Week 2 Assignment 4.3 - propagate function gives assert error despite apparently correct answer

Course Q&A Deep Learning Specialization Neural Networks and Deep Learning
1

Hi,
I am getting values that match the expected answer, but still receive assertion errors.

propagate_test(propagate)

dw = [[0.99845601]
 [2.39507239]]
db = 0.001455578136784208
cost = -5.801545319394553
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
<ipython-input-107-be03942b69a5> in <module>
     14 print ("cost = " + str(cost))
     15 
---> 16 propagate_test(propagate)

~/work/release/W2A2/public_tests.py in propagate_test(target)
     39     assert np.allclose(grads['dw'], expected_dw), f"Wrong values for grads['dw']. {grads['dw']} != {expected_dw}"
     40     assert np.allclose(grads['db'], expected_db), f"Wrong values for grads['db']. {grads['db']} != {expected_db}"
---> 41     assert np.allclose(cost, expected_cost), f"Wrong values for cost. {cost} != {expected_cost}"
     42     print('\033[92mAll tests passed!')
     43 

AssertionError: Wrong values for cost. -5.801545319394553 != 5.80154531

I can’t spot an error, and I also did add a cell to print out stuff, and then cut it out to get rid of it. Since then I’ve closed the notebook and opened it a few times but I still get the error.

I’d be grateful for any assistance

2

hello mentors and fellow students! Is there any way for me to fix this? My answer matches the “Expected answer” but I get an assert saying: AssertionError: Wrong values for cost. -5.801545319394553 != 5.80154531

Meanwhile the expected answer matches the answer I produced:
My answer:
dw = [[0.99845601]
[2.39507239]]
db = 0.001455578136784208
cost = -5.801545319394553

Expected output

dw = [[0.99845601]
 [2.39507239]]
db = 0.001455578136784208
cost = 5.801545319394553
3

Dear @zaks from the information you attached here it seems that the cost is negative 5.8 instead of positive 5.8, hope this helps

4

thank you - silly of me!