C1_W4_Assignment Excersise - 2

Hi, I think there is a bug in the plot_transformation function.

After inserting values, the plot is supposed to look like this.

but even after inserting the correct values, the output looks like this.

As you can see all the tests were passed and I got a grade on it. I just want to let the team know.

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Hi, thanks for flagging this issue! I will inform our Curriculum Engineer.


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Copy paste error. Something wrong with

A_shear_x = np.array([[1,0],[0.5,1]])

Find eigenvalues and eigenvectors or matrix A_reflection_yaxis.

A_shear_x_eig = np.linalg.eig(A_shear_x)

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I still see the same issue described above. The plot of the shear is not correct, although the unit test passes.

Hi all!

Sorry for delaying any return. This is in fact not a bug.

As a direct quote from our curriculum engineer:

In the first figure, the transformation is visualized with the transformation of the basis vectors. The second figure shows the transformation of the eigenvectors. There is only one eigenvalue (actually, two that are equal to each other), so the visualization of the transformation applied to the eigenvectors does look different.

Here’s what I got after inserting the correct values in places:


These are not even proper Eigenvectors.
is this a bug? or should I recheck my values?
and some of the tests are passed, not all.

If that’s for A_shear_x, it appears to me that your plot is incorrect.

What code did you use?

sorry, my values were incorrect, now there is no problem with the values but with the plot. All test passed but the plot doesn’t look like sheared:


I agree, the plot is surprising.

It’s explained a bit in the staff reply earlier in this thread.