkc_cnot: Circuit = qiskit_to_tk(qc)
     return tkc_cnot
 
 
@@ -46,7 +43,7 @@ def get_pauli_conjugate(
 ) -> QubitPauliTensor:
     """Given a PhasePolyBox (U) and a QubitPauliTensor (P), returns P' = L P L†."""
 
-    l_cnot_circuit: Circuit = get_cnot_circuit(pbox=pbox)
+    l_cnot_circuit: Circuit = get_cnot_circuit(pbox=pbox).dagger()
 
     # Get L as a Tableau
     l_tableau = UnitaryTableau(l_cnot_circuit)
diff --git a/tests/qasm/cnot_t_4.qasm b/tests/qasm/cnot_t_4.qasm
new file mode 100644
index 0000000..98883be
--- /dev/null
+++ b/tests/qasm/cnot_t_4.qasm
@@ -0,0 +1,13 @@
+OPENQASM 2.0;
+include "qelib1.inc";
+
+qreg q[3];
+cx q[2],q[0];
+rz(0.25*pi) q[0];
+cx q[1],q[0];
+cx q[2],q[0];
+rz(0.25*pi) q[0];
+cx q[1],q[0];
+cx q[0],q[1];
+cx q[1],q[0];
+rz(0.25*pi) q[1];
\ No newline at end of file