CODEWITHSUNDEEP
python
chrischris
chrischris

Reputation: 111

Code is unreachable -error

newb here, i am trying to compare the difference between a matrix and its tranposed matrix with a tollerance. First thing is i need to check that it is a square and then if the differnce is with tollerance.I am getting an error that the last two lines of codes are unreachable. The output should be True True for the above but I only get the first True (ie it is a square matrix.

import numpy as np
a= np.array(([[1, 2, 3,],[2, 3, 4],[3, 4, 1]]))

def check_symmetric(a,tol):
    b = a.transpose(1, 0)
    print (a)
    print(b)
    rows = a.shape[1]
    col = a.shape[0]
    z= abs(a-b)
    print(z)
    if rows != col: #check to make sure the list is a square
            return False
    return True;
    result = (abs(a - b) <= tol).all()
    print(result)



print check_symmetric(a,tol=1e-8)

Upvotes: 0

Views: 54191

Answers (2)

Ananth Rao
Ananth Rao

Reputation: 1252

Move your return statement to the bottom of the function:

return True;
result = (abs(a - b) <= tol).all()
print(result)

would become:

result = (abs(a - b) <= tol).all()
print(result)
return True;

A return statement will stop the execution of a function and return control back to the context it was called from, in this case the line:

print check_symmetric(a,tol=1e-8)

That means the way your code is right now, the last two lines will never be executed because the context for execution is back outside the function already. That's why you don't see that second print statement.

Upvotes: 3

Ricardo C&#225;rdenes
Ricardo C&#225;rdenes

Reputation: 9172

There's a return True; just before the last two lines. The function will return at that point, and will never execute those lines. That's why they're unreachable.

Most probably you want to move that line to the end?

Upvotes: 1

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