Add GateFabric Template #1687
Add GateFabric Template #1687
Conversation
Co-authored-by: Josh Izaac <josh146@gmail.com>
…o add-gate-fabric
…o add-gate-fabric
pennylane/init.py
Outdated
| @@ -1127,3 +1127,69 @@ def basic_entangler_layers_uniform(n_layers, n_wires, low=0, high=2 * pi, seed=N | |||
| params = np.random.uniform(low=low, high=high, size=(n_layers, n_wires)) | |||
|
|
|||
| return params | |||
|
|
|||
|
|
|||
| def gate_fabric_uniform(n_layers, n_wires, low=0, high=2 * pi, seed=None): | |||
There was a problem hiding this comment.
oh @obliviateandsurrender we haven't done a very good job of documenting it, but the init module is deprecated! Instead of adding new functions here, the preferred approach is to have a shape method on the template itself:
>>> shape = qml.templates.StronglyEntanglingLayers.shape(n_layers=3, n_wires=2)
>>> np.random.random(shape)
array([[[0.48715978, 0.24741362, 0.19435542],
[0.54890558, 0.58210102, 0.98678809]],
[[0.43263127, 0.09268041, 0.4359657 ],
[0.34308469, 0.79198242, 0.81406353]],
[[0.80658304, 0.45946463, 0.66767815],
[0.75200523, 0.46483252, 0.02140596]]])This has the advantage that we don't need to wrap NumPy's random module, worry about seeds, etc.
Also tagging @antalszava and @mariaschuld here for visibility; we should decide if we remove/fully deprecate this module.
There was a problem hiding this comment.
Hey @josh146! I am sorry I did not know about init module's depreciation. Anyhow, I already had included the shape method in GateFabric template. I have now removed the previously added functions from the init.
There was a problem hiding this comment.
No worries at all, the PennyLane documentation was not clear as to the status of the init module 🙂 This is something we should address
There was a problem hiding this comment.
Maybe for now we can just add a note in the docstring and/or remove it from the documentation and all tutorials? So it would still work, but people won't find it or add to it?
There was a problem hiding this comment.
👍 Let's also add it to one of our upcoming deprecation cycles @antalszava, so that we don't forget about it
There was a problem hiding this comment.
I started a PR here...
There was a problem hiding this comment.
Just to summarize, would the following sound good?
- v0.19.0 (next release):
- The
initmodule is still available, but not advertised in the docs and a deprecation warning has been added as per Deprecate init module #1689 - Demos don't use the
initmodule anymore
- The
- v0.20.0: the
initmodule is completely removed from PennyLane
| """ | ||
| num_params = 1 | ||
| num_wires = AnyWires | ||
| par_domain = "A" |
There was a problem hiding this comment.
@obliviateandsurrender is there a known gradient recipe for this gate? If not, best to have grad_method=None
There was a problem hiding this comment.
I have added the grad_method=None. I am assuming that by gate you meant the overall unitary block made by the template and not the gates (OrbitalRotation and DoubleExcitation) it is composed of because for them four-term parameter-shift rule exists.
There was a problem hiding this comment.
Also, would you have an idea about why in Tests/core-tests(3.8, tf, torch, jax), the tests TestPassthruIntegration::test_prob_differentiability and TestPassthruIntegration::test_backprop_gradient are failing? I am unable to replicate the error in my local machine.
There was a problem hiding this comment.
I have added the grad_method=None. I am assuming that by gate you meant the overall unitary block made by the template and not the gates (OrbitalRotation and DoubleExcitation) it is composed of because for them four-term parameter-shift rule exists.
Yep, exactly 👍
I am unable to replicate the error in my local machine.
Oh this is very interesting, the same thing was happening to me in my PR yesterday: #1685. It must be related either to:
- A new release of JAX?
- A change in
masterthat has affected the test suite
There was a problem hiding this comment.
There seems to have been a new release of JAX made on the 24th of September: https://pypi.org/project/jax/#history
Perhaps this is the cause
There was a problem hiding this comment.
Can confirm that this is it after checking locally. 🙂 Let me open a PR.
Codecov Report
@@ Coverage Diff @@
## master #1687 +/- ##
=======================================
Coverage 99.21% 99.21%
=======================================
Files 202 203 +1
Lines 15253 15300 +47
=======================================
+ Hits 15133 15180 +47
Misses 120 120
Continue to review full report at Codecov.
|
| ansatz = partial(GateFabric, init_state=ref_state, include_pi=True) | ||
|
|
||
| # Define the cost function | ||
| cost_fn = qml.ExpvalCost(ansatz, h, dev) |
There was a problem hiding this comment.
Might consider having an example that works with expval(H).
There was a problem hiding this comment.
Yes, I have changed the example now with one with expval(H).
| assert res_wires == exp_wires | ||
|
|
||
| @pytest.mark.parametrize( | ||
| ("init_state", "exp_state"), |
There was a problem hiding this comment.
How the exp_state is computed?
There was a problem hiding this comment.
I compute them manually with the first matrix multiplication of the gates and then cross-check them with a manually decomposed version of GateFabric.
| ], | ||
| ) | ||
| def test_decomposition_q(self, init_state, exp_state, tol): | ||
| """Test the decomposition of the Q_{theta, phi}` exchange gate by asserting the prepared |
There was a problem hiding this comment.
Should be changed to :math:Q_{theta, phi}. Is it just a general decomposition test? (what is Q exchange gate?)
There was a problem hiding this comment.
Yeah, fixed it. This is just to test correctness of Q gate (removed the word exchange) which makes up the GateFabric template.
| print(init_state, exp_state) | ||
|
|
||
| @qml.qnode(dev) | ||
| def circuit(weight): |
There was a problem hiding this comment.
Is there any test for n_layer > 1?
There was a problem hiding this comment.
Added two new tests for n_layers > 1.
| # See the License for the specific language governing permissions and | ||
| # limitations under the License. | ||
| r""" | ||
| Contains the quantum number preserving GateFabric template. |
There was a problem hiding this comment.
| Contains the quantum number preserving GateFabric template. | |
| Contains the quantum-number-preserving GateFabric template. |
| r"""Implements a local, expressive, and quantum-number-preserving ansatz using VQE circuit fabrics | ||
| proposed by Anselmetti *et al.* in `arXiv:2104.05692 <https://arxiv.org/abs/2104.05695>`_. |
There was a problem hiding this comment.
| r"""Implements a local, expressive, and quantum-number-preserving ansatz using VQE circuit fabrics | |
| proposed by Anselmetti *et al.* in `arXiv:2104.05692 <https://arxiv.org/abs/2104.05695>`_. | |
| r"""Implements a local, expressive, and quantum-number-preserving ansatz | |
| proposed by Anselmetti *et al.* in `arXiv:2104.05692 <https://arxiv.org/abs/2104.05695>`_. |
| This template prepares the :math:`N` qubits trial state by applying :math:`D` layers of gate fabric block | ||
| :math:`\hat{U}_{GF}(\vec{\theta},\vec{\phi})` to the Hartree-Fock state in the Jordan-Wigner basis |
There was a problem hiding this comment.
| This template prepares the :math:`N` qubits trial state by applying :math:`D` layers of gate fabric block | |
| :math:`\hat{U}_{GF}(\vec{\theta},\vec{\phi})` to the Hartree-Fock state in the Jordan-Wigner basis | |
| This template prepares the :math:`N`-qubit trial state by applying :math:`D` layers of gate-fabric blocks | |
| :math:`\hat{U}_{GF}(\vec{\theta},\vec{\phi})` to the Hartree-Fock state in the Jordan-Wigner basis |
| \vert \Psi(\vec{\theta},\vec{\phi})\rangle = | ||
| \hat{U}_{GF}^{(D)}(\vec{\theta}_{D},\vec{\phi}_{D}) \ldots | ||
| \hat{U}_{GF}^{(2)}(\vec{\theta}_{2},\vec{\phi}_{2}) | ||
| \hat{U}_{GF}^{(1)}(\vec{\theta}_{1},\vec{\phi}_{1}) \vert HF \rangle |
There was a problem hiding this comment.
| \hat{U}_{GF}^{(1)}(\vec{\theta}_{1},\vec{\phi}_{1}) \vert HF \rangle | |
| \hat{U}_{GF}^{(1)}(\vec{\theta}_{1},\vec{\phi}_{1}) \vert HF \rangle, |
| \hat{U}_{GF}^{(2)}(\vec{\theta}_{2},\vec{\phi}_{2}) | ||
| \hat{U}_{GF}^{(1)}(\vec{\theta}_{1},\vec{\phi}_{1}) \vert HF \rangle | ||
|
|
||
| where each of the gate fabric block :math:`\hat{U}_{GF}(\vec{\theta},\vec{\phi})` comprises of 2-parameter 4-qubit |
There was a problem hiding this comment.
| where each of the gate fabric block :math:`\hat{U}_{GF}(\vec{\theta},\vec{\phi})` comprises of 2-parameter 4-qubit | |
| where each of the gate fabric blocks :math:`\hat{U}_{GF}(\vec{\theta},\vec{\phi})` is comprised of two-parameter four-qubit |
| .. UsageDetails:: | ||
|
|
||
| #. The number of wires :math:`N` has to be equal to the number of | ||
| spin orbitals included in the active space, and should be even. |
There was a problem hiding this comment.
| spin orbitals included in the active space, and should be even. | |
| spin-orbitals included in the active space, and should be even. |
| weights = np.random.random(size=shape) | ||
|
|
||
| >>> weights.shape | ||
| (2, 1, 2) |
There was a problem hiding this comment.
Excellent usage details! Great job!
|
|
||
| def __init__(self, weights, wires, init_state, include_pi=False, do_queue=True, id=None): | ||
|
|
||
| if len(wires) < 4: |
| ) | ||
| if len(wires) % 2: | ||
| raise ValueError( | ||
| f"This template requires even number of qubits; got {len(wires)} wires" |
There was a problem hiding this comment.
| f"This template requires even number of qubits; got {len(wires)} wires" | |
| f"This template requires an even number of qubits; got {len(wires)} wires" |
| par_domain = "A" | ||
| grad_method = None | ||
|
|
||
| def __init__(self, weights, wires, init_state, include_pi=False, do_queue=True, id=None): |
There was a problem hiding this comment.
I like the include_pi approach 👍
…ender/pennylane into add-gate-fabric
…ender/pennylane into add-gate-fabric
|
@ixfoduap I have incorporated all the requested changes in the docstrings, header, and have included a VQE usage example in the |
doc/releases/changelog-dev.md
Outdated
|
|
||
| ```python | ||
| coordinates = np.array([0.0, 0.0, -0.6614, 0.0, 0.0, 0.6614]) | ||
| H, qubits = qml.qchem.molecular_hamiltonian(symbols = ["H", "H"], coordinates) |
There was a problem hiding this comment.
| H, qubits = qml.qchem.molecular_hamiltonian(symbols = ["H", "H"], coordinates) | |
| H, qubits = qml.qchem.molecular_hamiltonian(["H", "H"], coordinates) |
I think this should work, but good to double-check
doc/releases/changelog-dev.md
Outdated
| Final value of the ground-state energy = -1.13618883 Ha | ||
|
|
||
| Optimal value of the circuit parameters = [[[ 0.58835515 0.40801101]] | ||
| [[ 0.83842218 -0.24228264]]] |
There was a problem hiding this comment.
This is a great entry to the changelog, but I wonder if it is too long for our usual standards. Any thoughts @josh146 @antalszava?
If we agree it's too long, you can just end it on line 234 where the circuit is defined
There was a problem hiding this comment.
Yep, agree it is a great changelog entry, but potentially too much information. I suggest truncating at line 234. You can then have something such as
For more details, see the [GateFabric documentation](url).You could even take the training example here, and add it to the GateFabric docstring under .. UsageDetails::!
There was a problem hiding this comment.
I have truncated the changelog entry as requested and have shifted the VQE usage example to .. UsageDetails::.
Context:
This is the second part of the PRs aimed at adding the
GateFabrictemplate, which is based on the local, expressive, and quantum number preserving ansatz presented in arXiv:2104.05695.Description of the Change:
Function
GateFabricprovides the implementation for the quantum number preserving gate fabric.Relevant UnitTests and init definitions for
GateFabricoperation.Benefits:
This will expand the current set of Pennylane's templates with a new local and expressive VQE circuit fabric.
Possible Drawbacks:
No specific drawbacks.
Related GitHub Issues:
No related issues.