python matplot 绘图出现以下错误怎么办？

import math
import matplotlib.pyplot as plt
import numpy as np


D = 100
R = 10
d = 25
ts = 1


def f(t):
    return (R / d) * math.erfc((d - R) / math.sqrt(4 * D * t))


def p(k, ts):
    return f((k + 1) * ts) - f(k * ts)


x = np.linspace(1, 20, 20)
y = p(x, ts)

plt.xlabel("N")
plt.ylabel("P")

plt.plot(x, y)
plt.show()

Traceback (most recent call last):
File "C:/Users/ZJUT/PycharmProjects/test/graph.py", line 21, in
y = p(x, ts)
File "C:/Users/ZJUT/PycharmProjects/test/graph.py", line 17, in p
return f((k + 1) * ts) - f(k * ts)
File "C:/Users/ZJUT/PycharmProjects/test/graph.py", line 13, in f
return (R / d) * math.erfc((d - R) / math.sqrt(4 * D * t))
TypeError: only size-1 arrays can be converted to Python scalars

https://www.cnblogs.com/liangliangzz/p/10242858.html