This function returns TRUE for <phinterval> vectors and returns
FALSE otherwise.
Examples
is_phinterval(phinterval())
#> [1] TRUE
is_phinterval(interval())
#> [1] FALSE
This function returns TRUE for <phinterval> vectors and returns
FALSE otherwise.
is_phinterval(phinterval())
#> [1] TRUE
is_phinterval(interval())
#> [1] FALSE