numpy / numpy/numpy

BUG: np.interp(nan, x, y) doesn't return nan when len(x)=1

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00 - Bug 54 - Needs decision
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Python
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Description

Reproducing code example:
import numpy as np
np.interp(np.nan, [1], [2])

returns 2.0 while nan is expected.

It returns nan correctly when len(x) > 1

np.interp(np.nan, [1, 1], [2, 2])

My numpy version: 1.15.3

Related issue: https://github.com/numpy/numpy/issues/605

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Research direction

Start by running the reported np.interp(np.nan, [1], [2]) example and compare it with the len(x) > 1 case. Trace the np.interp entry point to identify why the single-element input returns 2.0, then add or update coverage for the expected nan result and run the relevant NumPy tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
data
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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