Passed all test but just got 70% score cause the gaussian elimination 0/35 even though it "Passed all tests"

[AnhDuck]

I don’t really understand why I met this error at gaussian elimination section, although the back substitution is fully correct and row_echelon_form too (35/35 for both but 0/35 for gaussian section, even though the w2 unit test still give me passed all test for this part!)

[gent.spah]

The error tells you that variable M is not defined previoulsy so the grader is throwing an error. Check what is assigned to variable M, maybe you are using it inside a loop right way without defining it initially.

[AnhDuck]

Thanks!