feat: abstract qibotn backend

src/qibotn/backends/abstract.py

@@ -0,0 +1,41 @@
+from abc import abstractmethod
+from qibo.backends.numpy import NumpyBackend
+from qibo.config import raise_error
+
+
+DEFAULT_CONFIGURATION = {
+    "MPI_enabled": False,   # TODO: cutensornet specific, TBRemoved 
+    "NCCL_enabled": False,  # TODO: cutensornet specific, TBRemoved 
+    "expectation_enabled": False,
+    "pauli_string_pattern": None,
+    "MPS_enabled": False,
+    "gate_algo": None,
+    "mps_opts": None,
+}
+
+
+
+class QibotnBackend(NumpyBackend):
+
+    def __init__(self, runcard:dict = DEFAULT_CONFIGURATION):
+        super().__init__()
+
+    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)
+    
+    @abstractmethod
+    def configure_tn_simulation(self, **config):
+        """Configure the TN simulation that will be performed."""
+        pass
+
+