Week 2 practice lab: Linear regression. Assertion error

Course Q&A Machine Learning Specialization Supervised ML: Regression and Classification
1

Hi,
On exercice 1, after adding the code:

### START CODE HERE ###
# mentor edit: code removed
### END CODE HERE ###

I tried to check if the implementation was correct so I tried to run the test code below but it displays:
<class ‘float’>
Cost at initial w: 0.000

AssertionError Traceback (most recent call last)
in
9 # Public tests
10 from public_tests import *
—> 11 compute_cost_test(compute_cost)

~/work/public_tests.py in compute_cost_test(target)
17 initial_b = 1.0
18 cost = target(x, y, initial_w, initial_b)
—> 19 assert cost == 2, f"Case 2: Cost must be 2 but got {cost}"
20
21 # print(“Using X with shape (5, 1)”)

AssertionError: Case 2: Cost must be 2 but got 0.0

What can I do?
Thank’s

2

  1. Please do not share your code on the forum. That’s not allowed by the Code of Conduct. Posting your error messages is a better method. If a mentor needs to see your code, we’ll contact you with instructions.

  2. Hint: Does your code ever update the value in cost_sum?

1 Like
3
  1. OK, sorry for that.
  2. No it doesn’t.
4

Were you able to fix the issue?

5

Yes, thank you.

1 Like
6

Hi all, I need help with the 1st assignment for C1 W2. I am having trouble navigating the datasets in jupyter notebook. Please help. Thanks

7

What exactly do you mean by “navigating the datasets”? I don’t think any navigation is necessary.

If you follow along in the instructions in the notebook, and come to something you don’t understand or doesn’t work, please post a screen capture image of the issue.

Note that you should not post an image of your code.

8

having a problem with cost function and receive this error

Screenshot 2025-03-11 at 4.35.50 PM
Screenshot 2025-03-11 at 4.35.50 PM1948×846 101 KB

Screenshot 2025-03-11 at 4.35.50 PM
Screenshot 2025-03-11 at 4.35.50 PM1948×846 101 KB

9

Before your code enters the for-loop, did you give cost_sum an initial value?

10

yes, i set cost and cost_sum and total_cost = 0. the instructions state " # You need to return this variable correctly" ??

11

got it, needed to go back and rerun each section independently, damn

1 Like
12

Always re-run every cell that you modify. It isn’t automatic.

13

i am running the same code as the optional lab for week 3 excercise 3 and getting this error File “”, line 24
err_i = f_wb_i - y[i]
^
SyntaxError: invalid syntax.

Screenshot 2025-03-13 at 1.57.54 PM
Screenshot 2025-03-13 at 1.57.54 PM1392×602 53.9 KB

14

The syntax error is somewhere prior to the first character in the “err_i = …” line.

Which optional lab exactly are you using as a reference? Week 3 has nine optional labs.

Your thread title uses the Week 2 tag, by which I assume you’re working on the linear regression assignment, which does not use sigmoid().

Update: It appears you’re using code from optional lab C1_W3_Lab06.

15

The only optional lab related to computing gradients for logistic regression: Optional lab: Gradient descent for logistic regression

16

If you’re working on the Week 2 graded assignment (as your thread title indicates), you should not be using code that includes sigmoid().

The syntax error may be due to copy-and-paste that includes some non-printable character. Try deleting the indentation from that line, and re-insert it.