transform `x`

either via the logit, or inverse logit.

## Details

The logit and inverse logit functions are part of R via the logistic distribution functions in the stats package. Quoting from the documentation for the logistic distribution

"`qlogis(p)`

is the same as the `logit`

function, ```
logit(p) =
log(p/1-p)
```

, and `plogis(x)`

has consequently been called the 'inverse
logit'."

See the examples for benchmarking these functions. The `logit`

and
`invlogit`

functions are faster than the `qlogis`

and `plogis`

functions.

## Examples

```
library(rbenchmark)
# compare logit to qlogis
p <- runif(1e5)
identical(logit(p), qlogis(p))
#> [1] TRUE
if (FALSE) {
rbenchmark::benchmark(logit(p), qlogis(p))
}
# compare invlogit to plogis
x <- runif(1e5, -1000, 1000)
identical(invlogit(x), plogis(x))
#> [1] TRUE
if (FALSE) {
rbenchmark::benchmark(invlogit(x), plogis(x))
}
```