Add algorithmic errors tracking to qml.Tracker (#5465)

**Context:** Update `qml.Tracker` to track and combine error

**Description of the Change:** Add algorithmic error tracking in the
`simulator_tracking` device modifier.

**Benefits:** `tracker` will track algorithmic errors. 

**Possible Drawbacks:** N/A

**Related GitHub Issues:** N/A

---------

Co-authored-by: Jay Soni <jbsoni@uwaterloo.ca>

doc/releases/changelog-dev.md

@@ -209,6 +209,10 @@
  [stim](https://github.com/quantumlib/Stim) `v1.13.0`.
  [(#5409)](https://github.com/PennyLaneAI/pennylane/pull/5409)
 
+* `qml.specs` and `qml.Tracker` now return information about algorithmic errors for the qnode as well.
+ [(#5464)](https://github.com/PennyLaneAI/pennylane/pull/5464)
+ [(#5465)](https://github.com/PennyLaneAI/pennylane/pull/5465)
+
 * `qml.specs` now returns information regarding algorithmic errors for the qnode as well.
  [(#5464)](https://github.com/PennyLaneAI/pennylane/pull/5464)
 

pennylane/devices/modifiers/simulator_tracking.py

@@ -46,13 +46,15 @@ def execute(self, circuits, execution_config=DefaultExecutionConfig):
  results=r,
  shots=shots,
  resources=c.specs["resources"],
+ errors=c.specs["errors"],
  )
  else:
  self.tracker.update(
  simulations=1,
  executions=qpu_executions,
  results=r,
  resources=c.specs["resources"],
+ errors=c.specs["errors"],
  )
  self.tracker.record()
  return results
@@ -85,7 +87,7 @@ def execute_and_compute_derivatives(self, circuits, execution_config=DefaultExec
  if self.tracker.active:
  batch = (circuits,) if isinstance(circuits, QuantumScript) else circuits
  for c in batch:
- self.tracker.update(resources=c.specs["resources"])
+ self.tracker.update(resources=c.specs["resources"], errors=c.specs["errors"])
  self.tracker.update(
  execute_and_derivative_batches=1,
  executions=len(batch),
@@ -119,7 +121,7 @@ def execute_and_compute_jvp(self, circuits, tangents, execution_config=DefaultEx
  if self.tracker.active:
  batch = (circuits,) if isinstance(circuits, QuantumScript) else circuits
  for c in batch:
- self.tracker.update(resources=c.specs["resources"])
+ self.tracker.update(resources=c.specs["resources"], errors=c.specs["errors"])
  self.tracker.update(execute_and_jvp_batches=1, executions=len(batch), jvps=len(batch))
  self.tracker.record()
 
@@ -153,7 +155,7 @@ def execute_and_compute_vjp(
  if self.tracker.active:
  batch = (circuits,) if isinstance(circuits, QuantumScript) else circuits
  for c in batch:
- self.tracker.update(resources=c.specs["resources"])
+ self.tracker.update(resources=c.specs["resources"], errors=c.specs["errors"])
  self.tracker.update(execute_and_vjp_batches=1, executions=len(batch), vjps=len(batch))
  self.tracker.record()
  return untracked_execute_and_compute_vjp(self, circuits, cotangents, execution_config)
@@ -176,6 +178,7 @@ def simulator_tracking(cls: type) -> type:
  * ``executions``: the number of unique circuits that would be required on quantum hardware
  * ``shots``: the number of shots
  * ``resources``: the :class:`~.resource.Resources` for the executed circuit.
+ * ``"errors"``: combined algorithmic errors from the quantum operations executed by the qnode.
  * ``simulations``: the number of simulations performed. One simulation can cover multiple QPU executions,
  such as for non-commuting measurements and batched parameters.
  * ``batches``: The number of times :meth:`~pennylane.devices.Device.execute` is called.
@@ -218,7 +221,8 @@ def execute(self, circuits, execution_config = qml.devices.DefaultExecutionConfi
  'shots': [100],
  'resources': [Resources(num_wires=1, num_gates=1, gate_types=defaultdict(<class 'int'>, {'S': 1}),
  gate_sizes=defaultdict(<class 'int'>, {1: 1}), depth=1, shots=Shots(total_shots=50,
- shot_vector=(ShotCopies(50 shots x 1),)))]}
+ shot_vector=(ShotCopies(50 shots x 1),)))],
+ 'errors': {}}
 
  """
  if not issubclass(cls, Device):

pennylane/tracker.py

@@ -82,7 +82,9 @@ def circuit(x):
  gate_types=defaultdict(<class 'int'>, {'RX': 1}),
  gate_sizes=defaultdict(<class 'int'>, {1: 1}),
  depth=1,
- shots=Shots(total_shots=100, shot_vector=(ShotCopies(100 shots x 1),)))}
+ shots=Shots(total_shots=100, shot_vector=(ShotCopies(100 shots x 1),))),
+ 'errors': {}
+ }
  >>> tracker.history.keys()
  dict_keys(['batches', 'simulations', 'executions', 'results', 'shots', 'resources'])
  >>> tracker.history['results']

tests/devices/default_qubit/test_default_qubit_tracking.py

@@ -59,6 +59,7 @@ def test_tracking_batch(self):
  "resources": [Resources(num_wires=1), Resources(num_wires=1), Resources(num_wires=1)],
  "derivative_batches": [1],
  "derivatives": [1],
+ "errors": [{}, {}, {}],
  }
  assert tracker.totals == {
  "batches": 2,
@@ -73,6 +74,7 @@ def test_tracking_batch(self):
  "simulations": 1,
  "results": 1,
  "resources": Resources(num_wires=1),
+ "errors": {},
  }
 
  def test_tracking_execute_and_derivatives(self):
@@ -103,6 +105,7 @@ def test_tracking_execute_and_derivatives(self):
  "vjp_batches": [1],
  "execute_and_vjp_batches": [1],
  "resources": [Resources(num_wires=1)] * 12,
+ "errors": [{}] * 12,
  }
 
  def test_tracking_resources(self):

tests/devices/modifiers/test_all_modifiers.py

@@ -44,7 +44,7 @@ def execute(self, circuits, execution_config=qml.devices.DefaultExecutionConfig)
  # result unwrapped
  assert out == 0.0
 
- assert len(dev.tracker.history) == 6
+ assert len(dev.tracker.history) == 7
  assert dev.tracker.history["batches"] == [1]
  assert dev.tracker.history["simulations"] == [1]
  assert dev.tracker.history["executions"] == [1]

tests/devices/modifiers/test_simulator_tracking.py

@@ -44,7 +44,7 @@ def execute(self, circuits, execution_config=qml.devices.DefaultExecutionConfig)
  out = dev.execute((tape1, tape2))
 
  assert out == ((0.0, 0.0), 0.0)
- assert len(dev.tracker.history) == 6
+ assert len(dev.tracker.history) == 7
  assert dev.tracker.history["batches"] == [1]
  assert dev.tracker.history["simulations"] == [1, 1]
  assert dev.tracker.history["executions"] == [2, 2]

tests/devices/test_default_clifford.py

@@ -484,6 +484,7 @@ def test_tracker():
  "batches": [1, 1],
  "simulations": [1, 1],
  "executions": [1, 1],
+ "errors": [{}, {}],
  }
 
 

tests/devices/test_null_qubit.py

@@ -106,6 +106,7 @@ def test_tracking():
  )
  ]
  * 13,
+ "errors": [{}] * 13,
  }
 
 

tests/resource/test_error/test_error.py

@@ -282,3 +282,16 @@ def test_specs(self):
  assert algo_errors["MultiplicativeError"].error == 0.31 * 0.24
  assert algo_errors["AdditiveError"].error == 0.73 + 0.12
  assert algo_errors["SpectralNormError"].error == 0.25 + 0.17998560822421455
+
+ def test_tracker(self):
+ """Test that tracker are tracking errors as expected."""
+
+ with qml.Tracker(self.dev) as tracker:
+ self.circuit()
+
+ algo_errors = tracker.latest["errors"]
+ assert len(algo_errors) == 3
+ assert all(error in algo_errors for error in self.errors_types)
+ assert algo_errors["MultiplicativeError"].error == 0.31 * 0.24
+ assert algo_errors["AdditiveError"].error == 0.73 + 0.12
+ assert algo_errors["SpectralNormError"].error == 0.25 + 0.17998560822421455