envcpt-package: Detection of Structural Changes in Climate and Environment...

Description Details Author(s) References See Also Examples

Description

Tools for automatic model selection and diagnostics for Climate and Environmental data. In particular the envcpt() function does automatic model selection between a variety of trend, changepoint and autocorrelation models. The envcpt() function should be your first port of call.

Details

Package: EnvCpt
Type: Package
Version: 0.1.1
Date: 2016-10-11
License: GPL
LazyLoad: yes

Author(s)

Rebecca Killick <[email protected]>, Claudie Beaulieu <[email protected]>, Simon Taylor <[email protected]>

Maintainer: Rebecca Killick <[email protected]>

References

PELT Algorithm: Killick R, Fearnhead P, Eckley IA (2012) Optimal detection of changepoints with a linear computational cost, JASA 107(500), 1590–1598

See Also

envcpt,AIC.envcpt,plot.envcpt

Examples

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## Not run: 
set.seed(1)
x=c(rnorm(100,0,1),rnorm(100,5,1))
out=envcpt(x) # run the 8 models with default values
out[[1]] # first row is twice the negative log-likelihood for each model
         # second row is the number of parameters
AIC(out) # returns AIC for each model.
which.min(AIC(out)) # gives meancpt (model 2) as the best model fit.
out[[3]] # gives the model fit for the meancpt model.
plot(out,type='fit') # plots the fits
plot(out,type="aic") # plots the aic values

set.seed(10)
x=c(0.01*(1:100),1.5-0.02*((101:250)-101))+rnorm(250,0,0.2)
out=envcpt(x,minseglen=10) # run the 8 models with a minimum of 10 observations between changes
AIC(out) # returns the AIC for each model
which.min(AIC(out)) # gives trendcpt (model 6) as the best model fit.
out[[7]] # gives the model fit for the trendcpt model.
plot(out,type='fit') # plots the fits
plot(out,type="aic") # plots the aic values

set.seed(100)
x=arima.sim(model=list(ar=0.8),n=100)+5
out=envcpt(x) # run the 8 models with 
AIC(out) # returns the AIC for each model
which.min(AIC(out)) # gives trendar (model 7) as the best model fit.
out[[7]] # gives the model fit for the trendar model. Notice that the trend is tiny but does 
# produce a significantly better fit than the meanar model.
plot(out,type='fit') # plots the fits
plot(out,type="aic") # plots the aic values

## End(Not run)

EnvCpt documentation built on May 29, 2017, 11:33 p.m.