Sankey node x and y positions ignored if node is empty

Consider the next example

import numpy as np
import plotly.graph_objects as go

def plot_sankey(source, target, value, labels):
    "From <https://plotly.com/python/sankey-diagram/>"
    fig = go.Figure(data=[go.Sankey(
        arrangement = "perpendicular",
        node = dict(
          pad = 15,
          thickness = 20,
          line = dict(color = "black", width = 0.5),
          label = labels,
          color = "red",
        ),
        link = dict(
          source = source, # indices correspond to labels, eg A1, A2, A1, B1, ...
          target = target,
          value = value
        ))])

    return fig


source = np.expand_dims(range(0, 25), axis=1).repeat(5, axis=1).flatten()
target = np.array(range(5, 30)).reshape(5, -1).repeat(5, axis=0).flatten()

value_not_so_sparse = [0, 7, 1, 2, 0, 5, 241, 5, 255, 6, 0, 11, 2, 8, 0, 10, 221, 9, 203, 2, 0, 7, 0, 5, 0, 0, 9, 0, 6, 0, 6, 251, 9, 217, 4, 0, 7, 1, 9, 0, 6, 220, 7, 239, 1, 0, 5, 1, 2, 0, 0, 6, 0, 6, 0, 2, 231, 14, 240, 5, 0, 9, 0, 9, 0, 6, 214, 9, 242, 2, 0, 3, 0, 2, 0, 0, 1, 1, 4, 2, 5, 241, 5, 211, 1, 1, 12, 0, 9, 1, 3, 230, 19, 243, 4, 0, 2, 0, 5, 0, 0, 4, 0, 5, 0, 8, 217, 13, 245, 3, 0, 10, 0, 15, 0, 8, 222, 8, 231, 3, 0, 4, 0, 4, 0]

value_sparse = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 274, 460, 266, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 142, 129, 3, 0, 0, 0, 103, 242, 115, 0, 0, 0, 18, 126, 122, 0, 0, 0, 0, 0, 140, 2, 0, 0, 0, 106, 116, 10, 0, 0, 0, 64, 124, 75, 0, 0, 0, 6, 118, 117, 0, 0, 0, 1, 121, 242, 4, 0, 0, 0, 96, 82, 4, 0, 0, 0, 38, 65, 37, 0, 0, 0, 9, 87, 98, 0, 0, 0, 4, 234, 333, 5, 0, 0, 0, 58, 62, 4, 0, 0, 0, 15, 36, 27, 0, 0, 0, 3, 75, 50, 0, 0, 0, 13, 319]

labels = []
# because labels could not repeat at different time points
for i in range(6):
    labels.extend([f'{j}_{i}' for j in [1, 2, 3, 4, 5]])

# True
len(source) == len(target) == len(value_not_so_sparse) == len(value_sparse)

Plot sankey where all nodes are present:

fig = plot_sankey(source, target, value_not_so_sparse, labels)
fig.show()

Now try to rearrange nodes:

fig.data[0].node.x = np.linspace(1e-09, 1, 6).repeat(5)
fig.data[0].node.y = np.expand_dims(np.linspace(1e-09, 1, 5), axis=1).repeat(6, axis=1).T.flatten()
fig.show()

Everything works. Not without crotches (https://github.com/plotly/plotly.py/issues/3002, https://github.com/plotly/plotly.py/issues/1732), but works.

Now try plot where some nodes are missing, but we still want to arrange them:

fig = plot_sankey(source, target, value_sparse, labels)
fig.show()

Now arrange should work still because we have the same target, source, labels ans len(values):

fig.data[0].node.x = np.linspace(1e-09, 1, 6).repeat(5)
fig.data[0].node.y = np.expand_dims(np.linspace(1e-09, 1, 5), axis=1).repeat(6, axis=1).T.flatten()
fig.show()

It counts only non-empty nodes

Not sure if it is not plotly.js problem

Chạy ví dụ Sankey bằng Python với value_sparse, sau đó gán các mảng node.x và node.y được hiển thị trước khi hiển thị biểu đồ. So sánh kết quả với trường hợp value_not_so_sparse; hoàn thành có nghĩa là các node được định vị rõ ràng vẫn giữ nguyên vị trí được yêu cầu ngay cả khi một số node có các liên kết có giá trị bằng 0.