How to write a function to generate a sequence of points in R? -


this pdf dealing with: 

fx = 0.3 if (0<=x<1) 0.1 if (1<=x<2) 0.25 if (2<=x<3) 0.15 if (3<=x<4) 0.2 if (4<=x<5) 0 otherwise

i have write function gen_xy generate sequence of points (x, y) uniformly distributed in (0, 5) x (0, 0.5) until 1 lies in region under curve of y = fx(x).

this code far:

fx <- function(x) c(0, 0.3,0.1,0.25,0.15,0.20, 0) [findinterval(x, c(-inf, 0:5,  inf))]  x <- runif(n,0,5) fx <- stepfun(x = 0:5, y = c(0,0.3,0.1,0.25,0.15,0.20,0)) plot(fx, ylim = c(0,0.5),xlim = c(0,5), main = 'f(x)')

now attempt @ writing code function: 

gen_xy <- function() {     done=0     while(done==0) {         x=runif(1,0,5)          y=runif(1,0,0.5)          print(c("x,y",c(x,y)))          if(y < fx(x)) {              done=1          }     }     xy=c(x,y)     xy }

but think part if(y < fx) wrong?

i need generate sample of 1000 points , plot them check if appropriate sample under curve of y=fx. how go writing such code?

your gen_xy() function understand want ... generates sequence of points, until 1 lies under line ... , breaks out of loop. tried , generated couple of points ... ... add them plot if ad points(x,y,col="red") or loop.

to genrate 1000 points like:

     x=runif(1000,0,5)      y=runif(1000,0,0.5)

this can put on plot points(x,y)

but not sure mean appropriate sample. ??

you can compare generated points against curve again:

     y < fx(x)

and subset them doing x[y < fx(x)] , y[y < fx(x)].


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