parma_ident: Identification of PC-T structure

In perARMA: Periodic Time Series Analysis

Identification of PC-T structure

Description

Procedure parma_ident utilizes a collection of procedures (functions) that together provide identification of PC structure in the series and saves results in the 'ident.txt' file, which is located in the working directory. This procedure could be applied to the original time series x or to the residuals of fitted PARMA models to characterize the goodness of fit.

Usage

parma_ident(x, T_t, missval, datastr, ...)

Arguments

x	input time series.
T_t	period of PC-T structure.
missval	notation for missing values.
datastr	string name of data for printing.
...	other arguments: outdir is string name of the directory in which file 'ident.txt' with results returned by parma_ident procedure will be saved, details should be equal to 1 to print all details. By default these parameters are fixed to outdir='IDENT_OUT', details=1.

Details

Procedure parma_ident provides a universal method for analyzing series or residuals. It calls following procedures: permest, persigest, peracf, Bcoeff, Bcoeffa, perpacf, ppfcoeffab, ppfplot, acfpacf.

Value

procedure returns list of values:

pmean	periodic mean values,
xd	series after removing periodic mean,
pstd	periodic standard deviations values,
xn	series obtained after removing periodic mean and divided by periodic standard deviations,

as well as a text file 'ident.txt' containing all the textual output generated in the running of parma_ident.

Author(s)

Harry Hurd

References

Hurd, H. L., Miamee, A. G., (2007), Periodically Correlated Random Sequences: Spectral Theory and Practice, Wiley InterScience.

Examples

############### PC-T series simulation
T=12
nlen=480
descriptor='PARMA(2,1) periodic phis all del =1'
p=2
 a=matrix(0,T,p)
q=1
 b=matrix(0,T,q)
a[1,1]=.8                 
a[2,1]=.3                                                                
a[1,2]=-.9  
             
phia<-ab2phth(a) 
phi0=phia$phi            
phi0=as.matrix(phi0)       
      
b[1,1]=-.7	          
b[2,1]=-.6                  
thetab<-ab2phth(b)       
theta0=thetab$phi  
theta0=as.matrix(theta0) 
del0=matrix(1,T,1)        

makeparma_out<-makeparma(nlen,phi0,theta0,del0)                        
y=makeparma_out$y

############### parma_ident use

parma_ident(t(y),T,NaN,descriptor,outdir=tempdir())

perARMA documentation built on Nov. 17, 2023, 9:06 a.m.