Monotonicity describes the property that values along a line is ever
increasing or decreasing, i.e. f(x) > f(x + 1) || f(x) < f(x + 1). The weak
version allows equality as well, i.e. f(x) >= f(x + 1) || f(x) <= f(x + 1).
Usage
is_monotone(x, dim = "both")
is_weakly_monotone(x, dim = "x")
is_selfintersecting(x)
Arguments
- x
A polyclid_polyline vector
- dim
Either "x" or "y" to indicate in which dimension to test
monotonicity in
Value
A logical vector with the same length as x
Details
If a polyline is not at least weakly monotone in one dimension there is a
chance that it intersects with itself. This can be queried by
is_selfintersecting().
Examples
sine <- polyline(
seq(0, 2*pi, length.out = 20),
sin(seq(0, 2*pi, length.out = 20))
)
is_monotone(sine, "x")
#> [1] TRUE
is_monotone(sine, "y")
#> [1] FALSE
poly <- polyline(
c(0, 1, 1, 2),
c(0, 1, 2, 3)
)
is_monotone(sine, "x")
#> [1] TRUE
is_weakly_monotone(sine, "x")
#> [1] TRUE
