## Fast Computation of Moving Window Average

### Description

Compute moving window average of a time-series `x`.

### Usage

```windowSmooth(x, W, x.fs = 1)
```

### Arguments

 `x` A numeric vector. A time-series for which a moving window average is computed. `W` A numeric scalar. A length of a moving window, expressed in time (seconds). `x.fs` Frequency of a time-series `x`, expressed in a number of observations per second. Defaults to `1`.

### Details

Time-series frequency `x.fs` and a length of a moving window (expressed in time) `W` together determine `W.vl = round(W * x.fs)`, a length of a moving window expressed in a length of `x` vector object. Note: `W.vl` must be equal or greater than `3`.

• If `W.vl < 3` then an error is thrown.

• If `W.vl` is an even number then `(W.vl-1)` value is silently used instead as a length of a moving window expressed in `x` vector length.

### Value

A numeric vector. Moving window average of a time-series `x`. Note: head and tail of the output vector where the moving window is undefined are filled with `NA`.

### Examples

```## Time-series defined as a function f(x) = x
N <- 100
W  <- 20
x <- 1:N
x.smoothed <- windowSmooth(x, W)
plot(x, type = "l")
points(x.smoothed, col = "red")

## Time-series defined as a function f(x) = sin(x) + noise
N <-  1000
W  <- 100
x <- sin(seq(0, 4 * pi, length.out = N)) + rnorm(N, sd = 0.1)
x.smoothed <- windowSmooth(x, W)
plot(x, type = "l")
points(x.smoothed, col = "red")

```