class_docstr: Test caching for device jacobians.
class_docstr_tok: ["Test","caching","for","device","jacobians","."]
docstr: Test that execute_and_compute_jacobians caches results and Jacobians if they are not precalculated.
docstr_tok: ["Test","that","execute_and_compute_jacobians","caches","results","and","Jacobians","if","they","are","not","precalculated","."]
code: def test_cached_on_execute_and_compute_jacobian(self, jpc):
      """Test that execute_and_compute_jacobians caches results and Jacobians if they are not precalculated."""
      x = 1.5
      tape1 = qml.tape.QuantumScript(
          [qml.Hadamard(0), qml.IsingXX(x, wires=(0, 1))],
          [qml.expval(qml.PauliZ(1))],
      )
      batch = (tape1,)
  
      with jpc._device.tracker:
          res, jacs = jpc.execute_and_compute_jacobian(batch)
  
      assert (
          jpc._device.tracker.totals["execute_and_derivative_batches"]
          == 1
      )
  
      assert qml.math.allclose(res, np.cos(x))
      assert qml.math.allclose(jacs, -np.sin(x))
  
      assert jpc._results_cache[batch] is res
      assert qml.math.allclose(jpc._jacs_cache[batch], (-np.sin(x)))
  
      with jpc._device.tracker:
          jpc.execute_and_compute_jacobian(batch)
  
      assert jpc._device.tracker.totals.get("derivatives", 0) == 0
      assert jpc._device.tracker.totals.get("executions", 0) == 0
  
imports: import pytest
  from cachetools import LRUCache
  from param_shift_dev import ParamShiftDerivativesDevice
  import numpy
  import pennylane
  from pennylane.workflow.jacobian_products import JacobianProductCalculator, TransformJacobianProducts, DeviceDerivatives, DeviceJacobianProducts, LightningVJPs
label_desc: Use image node_id 3 for calling the TestCachingDeviceDerivatives obj's underlying member method code with example usage: obj.test_cached_on_execute_and_compute_jacobian(jpc) without return types