多进程使用matplotlib.pyplot绘heatmap（多线程不可以）

8_15/l_eye/2732.png -20.5773 -5.17769 -3.34583 21.5859
9_13_1/l_eye/1211.png -10.1145 34.9928 -38.2122 -26.3371
8_20/l_eye/5966.png -44.0264 50.2898 63.5838 -49.1353
8_13/l_eye/8780.png -16.9358 50.4528 -44.2617 -57.1462
9_16_2/l_eye/5370.png -21.2264 17.0589 4.33619 -20.3562
9_15_1/l_eye/66.png 40.5758 -21.0923 12.0032 40.8452
8_13/l_eye/6664.png 51.0789 55.3987 -67.2433 -79.1243
9_15_2/l_eye/4429.png 16.958 30.0386 -24.5935 -26.4802
8_21/l_eye/2579.png -20.619 4.7845 21.9891 27.529
8_21/l_eye/8464.png -36.8559 54.4664 -32.1576 -67.6335
8_21/l_eye/359.png 20.9732 2.25414 -3.88966 41.175
9_16_2/l_eye/3065.png 7.16623 43.091 35.9651 -28.4994
9_14_2/l_eye/1961.png 33.3302 28.3553 22.7904 -28.5209
9_16_1/l_eye/2038.png 56.9721 24.6518 -23.5831 -39.2209

#!/usr/bin/python
# -*- encoding: utf-8 -*-import numpy as np
from matplotlib import pyplot as plt#import thread
#from threading import Thread
from multiprocessing import Processimport pdbdef generate_heat_array(is_test=0):
#pdb.set_trace()
if is_test==1:
# gussian distribution
mean = [0,0]
cov = [[0,1],[1,0]]
x, y = np.random.multivariate_normal(mean, cov, 10000).T
show_heat_map(x,y)
return x_head=[]
y_head=[]
x_gaze=[]
y_gaze=[]
for line in open('train.txt'):
split_data=line.split()
x_head.append(float(split_data[1]))
y_head.append(float(split_data[2]))
x_gaze.append(float(split_data[3]))
y_gaze.append(float(split_data[4])) #用thread库实现多线程
#由于主线程退出时，子线程自动中止，因此需要join；由于thread库未提供join方法，所以需要自己手动实现。
#thread.start_new_thread(show_heat_map,(x_head,y_head,1))
#thread.start_new_thread(show_heat_map,(x_gaze,y_gaze,2)) #用threading库实现多线程
#threading库提供了join方法。但是由于matplotlib.pyplot中的方法都是全局的，因此用多线程绘图会有错误：RuntimeError: main thread is not in main loop
#head_thread=Thread(target=show_heat_map, args=(x_head,y_head,1,))
#gaze_thread=Thread(target=show_heat_map,args=(x_gaze,y_gaze,2,))
#head_thread.start()
#gaze_thread.start()
#head_thread.join()
#gaze_thread.join() #用multiprocessing实现多进程
head_process=Process(target=show_heat_map,args=(x_head,y_head,1,))
gaze_process=Process(target=show_heat_map,args=(x_gaze,y_gaze,2,))
head_process.start()
gaze_process.start()
head_process.join()
gaze_process.join()def show_heat_map(x,y,n):
#pdb.set_trace()
fig=plt.figure(n)
plt.hist2d(x,y,bins=100)
plt.grid(True)
plt.colorbar()
#fig.savefig('%02i.png'%n)
plt.show()if __name__=='__main__':
generate_heat_array(0)