Question

我一直试图弄清楚如何使用此功能，但似乎无法获得x输入来执行任何操作。每当我输入x的数字值时，它就会告诉我由于“大小”问题而无法使用。

我该怎么办？

import numpy as np
from scipy.sparse import diags, kron, identity
from scipy.sparse.linalg import inv
import matplotlib.pyplot as plt

def laplacian_1D(x):
    """Construct the 1D Laplacian matrix on the domain defined by x. Note that
    we assume a constant spacing.

    Parameters
    ----------
    x : array-like, shape (nx, )
        One dimensional mesh.

    Returns
    -------
    A : scipy sparse matrix, shape (nx, nx)
        Laplacian matrix.

    """

    # -->
    n = x.size
    # -->
    dx = x[1]-x[0]

    # -->
    d2 = [np.ones(n-1), -2*np.ones(n), np.ones(n-1)]

    # -->
    A = diags(d2, [-1, 0, 1]) / dx**2

    return A


print(laplacian_1D(10))

读取错误

Traceback (most recent call last):
  File "C:/Users/Andrew/PycharmProjects/ENSAM/Math/Exercise_1.py", line 52, in <module>
    print(laplacian_1D(10))
  File "C:/Users/Andrew/PycharmProjects/ENSAM/Math/Exercise_1.py", line 23, in laplacian_1D
    n = x.size
AttributeError: 'int' object has no attribute 'size'

Answer 1

如参数说明中所述，该函数希望获得一个numpy数组或一个列表作为参数。例如，调用laplacian_1D(x = np.arange(10))将返回形状为（10,10）的拉普拉斯矩阵。注意，在函数中使用x的唯一方法是确定输出矩阵的大小和dx值。后者告诉您x应该是其元素值递增的列表。

如何从函数获取矩阵输出？

1 个答案: