View source: R/CWindowCluster.R

CWindowCluster | R Documentation |

Cluster time series at a window level, based on Algorithm 2 of \insertCiteCiampi_etal_2010;textualfuntimes.

```
CWindowCluster(
X,
Alpha = NULL,
Beta = NULL,
Delta = NULL,
Theta = 0.8,
p,
w,
s,
Epsilon = 1
)
```

`X` |
a matrix of time series observed within a slide (time series in columns). |

`Alpha` |
lower limit of the time-series domain,
passed to |

`Beta` |
upper limit of the time-series domain passed to |

`Delta` |
closeness parameter passed to |

`Theta` |
connectivity parameter passed to |

`p` |
number of layers (time-series observations) in each slide. |

`w` |
number of slides in each window. |

`s` |
step to shift a window, calculated in the number of slides. The recommended
values are 1 (overlapping windows) or equal to |

`Epsilon` |
a real value in |

This is the upper-level function for time series clustering. It exploits
the function `CSlideCluster`

to cluster time series within each slide
based on closeness and homogeneity measures. Then, it uses slide-level cluster
assignments to cluster time series within each window.

The total length of time series (number of levels, i.e., `nrow(X)`

)
should be divisible by `p`

.

A vector (if `X`

contains only one window) or matrix with cluster
labels for each time series (columns) and window (rows).

Vyacheslav Lyubchich

`CSlideCluster`

, `CWindowCluster`

,
and `BICC`

```
#For example, weekly data come in slides of 4 weeks
p <- 4 #number of layers in each slide (data come in a slide)
#We want to analyze the trend clusters within a window of 1 year
w <- 13 #number of slides in each window
s <- w #step to shift a window
#Simulate 26 autoregressive time series with two years of weekly data (52*2 weeks),
#with a 'burn-in' period of 300.
N <- 26
T <- 2*p*w
set.seed(123)
phi <- c(0.5) #parameter of autoregression
X <- sapply(1:N, function(x) arima.sim(n = T + 300,
list(order = c(length(phi), 0, 0), ar = phi)))[301:(T + 300),]
colnames(X) <- paste("TS", c(1:dim(X)[2]), sep = "")
tmp <- CWindowCluster(X, Delta = NULL, Theta = 0.8, p = p, w = w, s = s, Epsilon = 1)
#Time series were simulated with the same parameters, but based on the clustering parameters,
#not all time series join the same cluster. We can plot the main cluster for each window, and
#time series out of the cluster:
par(mfrow = c(2, 2))
ts.plot(X[c(1:(p*w)), tmp[1,] == 1], ylim = c(-4, 4),
main = "Time series cluster 1 in window 1")
ts.plot(X[c(1:(p*w)), tmp[1,] != 1], ylim = c(-4, 4),
main = "The rest of the time series in window 1")
ts.plot(X[c(1:(p*w)) + s*p, tmp[2,] == 1], ylim = c(-4, 4),
main = "Time series cluster 1 in window 2")
ts.plot(X[c(1:(p*w)) + s*p, tmp[2,] != 1], ylim = c(-4, 4),
main = "The rest of the time series in window 2")
```

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