scikit-learn / scikit-learn/scikit-learn

Bad error messages in ClassifierChain on multioutput multiclass

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module:multioutput
Dominant language
Python
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Description

trying to run classifier chain on a multiclass problem with a reshaped y (which is interpreted as multioutput multiclass) doesn't work (see #9245), which is fine. But the error messages are really bad making it hard to understand what's going on.

We should detect that we're trying to do multioutput multiclass instead of multilabel and give an informative error.

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Research direction

Start at the ClassifierChain entry point and reproduce the reported case with a multiclass target reshaped into multioutput form. Trace the validation that produces the current error and update it so multioutput multiclass is identified distinctly from multilabel, with an informative error message as the completion criterion.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
machine-learning
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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