# Bad example for variational classifier iris classification demo

**URL:** <https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842>\
**Category:** PennyLane Help\
**Created:** [April 18, 2022, 2:35pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842 "2022-04-18T14:35:58Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![tudouuuuu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/tudouuuuu/32/1001_2.png) [@tudouuuuu](https://discuss.pennylane.ai/u/tudouuuuu)\
**Post date:** [April 18, 2022, 2:35pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/1 "2022-04-18T14:35:58Z")

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Hello,  
I use this iris data in variational classifier iris classification demo.

```
import pandas as pd
from sklearn import datasets

iris = datasets.load_iris()

df = pd.DataFrame(iris.data, columns=iris.feature_names)
df['target'] = iris.target
df['target_names'] = iris.target_names[iris.target]
df.head()

x_train = df.loc[:, ['petal length (cm)', 'petal width (cm)']].to_numpy()

y_train = iris.target
y_train = [int(e / 2) for e in y_train]

X = x_train
Y = [(-1 if e==1 else 1) for e in y_train]
Y = np.tensor(Y, requires_grad=True)

```

But I get the bad result. I wonder how to improve model or why.

 ![wa3](https://canada1.discourse-cdn.com/flex012/uploads/pennylane/original/2X/f/fa8271290ecbffe028d53fe0bf87d7a2fb16008f.png)

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<div class="post-metadata">

**Author:** ![isaacdevlugt](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/isaacdevlugt/32/1159_2.png) [@isaacdevlugt](https://discuss.pennylane.ai/u/isaacdevlugt)\
**Post date:** [April 18, 2022, 9:34pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/2 "2022-04-18T21:34:29Z")

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Hey @tudouuuuu!

Just want to make sure that you’re referring to [this demo](https://pennylane.ai/qml/demos/tutorial_variational_classifier.html)? I.e., you’re using the code in the [Iris Classification](https://pennylane.ai/qml/demos/tutorial_variational_classifier.html#iris-classification) section but just replacing the data there with the content in your post?

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<div class="post-metadata">

**Author:** ![tudouuuuu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/tudouuuuu/32/1001_2.png) [@tudouuuuu](https://discuss.pennylane.ai/u/tudouuuuu)\
**Post date:** [April 19, 2022, 6:40am UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/3 "2022-04-19T06:40:35Z")

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Yes, I am using code in the [Iris classification](https://pennylane.ai/qml/demos/tutorial_variational_classifier.html#iris-classification)

I also changed last plot code. I replaced `xx, yy` in this way:

Before:

```
xx, yy = np.meshgrid(np.linspace(0.0, 1.5, 20), np.linspace(0.0, 1.5, 20))

```

After:

```
xx, yy = np.meshgrid(np.arange(X[:, 0].min() - 0.5, X[:, 0].max() + 0.5, 0.05), np.arange(X[:, 1].min() - 0.5, X[:, 1].max() + 0.5, 0.05))
```

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<div class="post-metadata">

**Author:** ![isaacdevlugt](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/isaacdevlugt/32/1159_2.png) [@isaacdevlugt](https://discuss.pennylane.ai/u/isaacdevlugt)\
**Post date:** [April 19, 2022, 1:18pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/4 "2022-04-19T13:18:35Z")

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Could you please attach the notebook that you’re working with? It’s hard to pinpoint exactly what’s going on without seeing your entire code.

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<div class="post-metadata">

**Author:** ![tudouuuuu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/tudouuuuu/32/1001_2.png) [@tudouuuuu](https://discuss.pennylane.ai/u/tudouuuuu)\
**Post date:** [April 19, 2022, 1:52pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/5 "2022-04-19T13:52:17Z")

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Please look [here](https://colab.research.google.com/drive/10wfKpfGXH5dpvhNz1POJNXlrcVw5Px9b?usp=sharing)

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<div class="post-metadata">

**Author:** ![tudouuuuu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/tudouuuuu/32/1001_2.png) [@tudouuuuu](https://discuss.pennylane.ai/u/tudouuuuu)\
**Post date:** [April 19, 2022, 2:42pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/6 "2022-04-19T14:42:19Z")

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I find when I change the number of iteration to 51 or 52, the result is good.  
Thanks for your reply! @isaacdevlugt

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<div class="post-metadata">

**Author:** ![isaacdevlugt](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/isaacdevlugt/32/1159_2.png) [@isaacdevlugt](https://discuss.pennylane.ai/u/isaacdevlugt)\
**Post date:** [April 19, 2022, 2:57pm UTC](https://discuss.pennylane.ai/t/bad-example-for-variational-classifier-iris-classification-demo/1842/7 "2022-04-19T14:57:34Z")

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Glad your issue is solved! I suspected it was probably just an issue with hyperparameter choices… Awesome job!