Python笔记 #21# DHNN

离散型hopfield神经网络。参考自http://web.cs.ucla.edu/~rosen/161/notes/hopfield.html实现的草稿版本：

# http://web.cs.ucla.edu/~rosen/161/notes/hopfield.html

attractors = np.array([[0, 1, 1, 0, 1], [1, 0, 1, 0, 1]])
print('attractors:\n', attractors)

weight_matrix = np.zeros((5, 5))
print('weight_matrix:\n', weight_matrix)
# 第一个向量表示第一个节点到各个节点的权值

# 初始化网络，权值是对称的，例如w12 = w21，而w11 w22都是0
# for i in range(len(weight_matrix)):
def reflect_about_the_diagonal(matrix):
    # 将矩阵上三角翻转拷贝到下三角
    matrix += matrix.T - np.diag(matrix.diagonal())

for attractor in attractors:
    temp_matrix = np.zeros((5, 5))
    for i in range(0, 4):
        for j in range(i + 1, 5):
            temp_matrix[i, j] = (2 * attractor[i] - 1) * (2 * attractor[j] - 1)
    weight_matrix += temp_matrix
    
reflect_about_the_diagonal(weight_matrix)
print('weight_matrix:\n', weight_matrix)

# print(weight_matrix[2].dot(attractors[0]))


# 类似于bp里的预测,som里的map
def xxxx(input_vector):
    vector = input_vector.copy()
    
    stable_state = False
    
    random_order = np.arange(len(attractors[0]))

    
    while not stable_state:
        # 生成一个随机序列，以随机的顺序更新节点
        np.random.shuffle(random_order)
        stable_state = True
        for i in random_order:
            original_value = vector[i]
            vector[i] = weight_matrix[i].dot(vector)
            if (vector[i] >= 0):
                vector[i] = 1
            else:
                vector[i] = 0
            if (vector[i] != original_value):
                print(i, "change ", original_value, '->', vector[i])
                stable_state = False
        
    return vector

x = [1, 1, 1, 1, 1]
print('test:', x, '->', xxxx(np.array(x)))