[Rd] bug in loess (PR#611)

Prof Brian D Ripley ripley@stats.ox.ac.uk
Wed, 19 Jul 2000 17:44:33 +0100 (BST)


On Wed, 19 Jul 2000 hdrees@statlab.uni-heidelberg.de wrote:

> Full_Name: Holger Drees
> Version: 1.0.0-1
> OS: Windows NT 4.0/Linux Suse 6.3
> Submission from: (NULL) (129.206.113.204)
> 
> 
> After typing the commands
> 
> x <- seq(0,1,by=0.01)
> y <- sin(6*x)+rnorm(101)
> regtest <- loess(y~x,degree=1,surface="direct",family="symmetric")
> 
> regtest$fitted equals NULL. Moreover,
> 
> y-regtest$residuals
> 
> and 
> 
> predict.loess(regtest,x)
> 
> give different values, though both are supposed to give the vector of fitted
> values.
> The latter is the same for both choices of family ("gaussian" and "symmetric").
> This holds true for both the WINDOWS and LINUX SUSE 6.3 implementation. (Splus
> yields the 
> correct results.) This effect occurs only with the option surface="direct".

Since you have clearly looked into this, could you please provide a patch
which gives the correct answers.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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