px.line erratic and wrong for large x value ranges
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- Dominant language
- Python
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Description
Problem
Plotting a straight line from ($-X$, 0) to ($+X$, 1) for various (large) $X$ within a much smaller window results in wrong and inconsistent behavior, as demonstrated in below minimum non-working examples (using a Jupyter notebook with plotly.js v2.27.0).
I doubt that this behavior can be explained by intrinsic rounding problems, since
>>> np.interp([-0.1,0.1],[-1e17,+1e17],[0,1])
array([0.5, 0.5])
>>> np.interp([-0.1,0.1],[-1e18,+1e18],[0,1])
array([0.5, 0.5])
Examples
Data frame
df = pd.DataFrame(dict(x=[-1e17,+1e17,-1e18,+1e18],
y=[0,1,0,1],
xlimit=['±1e17','±1e17','±1e18','±1e18']))
Very tight plotting range (symmetric 0.1)
fig = px.line(df,x='x',y='y',color='xlimit',
range_x=[-.1,.1],
range_y=[0.4,0.6],
width=400,
height=400,)
fig.update_traces(opacity=0.5)
fig.show()
Slightly wider plotting range (symmetric 0.3)
fig = px.line(df,x='x',y='y',color='xlimit',
range_x=[-.3,.3],
range_y=[0.4,0.6],
width=400,
height=400,)
fig.update_traces(opacity=0.5)
fig.show()
Another plotting range (symmetric 1)
fig = px.line(df,x='x',y='y',color='xlimit',
range_x=[-1,1],
range_y=[0.4,0.6],
width=400,
height=400,)
fig.update_traces(opacity=0.5)
fig.show()
Another even wider plotting range (symmetric 3)
fig = px.line(df,x='x',y='y',color='xlimit',
range_x=[-3,3],
range_y=[0.4,0.6],
width=400,
height=400,)
fig.update_traces(opacity=0.5)
fig.show()
Apparently wide enough plotting range (symmetric 3.2)
fig = px.line(df,x='x',y='y',color='xlimit',
range_x=[-3.2,3.2],
range_y=[0.4,0.6],
width=400,
height=400,)
fig.update_traces(opacity=0.5)
fig.show()
As far as my tests go, for any range_x that is wider than about ±3, the plotting is rendered correctly:
fig = px.line(df,x='x',y='y',color='xlimit',
range_x=[-1e17,1e17],
range_y=[0,1],
width=400,
height=400,)
fig.update_traces(opacity=0.5)
fig.show()
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the issue in a Jupyter notebook using px.line with the supplied DataFrame, narrow range_x values, and plotly.js v2.27.0. Compare the rendered lines across the example ranges and trace whether the behavior originates in the plotly.py px.line path or the plotly.js rendering; done means the large-range lines render consistently in the provided cases.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, jupyter-notebook, python
- Domain
- data-visualization
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100