From 773196fb2fd2fbe3d6ca6856290a4e1161aeb7b2 Mon Sep 17 00:00:00 2001
From: MatteoRobbiati <robbiati.matteo@gmail.com>
Date: Mon, 27 Jan 2025 12:26:30 +0100
Subject: [PATCH] refactor: constructing an abstract QiboTN backend and adapt
 quimb and cutensornet

---
 src/qibotn/backends/cutensornet.py | 17 +++--------------
 src/qibotn/backends/quimb.py       | 16 +++-------------
 2 files changed, 6 insertions(+), 27 deletions(-)

diff --git a/src/qibotn/backends/cutensornet.py b/src/qibotn/backends/cutensornet.py
index 1d38520..d4f1bcc 100644
--- a/src/qibotn/backends/cutensornet.py
+++ b/src/qibotn/backends/cutensornet.py
@@ -1,12 +1,13 @@
 import numpy as np
-from qibo.backends.numpy import NumpyBackend
 from qibo.config import raise_error
 from qibo.result import QuantumState
 
+from qibotn.backends.abstract import QibotnBackend
+
 CUDA_TYPES = {}
 
 
-class CuTensorNet(NumpyBackend):  # pragma: no cover
+class CuTensorNet(QibotnBackend):  # pragma: no cover
     # CI does not test for GPU
     """Creates CuQuantum backend for QiboTN."""
 
@@ -77,22 +78,10 @@ class CuTensorNet(NumpyBackend):  # pragma: no cover
             ),
         }
 
-    def apply_gate(self, gate, state, nqubits):  # pragma: no cover
-        raise_error(NotImplementedError, "QiboTN cannot apply gates directly.")
-
-    def apply_gate_density_matrix(self, gate, state, nqubits):  # pragma: no cover
-        raise_error(NotImplementedError, "QiboTN cannot apply gates directly.")
-
-    def assign_measurements(self, measurement_map, circuit_result):
-        raise_error(NotImplementedError, "Not implemented in QiboTN.")
-
     def __del__(self):
         if hasattr(self, "cutn"):
             self.cutn.destroy(self.handle)
 
-    def set_precision(self, precision):
-        if precision != self.precision:
-            super().set_precision(precision)
 
     def cuda_type(self, dtype="complex64"):
         """Get CUDA Type.
diff --git a/src/qibotn/backends/quimb.py b/src/qibotn/backends/quimb.py
index df6488a..20223b3 100644
--- a/src/qibotn/backends/quimb.py
+++ b/src/qibotn/backends/quimb.py
@@ -2,8 +2,10 @@ from qibo.backends.numpy import NumpyBackend
 from qibo.config import raise_error
 from qibo.result import QuantumState
 
+from qibotn.backends.abstract import QibotnBackend
 
-class QuimbBackend(NumpyBackend):
+
+class QuimbBackend(QibotnBackend):
 
     def __init__(self, runcard):
         super().__init__()
@@ -36,18 +38,6 @@ class QuimbBackend(NumpyBackend):
         self.platform = "QuimbBackend"
         self.versions["quimb"] = self.quimb.__version__
 
-    def apply_gate(self, gate, state, nqubits):  # pragma: no cover
-        raise_error(NotImplementedError, "QiboTN cannot apply gates directly.")
-
-    def apply_gate_density_matrix(self, gate, state, nqubits):  # pragma: no cover
-        raise_error(NotImplementedError, "QiboTN cannot apply gates directly.")
-
-    def assign_measurements(self, measurement_map, circuit_result):
-        raise_error(NotImplementedError, "Not implemented in QiboTN.")
-
-    def set_precision(self, precision):
-        if precision != self.precision:
-            super().set_precision(precision)
 
     def execute_circuit(
         self, circuit, initial_state=None, nshots=None, return_array=False