[R] Skip jumps in curve

[Duncan Murdoch]

On 13/02/2024 10:29 a.m., Leo Mada via R-help wrote:
> Dear R-Users,
> 
> Is there a way to skip over without plotting the jumps/discontinuities in curve()?
> 
> I have not seen such an option, but maybe I am missing something.
> 
> plot.gamma = function(xlim = c(-6, -1), ylim = c(-1,3), hline = NULL, n = 1000) {
>     curve(gamma(x), from = xlim[1], to = xlim[2], ylim=ylim, n=n);
>     if( ! is.null(hline)) abline(h = hline, col = "green");
> }
> 
> Euler = 0.57721566490153286060651209008240243079;
> plot.gamma(hline = Euler)
> 
> Adding an option to the function curve may be useful:
> options = c("warn", "silent", "unconnected")
> 
> This is part of some experiments in math; but that's another topic. For latest version:
> https://github.com/discoleo/R/blob/master/Math/Integrals.Gamma.Inv.R

If you know where the discontinuities are, plot multiple times with the 
discontinuities as endpoints:

plot.gamma = function(xlim = c(-6, -1), ylim = c(-1,3), hline = NULL, n 
= 1000) {
   start <- floor(xlim[1]):floor(xlim[2])
   end <- start + 1

   start[1] <- xlim[1]
   end[length(end)] <- xlim[2]

   n <- round(n/length(start))

   curve(gamma(x), from = start[1], to = end[1], ylim=ylim, n=n, xlim = 
xlim)
   for (i in seq_along(start)[-1])
     curve(gamma(x), from = start[i], to = end[i], add = TRUE, n)
   if( ! is.null(hline)) abline(h = hline, col = "green");
}

Euler = 0.57721566490153286060651209008240243079;
plot.gamma(hline = Euler)

If you don't know where the discontinuities are, it would be much 
harder, because discontinuities can be hard to detect unless the jumps 
are really big.

Duncan Murdoch