R version 2.7.0 (2008-04-22)
Copyright (C) 2008 The R Foundation for Statistical Computing
ISBN 3-900051-07-0

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> x <- c(-22,-31,-22,-26,-19,-20,-24,-29,-28,-31,-30,-32,-38,-43,-51,-43,-43,-42,-47,-45,-38,-46,-38,-32,-27,-26,-21,-23,-24,-17,-23,-16,-22,-26,-25,-21,-21,-18,-12,-19,-31,-38,-38,-32,-43,-33,-28,-25,-19,-20,-21,-19,-17,-16,-10,-16,-10,-8,-7,-15,-7,-6,-6,2,-4,-4,-8,-10,-16,-14,-30,-33)
> par3 = 'multiplicative'
> par2 = 'Triple'
> par1 = '12'
> #'GNU S' R Code compiled by R2WASP v. 1.0.44 ()
> #Author: Prof. Dr. P. Wessa
> #To cite this work: AUTHOR(S), (YEAR), YOUR SOFTWARE TITLE (vNUMBER) in Free Statistics Software (v$_version), Office for Research Development and Education, URL http://www.wessa.net/rwasp_YOURPAGE.wasp/
> #Source of accompanying publication: Office for Research, Development, and Education
> #Technical description: Write here your technical program description (don't use hard returns!)
> par1 <- as.numeric(par1)
> if (par2 == 'Single') K <- 1
> if (par2 == 'Double') K <- 2
> if (par2 == 'Triple') K <- par1
> nx <- length(x)
> nxmK <- nx - K
> x <- ts(x, frequency = par1)
> if (par2 == 'Single') fit <- HoltWinters(x, gamma=0, beta=0)
> if (par2 == 'Double') fit <- HoltWinters(x, gamma=0)
> if (par2 == 'Triple') fit <- HoltWinters(x, seasonal=par3)
Error in HoltWinters(x, seasonal = par3) : 
  data must be strictly non-negative for multiplicative Holt-Winters
Execution halted