无法对 numpy 阵列进行切片

Question

import numpy as np

n = int(input("Enter number of equations: "))
# Initialize matrix
print("Enter the values row-wise with the solution matrix of the coefficient matrix: ")

# For user input
a = np.array([[float(x) for x in input().split()] for y in range(n)])
b = np.array([float(y) for y in input().split()])[np.newaxis]
n = np.size(b)
b = b.T
sol = []
for i in range(n):
    sol = np.concatenate((a, b), axis=1)
    print(sol.round(decimals=4))
    for j in range(i+1, n):
        r = a[j][i] / a[i][i]
        a[j, :] = a[j, :] - (r * a[i, :])
        b[j] = b[j] - (r * b[i])
# Error part 
z = np.zeros((1, 3))
print(z)
for k in range(n-1, -1, -1):
    z[0, k] = (b[k] - (z[0, k] * a[k, k:])) / a[k, k]

print(z)

错误追溯：

TypeError: only size-1 arrays can be converted to Python scalars

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:/Users/Rohit Rasam/Python Programs/NMO/GaussElimination.py", line 24, in <module>
    z[0, k] = (b[k] - (z[0, k] * a[k, k:])) / a[k, k]
ValueError: setting an array element with a sequence.

Answer 1

在行

z[0, k] = (b[k] - (z[0, k] * a[k, k:])) / a[k, k]

你的右手边是一个数组，左手边是一个数组的单个元素。 您正在尝试将数组分配给引发错误的单个元素。 要么将左侧也更改为数组，要么将右侧更改为元素而不是数组。