用户鼠标在积分限制图上的输入 - python

Question

>我有一个分布，我希望通过用户在分布图上单击鼠标选择的自定义范围进行积分。

import numpy as np
import matplotlib.pyplot as plt
from scipy import stats
from scipy.integrate import trapz
# Probability Density Function
pdf = stats.norm.pdf
#adjust the location and scale of the distribution
loc1, scale1, size1 = (20, 1.5, 500)
loc2, scale2, size2 = (28, 2.5, 500)
# Probability Density Function
pdf = stats.norm.pdf
x2 = np.concatenate([np.random.normal(loc=loc1, scale=scale1, size=size1),np.random.normal(loc=loc2, scale=scale2, size=size2)])
x_eval = np.linspace(x2.min() - 1, x2.max() + 1, 1000)
bimodal_pdf = pdf(x_eval, loc=loc1, scale=scale1) * float(size1) / x2.size + pdf(x_eval, loc=loc2, scale=scale2) * float(size2) / x2.size
plt.figure()
plt.plot(x_eval,bimodal_pdf)
plt.show()

在这一点上，我希望能够选择 x 的下限和上限，在此下限和上限上将计算 y 的积分。

即。

a = User mouse click x position 1
b = User mouse click x position 2
area = trapz(y[a,b], x[a:b])

print 'the area under curve between x1 and x2 = ' + str(area)

Answer 1

如果您想要最简单的选项，请使用 point1, point2 = plt.ginput(2) 。

point1和point2将是 x，y 的元组，因此您希望在示例中使用a, b = point1[0], point2[0]元组。

举个简单的例子：

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.set(title='Click Twice', xlabel='X', ylabel='Y')
point1, point2 = fig.ginput(2) # Or equivalently, "plt.ginput"
ax.autoscale(False)
ax.axvspan(point1[0], point2[0], color='red', alpha=0.5)
fig.canvas.draw()
plt.show()