# Codebook: Quantum Circuits

**URL:** <https://discuss.pennylane.ai/t/codebook-quantum-circuits/4949>\
**Category:** Codebook\
**Created:** [July 29, 2024, 3:05pm UTC](https://discuss.pennylane.ai/t/codebook-quantum-circuits/4949 "2024-07-29T15:05:11Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![CatalinaAlbornoz](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/catalinaalbornoz/32/1196_2.png) [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\
**Post date:** [July 29, 2024, 3:05pm UTC](https://discuss.pennylane.ai/t/codebook-quantum-circuits/4949/1 "2024-07-29T15:05:11Z")

</div>

Ask here about the [“Quantum Circuits” Codebook topic](https://pennylane.ai/codebook/01-introduction-to-quantum-computing/02-quantum-circuits/) from the “Introduction to Quantum Computing” module.

---

<div class="post-metadata">

**Author:** ![marsiuniub](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/marsiuniub/32/3607_2.png) [@marsiuniub](https://discuss.pennylane.ai/u/marsiuniub)\
**Post date:** [March 7, 2025, 10:14am UTC](https://discuss.pennylane.ai/t/codebook-quantum-circuits/4949/2 "2025-03-07T10:14:31Z")

</div>

Hi. I am trying to solve Codercise PF.4.2 - A strong entangler. My question is about the test\_weights shape. In our special case, it should have a shape of (1, 4, 3), since we have one layer, four wires, and three parameters per wire. I have defined

test\_weights = np.array([[  
[0.1, 0.2, 0.3], # Qubit 1 parameters: α0, β0, δ0  
[0.4, 0.5, 0.6], # Qubit 2 parameters: α1, β1, δ1  
[0.7, 0.8, 0.9], # Qubit 3 parameters: α2, β2, δ2  
[1.0, 1.1, 1.2] # Qubit 4 parameters: α3, β3, δ3  
]])

but this error keeps being raised:

Error: Incorrect: Your test\_weights array doesn’t have the right format!.

I do not understand why. I have even tried adding requires\_grad = False, but still does not work. Any help would be appreciated.

---

<div class="post-metadata">

**Author:** ![daniela.murcillo](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/daniela.murcillo/32/3612_2.png) [@daniela.murcillo](https://discuss.pennylane.ai/u/daniela.murcillo)\
**Post date:** [March 7, 2025, 8:07pm UTC](https://discuss.pennylane.ai/t/codebook-quantum-circuits/4949/3 "2025-03-07T20:07:21Z")

</div>

Hi @marsiuniub!  
Welcome to the forum and thanks for your question.  
You are right, your `test_weights` array has the right shape, (1, 4, 3).  
This was an error on our code regarding validation tests (no need to worry about those).  
We have corrected it now.

Give it another try and let me know if it works.

---

<div class="post-metadata">

**Author:** ![marsiuniub](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/marsiuniub/32/3607_2.png) [@marsiuniub](https://discuss.pennylane.ai/u/marsiuniub)\
**Post date:** [March 8, 2025, 9:02am UTC](https://discuss.pennylane.ai/t/codebook-quantum-circuits/4949/4 "2025-03-08T09:02:22Z")

</div>

Now it works! Thank you very much 😊