# Course 3, Week 1, Anomaly Detection Programming Assignement **URL:** \ **Category:** Unsupervised Learning, Recommenders, Reinforcement\ **Tags:** week-module-1\ **Created:** [August 7, 2024, 1:00am UTC](https://community.deeplearning.ai/t/course-3-week-1-anomaly-detection-programming-assignement/674277 "2024-08-07T01:00:50Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Francois\_Poirier](https://avatars.discourse-cdn.com/v4/letter/f/7ba0ec/32.png) [@Francois\_Poirier](https://community.deeplearning.ai/u/Francois_Poirier)\ **Post date:** [August 7, 2024, 1:00am UTC](https://community.deeplearning.ai/t/course-3-week-1-anomaly-detection-programming-assignement/674277/1 "2024-08-07T01:00:50Z")
Hi, I am getting a weird error when running my code with a numpy array to calculate the mean (mu) and the variance (var) in the assignment. I am not sure how to debug this, as my code calculates the values properly. I have no clue what the stack trace is reporting, let alone this line: ```auto AssertionError: Wrong value for mu. Expected: [1, 2, 3] got: [1. 2. 0.] ``` Here is the unit test results: ```auto mu[0]: 14.1122257839456 mu[1]: 14.99771050813621 sum_var0/m 562.6178439428168 307 1.8326314134945172 sum_var1/m 524.891816564435 307 1.7097453308287784 var[0]: 1.8326314134945172 var[1]: 1.7097453308287784 END Mean of each feature: [14.11222578 14.99771051 0.] Variance of each feature: [1.83263141 1.70974533 0.] mu[0]: 1.0 mu[1]: 2.0 sum_var0/m 0.0 3 0.0 sum_var1/m 0.0 3 0.0 var[0]: 0.0 var[1]: 0.0 END --------------------------------------------------------------------------- AssertionError Traceback (most recent call last) in 7 # UNIT TEST 8 from public_tests import * ----> 9 estimate_gaussian_test(estimate_gaussian) ~/work/public_tests.py in estimate_gaussian_test(target) 44 assert type(var) == np.ndarray, f"Wrong shape for var. Expected: {(X.shape[1],)} got: {var.shape}" 45 ---> 46 assert np.allclose(mu, [1., 2., 3.]), f"Wrong value for mu. Expected: {[1, 2, 3]} got: {mu}" 47 assert np.allclose(var, [0., 0., 0.]), f"Wrong value for var. Expected: {[0, 0, 0]} got: {var}" 48 AssertionError: Wrong value for mu. Expected: [1, 2, 3] got: [1. 2. 0.] ``` Here’s how I defined my numpy arrays at the top of the program: ```auto mu = np.array([0, 0, 0], dtype=float) var = np.array([0, 0, 0], dtype=float) ``` Feel free to reply if you have any idea Thanks ---
**Author:** ![TMosh](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/tmosh/32/9321_2.png) [@TMosh](https://community.deeplearning.ai/u/TMosh)\ **Post date:** [August 7, 2024, 1:15am UTC](https://community.deeplearning.ai/t/course-3-week-1-anomaly-detection-programming-assignement/674277/2 "2024-08-07T01:15:02Z")
Defining your own test data isn’t effective, because the notebook code doesn’t know in advance what the correct results should be. The test that is failing is included in the public\_tests.py file, you can read it using the File → Open menu. It’s in the estimate\_gaussian\_test() function. Then you can see what data your code isn’t handling correctly. ---
**Author:** ![rmwkwok](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/rmwkwok/32/126977_2.png) [@rmwkwok](https://community.deeplearning.ai/u/rmwkwok)\ **Post date:** [August 7, 2024, 7:47am UTC](https://community.deeplearning.ai/t/course-3-week-1-anomaly-detection-programming-assignement/674277/3 "2024-08-07T07:47:32Z")
> [@Francois\_Poirier](#): > > Here’s how I defined my numpy arrays at the top of the program: > > mu = np.array([0, 0, 0], dtype=float) > var = np.array([0, 0, 0], dtype=float) Hello, @Francois_Poirier, did you initialize the `mu` and `var` with zeros and fill in the computed values one-by-one? If so, it seems to me that you were only filling in the first two answers at least for `mu`, which is why you got: > [@Francois\_Poirier](#): > > AssertionError: Wrong value for mu. Expected: [1, 2, 3] got: [1. 2. 0.] -which is saying that it expects `[1, 2, 3]` for `mu` but your program returned `[1, 2, 0]`. See? The first two values are correct but not the third. As for why it was expecting these 3 values, you might follow Tom’s reply to check out the actual input of the test, then you will see the reason. * * * * * * I recommend you to open the “hints” right below that exercise in which 2 ways are suggested. In particular, if you try the second way, you will not need to initialize `mu` or `var`, instead that will require you to know how to use `np.sum`. `np.sum` is a handy function that, as long as we are in the machine learning field, we will have to know it. In case you have not used it, perhaps this is a good time for you to give it a try. For example, you may run a code cell like below: ```auto import numpy as np X = np.array([ [1, 1, 1], [3, 5, 2], [7, 6, 3], ]) print(....) # use np.sum here ``` and see if you can use `np.sum` to calculate the row-wise sum and the column-wise sum of `X` correctly. Good luck to you, @Francois_Poirier 😉 Cheers, Raymond ---
**Author:** ![rmwkwok](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/rmwkwok/32/126977_2.png) [@rmwkwok](https://community.deeplearning.ai/u/rmwkwok)\ **Post date:** [August 7, 2024, 7:50am UTC](https://community.deeplearning.ai/t/course-3-week-1-anomaly-detection-programming-assignement/674277/4 "2024-08-07T07:50:38Z")
I have edited your post for proper code formatting. You may edit your post to see what changes I have made.