Generate basis matrix for a periodic B-spline using `pbs::pbs()`

.

## Arguments

- x
Values of the predictor variable.

- period
Period for the predictor variable.

- nKnots
Number of internal knots.

- intercept
If

`TRUE`

, a column of ones will be included in the basis.

## Examples

```
b = getSplineBasis(seq(0, 20, 4), period = 24, nKnots = 3, intercept = FALSE)
```