小编Tom*_*ien的帖子

我一直在使用一段代码(基于此处给出的另一个问题的解决方案)来创建具有两个x轴的光谱数据图.第一个(底部)是频率单位,第二个(顶部)只是转换为波长单位(波长= 3E8 /频率).这很有效,直到我将MPL升级到1.4.2,之后上轴的值与下轴上的值相同(参见示例).

MWE(来自MPL邮件列表的精确副本)是:

from matplotlib.transforms import Transform, BlendedGenericTransform, IdentityTransform 
import matplotlib.pyplot as plt 
from mpl_toolkits.axes_grid.parasite_axes import SubplotHost 
import numpy as np 

c = 3.e2 

class Freq2WavelengthTransform(Transform): 
    input_dims = 1 
    output_dims = 1 
    is_separable = False 
    has_inverse = True 

    def transform(self, tr): 
        return c/tr 

    def inverted(self): 
        return Wavelength2FreqTransform() 


class Wavelength2FreqTransform(Freq2WavelengthTransform): 
    def inverted(self): 
        return Freq2WavelengthTransform() 

aux_trans = BlendedGenericTransform(Freq2WavelengthTransform(), 
IdentityTransform()) 

fig = plt.figure(2) 

ax_GHz = SubplotHost(fig, 1,1,1) 
fig.add_subplot(ax_GHz) 
ax_GHz.set_xlabel("Frequency (GHz)") 


xvals = np.arange(199.9, 999.9, 0.1) 
#make some test data 
data …