使用multiprocessing.pool的空白图

Question

我有一个列表，我映射到一个函数使用multiprocessing.pool.starmap。代码看起来像这样:

def plot_data(actual, predicted, ax):
if ax is None:
ax = plt.gca()
area, kde1_x, kde2_x, idx, x = distribution_intersection_area(actual, predicted)
ax.plot(x, kde1_x, color='dodgerblue',label='original', linewidth=2)
ax.plot(x, kde2_x, color='orangered', label='forecasted', linewidth=2)
ax.fill_between(x, np.minimum(kde1_x, kde2_x), 0,color='lime', alpha=0.3,,label='intersection') 
ax.plot(x[idx], kde2_x[idx], 'ko')
handles, labels = ax.get_legend_handles_labels()
labels[2] += f': {area * 100:.1f}%'
ax.legend(handles, labels)

def do_something(col, k, rows, fig):
ax = fig.add_subplot(rows, display_cols, position[k])
plot_data(actual,predicted)
annot = 'my plot'
ax.set_title(annot)
rows = 10
fig = plt.figure(figsize=(30, 4 * rows))
fig.subplots_adjust(hspace=0.3, wspace=0.2)
actuals = [1,2,3,4,5,6] # Its actually a long list of floats
predicted = [10,20,30,40,50,60] # list of predicted values

loop_list= ['col1','col2','col3']
with Pool(processes=None) as pool:
my_args = [(col, k, rows, fig) for k, col in enumerate(loop_list)]
results = pool.starmap(do_something, my_args)

然后我尝试将情节保存为:

try:
plt.suptitle('my calculation status', y=0.94, fontsize=18)
plt.savefig('./outputs/test.jpg',dpi = 150)
plt.show
except Exception as e:
print(e)
plt.show()

我也试过使用:

try:
plt.show()
fig.savefig('./outputs/line_plot.png', dpi=100)
except Exception as e:
print(e)

但是我得到的是一片空白。这是一张白色的图片，只有文字'my calculation status'

有人能帮忙吗?

Answer 1

我最终使用自定义栅格化函数:

def rasterize(fig : matplotlib.figure):
buf = io.BytesIO()
fig.savefig(buf, format='png', bbox_inches='tight')
buf.seek(0)
rasterized_plot = deepcopy(Image.open(buf))
buf.close()

return rasterized_plot

并使用它将栅格化的绘图保存在数组中，并在öater上循环绘制:

pil_img = rasterize(fig)
plt.close()
return pil_img 
for ax, rastered in zip(axes.ravel(), drift_plots):
ax.imshow(rastered)
plt.subplots_adjust(hspace=0.3, wspace=0.2)
plt.suptitle(drift_stat, y=0.94, fontsize=18)