GetL {bcpa} R Documentation

## Obtain likelihood of gappy Gaussian time series

### Description

Obtain likelihood of gappy standardized Gaussian time series "x" sampled at times "t" given parameter "rho" (autocorrelation). Alternatively computes the charactersitic time scale "tau".

### Usage

```GetL(x, t, rho, tau = FALSE)
```

### Arguments

 `x` Time series `t` Sampling times `rho` Auto-correlation `tau` logical: Whether or not to compute characteristic time scale instead of rho.

### Value

Returns the log-likelihood of the data.

### Author(s)

Eliezer Gurarie

Core function of BCPA, used directly in `GetRho`

### Examples

```# create full time-series
rho <- 0.8
x.full <- arima.sim(1000, model=list(ar = rho))
t.full <- 1:1000

# subsample time series
keep <- sort(sample(1:1000, 200))
x <- x.full[keep]
t <- t.full[keep]
plot(t,x, type="l")

# sweep values of rho
rhos <- seq(0,.99,.01)
L <- rep(NA, length(rhos))
for(i in 1:length(rhos))
L[i] <- GetL(x,t,rhos[i])

# plot likelihood profile
plot(rhos, L, type="l")
abline(v = rhos[L == max(L)], lty=3, lwd=2)
abline(v = rho, lty=2, lwd=2)
legend("bottomleft", legend=c("true value","MLE"), lty=3:2, lwd=2)
```

[Package bcpa version 1.1 Index]