Question

我想在矩阵的数组中迭代地相乘

matrix[0] = [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]
matrix[1] = [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]
matrix[3] = [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]
matrix[4] = [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]
matrix[5] = [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]
matrix[6] = [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]

乘法矩阵[0]和矩阵[1]的结果将乘以下一个矩阵矩阵[3]。这个结果将再次与下一个结果相乘。这个过程应该按顺序进行。任何想法或解决方案？感谢

Answer 1

您所描述的是reduce操作：

Python 2.7: built-in functions: reduce

假设您已定义此矩阵乘法函数：

def multiply(a, b):
    num_r, num_c, num_i = len(a), len(b[0]), len(a[0])
    m = [num_c * [None] for r in range(num_r)]
    for r in range(num_r):
        for c in range(num_c):
            x = 0
            for i in range(num_i):
                x += a[r][i] * b[i][c]
            m[r][c] = x
    return m

你有这个矩阵列表：

matrices = [[[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]],
            [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]],
            [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]],
            [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]],
            [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]],
            [[1,2,3,4], [1,2,3,4], [1,2,3,4], [1,2,3,4]]]

现在，您可以将一个矩阵按顺序乘以reduce：

print reduce(multiply, matrices)

Answer 2

我明白了（操作*是矩阵乘法过程的简化）：

for i in range(6):
    A = matrix[i]
    B = matrix[i+1]
    C = A * B
    matrix [i+1] = C
return C

让我知道是否有其他更好的方法来做到这一点。感谢

在矩阵乘法python语言中删除和插入值

2 个答案: