def zeroes(n, m):
    result = []
    # iterate through rows of X
    for i in range(n):
       a = []
       # iterate through columns of Y
       for j in range(m):
           a.append(0.0)
       result.append(a)
    return result

def diag(value, n):
    ret = []
    for i in range(n):
        a = []
        for j in range(n):
            if i == j:
                a.append(float(value))
            else:
                a.append(0.0)
        ret.append(a)
    return ret

# Matrix multiplication
def mm(X, Y):
    result = zeroes(len(X), len(Y[0]))
    for i in range(len(X)):
       for j in range(len(Y[0])):
           for k in range(len(Y)):
               result[i][j] += X[i][k] * Y[k][j]
    return result
# Matrix addition
def ma(X, Y):
    result = []
    for i in range(len(X)):
        temp_row = []
        for j in range(len(X[i])):
            temp_row.append(X[i][j] + Y[i][j])
        result.append(temp_row)
    return result

def m_delta(X,Y):
    diff = []
    for i in range(len(X)):
        for j in range(len(X[0])):
            diff.append(X[i][j] - Y[i][j])
    return abs(sum(diff) / len(diff))

def asstet_matrix(a, b):
    if len(a) == len(b):
        for i in range(len(a)):
            if len(a[i]) == len(b[i]):
                for j in range(len(a)):
                    if a[i][j] != b[i][j]:
                        raise Exception("Assertion error!\n{}\n{}".format(a,b))
            else:
                raise Exception("Assertion error!\n{}\n{}".format(a,b))
    else:
        raise Exception("Assertion error!\n{}\n{}".format(a,b))

def test_mm():
    a = [[1, 2, 3], [4, 5, 6]]
    b = [[7, 8], [9, 10], [11, 12]]
    result = mm(a, b)
    ref = [[58, 64], [139, 154]]
    asstet_matrix(result, ref)
    print("test_mm: passed")

def test_ma():
    a = [[3, 4], [2, 1]]
    b = [[1, 5],[3, 7]]
    result = ma(a, b)
    ref = [[4, 9], [5, 8]]
    asstet_matrix(result, ref)
    print("test_ma: passed")


if __name__ == "__main__":
    test_mm()
    test_ma()