plotly.py: Carpet plot 4 variable axis problem

Question

I am trying to use plotly.py in python to duplicate the 4 variable carpet plot in this link titled "A four-variable carpet plot showing interpolation."

I have noticed two things. First, the length of arrays a and b must be the same. Ok, I can live with that. More importantly, I seem to need to switch the arguments when I call the carpet plot function. I don't understand what I am doing wrong, but if I call

 fig = go.Figure(go.Carpet(a=b, b=a, ...

then it work as desired. But why are my a and b vectors reversed...

Here is the entire working example:

 import plotly.graph_objects as go import numpy as np na = 7 nb = 7 x = np.ndarray(shape=(na, nb)) y = np.ndarray(shape=(na, nb)) a = np.array(range(4,4+na)) b = np.array(range(10,10+nb)) #print(x) for i in range(0,na): for j in range(0,nb): x[i,j] = np.sqrt(a[i] * b[j]) y[i,j] = np.sqrt(b[j])**3 / a[i] print(a[i], b[j], x[i,j], y[i,j]) print('a=',a) print('b=',b) print(x) fig = go.Figure(go.Carpet(a=b, b=a, x=x, y=y, aaxis = dict( tickprefix = 'b=', ticksuffix = 'm', smoothing = 1, minorgridcount = 9, minorgridwidth = 0.6, minorgridcolor = 'gray', gridcolor = 'black', color = 'blue' ), baxis = dict( tickprefix = 'a=', ticksuffix = 'Pa', smoothing = 1, minorgridcount = 9, minorgridwidth = 0.6, minorgridcolor = 'gray', gridcolor = 'black', color = 'blue' ) )) fig.show()

Why must I send a=b and b=a?

Why does the code fail if na?= nb?

Thanks!