class_docstr: Test the new VQE syntax of passing the Hamiltonian as an observable.
class_docstr_tok: ["Test","the","new","VQE","syntax","of","passing","the","Hamiltonian","as","an","observable","."]
docstr: Tests VQE gradients in the torch interface.
docstr_tok: ["Tests","VQE","gradients","in","the","torch","interface","."]
code: def test_grad_torch(self, tol):
      """Tests VQE gradients in the torch interface."""
      import torch
  
      dev = qml.device("default.qubit", wires=4)
      H = big_hamiltonian
  
      @qml.qnode(dev)
      def circuit(w):
          qml.templates.StronglyEntanglingLayers(w, wires=range(4))
          return qml.expval(H)
  
      w = torch.tensor(PARAMS, requires_grad=True)
  
      res = circuit(w)
      res.backward()  # pylint:disable=no-member
      dc = w.grad.detach().numpy()
  
      assert np.allclose(dc, big_hamiltonian_grad, atol=tol)
  
imports: import copy
  import numpy
  import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 11 for calling the TestNewVQE obj's underlying member method code with example usage: obj.test_grad_torch(tol) and returns: qml