round for paulistring

Author: JulienCalistoTD

examples/scripts/google_execution_trials.py

@@ -56,5 +56,3 @@
 
 plot_results_sample_mode(results)
 plt.show()
-
-# %%

examples/scripts/observable_paulistring.py

@@ -23,7 +23,7 @@
 
 ps_obs = Observable(1 * I @ Z + 1 * I @ I)
 
-obs = ps_obs.to_matrix()
+obs = ps_obs.matrix
 
 print(obs)
 print(ps_obs)

mpqp/all.py

@@ -16,7 +16,7 @@
     submit,
 )
 from .execution.connection.qlm_connection import get_all_job_ids
-from .execution.devices import ATOSDevice, AWSDevice, IBMDevice
+from .execution.devices import ATOSDevice, AWSDevice, IBMDevice, GOOGLEDevice
 from .execution.vqa import Optimizer, minimize
 from .gates import (
     CNOT,

mpqp/core/instruction/measurement/pauli_string.py

@@ -63,7 +63,7 @@ def nb_qubits(self) -> int:
         return 0 if len(self._monomials) == 0 else self._monomials[0].nb_qubits
 
     def __str__(self):
-        return " + ".join(map(str, self._monomials))
+        return " + ".join(map(str, self.round().monomials))
 
     def __repr__(self):
         return str(self)
@@ -165,6 +165,32 @@ def simplify(self) -> PauliString:
                 PauliStringMonomial(0, [I for _ in range(self.nb_qubits)])
             )
         return res
+    
+    def round(self, round_off_till: int = 5) -> PauliString:
+        """Round the coefficients of the PauliString to a specified number of decimal places.
+
+        Example:
+            >>> ps = 0.6875*I@I + 0.415*I@X + 0.1275*I@Z + 1.0*X@I + 1.0*X@X + 0.0375*Z@I + 0.085*Z@X + -0.2225*Z@Z
+            >>> rounded_ps = ps.round(1)
+            >>> print(rounded_ps)
+            -0.2*Z@Z + 1.0*X@X + 0.1*I@Z + 1.0*X@I + 0.1*Z@X + 0.7*I@I + 0.4*I@X
+
+        Args:
+            round_off_till : Number of decimal places to round the coefficients to. Defaults to 5.
+
+        Returns:
+            PauliString: A PauliString with coefficients rounded to the specified number of decimal places.
+        """
+        res = PauliString()
+        for mono in self.monomials:
+            coef = float(round(mono.coef, round_off_till))
+            if coef != 0:
+                res.monomials.append(PauliStringMonomial(coef, mono.atoms))
+            if len(res.monomials) == 0:
+                res.monomials.append(
+                    PauliStringMonomial(0, [I for _ in range(self.nb_qubits)])
+            )
+        return res
 
     def to_matrix(self) -> Matrix:
         """Convert the PauliString to a matrix representation.

mpqp/execution/providers/google.py

@@ -17,12 +17,10 @@
 from cirq.sim.state_vector_simulator import StateVectorTrialResult
 from cirq.transformers.optimize_for_target_gateset import optimize_for_target_gateset
 from cirq.value.probability import state_vector_to_probabilities
-from cirq.transformers.routing.route_circuit_cqc import RouteCQC
 from cirq.sim.sparse_simulator import Simulator
 from cirq.circuits.circuit import Circuit as Cirq_circuit
 from cirq.study.result import Result as cirq_result
 from cirq.ops.linear_combinations import PauliSum as Cirq_PauliSum
-from cirq.transformers.target_gatesets.sqrt_iswap_gateset import SqrtIswapTargetGateset
 from cirq_google.engine.virtual_engine_factory import (
     load_median_device_calibration,
     create_device_from_processor_id,

mpqp/tools/visualization.py

@@ -54,7 +54,7 @@ def _prep_plot(result: Result):
     plt.xlabel("State")
     plt.ylabel("Counts")
     device = result.job.device
-    plt.title(type(device).__name__ + ", " + device.name)
+    plt.title(type(device).__name__ + "\n" + device.name)
 
 
 @typechecked