Find zero crossings of a vector, i.e., indices when the numeric variable
crosses 0.

## Arguments

## Value

Vector of zero crossings.

## See also

Based on the `uniroot.all`

function from the rootSolve package.

## Examples

```
x <- sin(seq(0, 4 * pi, length.out = 100))
plot(x)
zero_crossings(x)
#> [1] 1.00000 25.74975 50.50000 75.25025
```