Bug 16864 - nlme: lme gives incorrect answers without warning with redundant data
Summary: nlme: lme gives incorrect answers without warning with redundant data
Status: UNCONFIRMED
Alias: None
Product: R
Classification: Unclassified
Component: Analyses (show other bugs)
Version: R 3.2.4
Hardware: x86_64/x64/amd64 (64-bit) Linux
: P5 minor
Assignee: R-core
URL:
Depends on:
Blocks:
 
Reported: 2016-05-03 22:38 UTC by Jonathan Dushoff
Modified: 2016-05-03 22:38 UTC (History)
0 users

See Also:


Attachments
nlme analysis of redundant data, with noise titrated to near zero (797 bytes, text/x-r-source)
2016-05-03 22:38 UTC, Jonathan Dushoff
Details

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Description Jonathan Dushoff 2016-05-03 22:38:21 UTC
Created attachment 2072 [details]
nlme analysis of redundant data, with noise titrated to near zero

On certain pathological data sets, where the data is nearly redundant, lme returns nonsensical answers (which is understandable), but does so without producing any warnings (which is worrisome).

I would like to see warnings when I encounter singularities, so that I can be aware that results might not be reliable.

I attach a simple, complete, example. There is more discussion of the issue at https://htmlpreview.github.io/?https://github.com/dushoff/scratch/blob/master/nlme.html