Python comparing two matrices produces error-CodePudding

Hello I have the following code which transposes one matrix and compares it to the original matrix in order to check if the matrix is symetrical.

def sym(x):
    
    mat = x
    transpose = 0;
    
    (m,n) = x.shape
    if(m != n):
        print("Matrix must be square")
        return
    else:
        transpose = ([[x[j][i] for j in range(len(x))] for i in range(len(x[0]))])
        print(transpose)
        print(x)
        if(transpose == mat):
           print("Symetrical")
        else:
           print("Not symetrical")
            
        return
    
    A = np.random.rand(5,5)
    SymMatrix = (A   A.T)/2
    sym(SymMatrix)

I recieve the following data from the prints:

[[0.17439677739055337, 0.4578837676040824, 0.35842887026076997, 0.8610456087667133,      0.2967753611380975], [0.4578837676040824, 0.6694101430064164, 0.6718596412137644, 0.5107862111816033, 0.6429698779871544], [0.35842887026076997, 0.6718596412137644, 0.5387701626024015, 0.708555677626843, 0.5756758392540096], [0.8610456087667133, 0.5107862111816033, 0.708555677626843, 0.37095928395815847, 0.7062962356554356], [0.2967753611380975, 0.6429698779871544, 0.5756758392540096, 0.7062962356554356, 0.3807024190850993]]

    [[0.17439678 0.45788377 0.35842887 0.86104561 0.29677536]
     [0.45788377 0.66941014 0.67185964 0.51078621 0.64296988]
     [0.35842887 0.67185964 0.53877016 0.70855568 0.57567584]
     [0.86104561 0.51078621 0.70855568 0.37095928 0.70629624]
     [0.29677536 0.64296988 0.57567584 0.70629624 0.38070242]]

along with this error:

  The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

The first issue i see is that the transposes matrix has extra decimals in each value which i dont understand and I am not sure if this is the cause of the error. Any help on this would be appreciated. Thanks!

CodePudding user response：

What you are doing is trying to compare two ndarrays, which results in something like this:

transpose == mat
array([[ True,  True,  True,  True,  True],
       [ True,  True,  True,  True,  True],
       [ True,  True,  True,  True,  True],
       [ True,  True,  True,  True,  True],
       [ True,  True,  True,  True,  True]])

The 'if' statement does not know which boolean he should pick. Should it be Trueif any of the values are True, or only if all values are True?

To indicate that all values should be True, add: .all() to your statement:

if((transpose == mat).all())

This results in a single boolean (in this case: True).