dSTEM (version 2.0-1)

cpTest: Multiple testing of change points for kernel smoothed data

Description

Multiple testing of change points for kernel smoothed data

Usage

cpTest(
  x,
  order,
  alpha,
  gamma,
  sigma,
  breaks,
  slope,
  untest,
  nu,
  is.constant,
  margin
)

Value

a list of estimated change-point locations and threshold for p-value

Arguments

x

vector of kernel smoothed data

order

order of derivative of data

alpha

global significant level

gamma

bandwidth of Gaussian kernel

sigma

standard deviation of kernel smoothed noise

breaks

vector of rough estimate of change-point locations, only required when order is 1.

slope

vector of rough estimate of slopes associated with breaks, only required when order is 1.

untest

vector of locations unnecessary to test

nu

standard deviation of Gaussian kernel used to generate autocorrelated Gaussian noise, it is 0 if the noise is Gaussian white noise.

is.constant

logical value indicating if the signal is piecewise constant, if TRUE, breaks and slope are not necessary.

margin

length of one period of data x

Examples

## piecewise linear signal
l = 1200
h = seq(150,by=150,length.out=6)
jump = rep(0,7)
beta1 = c(2,-1,2.5,-3,-0.2,2.5)/50
beta1 = c(beta1,-sum(beta1*(c(h[1],diff(h))))/(l-tail(h,1)))
signal = gen.signal(l,h,jump,beta1)
noise = rnorm(length(signal),0,2)
gamma = 25
sdata = smth.gau(signal+noise,gamma)
ddy = diff(sdata,differences=2)
model2 = cpTest(x=ddy,order=2,gamma=gamma,alpha=0.05)
## piecewise constant
l = 1200
h = seq(150,by=150,length.out=6)
jump = c(0,1.5,2,2.2,1.8,2,1.5)
beta1 = rep(0,length(h)+1)
signal = gen.signal(l,h,jump,beta1)
noise = rnorm(length(signal),0,1)
gamma = 25
sdata = smth.gau(signal+noise,gamma)
dy = diff(sdata)
model1 = cpTest(x=dy,order=1,alpha=0.05,gamma=gamma,is.constant=TRUE)
## piecewise linear with jump
l = 1200
h = seq(150,by=150,length.out=6)
jump = c(0,1.5,2,2.2,1.8,2,1.5)*3
beta1 = c(2,-1,2.5,-3,-0.2,2.5,-0.5)/50
signal = gen.signal(l=l,h=h,jump=jump,b1=beta1)
noise = rnorm(length(signal),0,1)
gamma = 25
sdata = smth.gau(signal+noise,gamma)
dy = diff(sdata)
ddy = diff(sdata,differences=2)
model2 = cpTest(x=ddy,order=2,gamma=gamma,alpha=0.1)
breaks = est.pair(vall=model2$vall,peak=model2$peak,gamma=gamma)$cp
slope = est.slope(x=(signal+noise),breaks=breaks)