add atol parameter to SparsePauliOp.equiv

qiskit/quantum_info/operators/symplectic/sparse_pauli_op.py

@@ -15,7 +15,7 @@
 
 from collections import defaultdict
 from numbers import Number
-from typing import Dict
+from typing import Dict, Optional
 
 import numpy as np
 import retworkx as rx
@@ -139,18 +139,21 @@ def __eq__(self, other):
             and self.paulis == other.paulis
         )
 
-    def equiv(self, other):
+    def equiv(self, other, atol: Optional[float] = None):
         """Check if two SparsePauliOp operators are equivalent.
 
         Args:
             other (SparsePauliOp): an operator object.
+            atol: Absolute numerical tolerance for checking equivalence.
 
         Returns:
             bool: True if the operator is equivalent to ``self``.
         """
         if not super().__eq__(other):
             return False
-        return np.allclose((self - other).simplify().coeffs, [0])
+        if atol is None:
+            atol = self.atol
+        return np.allclose((self - other).simplify().coeffs, 0.0, atol=atol)
 
     @property
     def settings(self) -> Dict:

releasenotes/notes/sparse-pauli-equiv-atol-58f5dfe7f39b70ee.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    Adds `atol` parameter to :meth:`.SparsePauliOp.equiv`.

test/python/quantum_info/operators/symplectic/test_sparse_pauli_op.py

@@ -592,6 +592,13 @@ def test_equiv(self, num_qubits):
         if not spp_op2.equiv(zero):
             self.assertFalse(spp_op2.equiv(spp_op2 + spp_op2))
 
+    def test_equiv_atol(self):
+        """Test equiv method with atol."""
+        op1 = SparsePauliOp.from_list([("X", 1), ("Y", 2)])
+        op2 = op1 + 1e-7 * SparsePauliOp.from_list([("I", 1)])
+        self.assertFalse(op1.equiv(op2))
+        self.assertTrue(op1.equiv(op2, atol=1e-7))
+
     def test_eq_equiv(self):
         """Test __eq__ and equiv methods with some specific cases."""
         with self.subTest("shuffled"):