I am trying to write a function that generates random paths for a Travelling Salesman Problem.

Here is the data:

```
final_data = data.frame(Longitude = rnorm(19, 40,1), Lattitude = rnorm(19, -65,1))
final_data$id = 1:19
N <- nrow(final_data)
dists <- outer(seq_len(N), seq_len(N), function(a,b) {
geosphere::distHaversine(final_data[a,1:2], final_data[b,1:2]) })
D <- as.matrix(dists)
####
d = 19
fix_num <- 1
```

Here is the function for 100 random paths:

```
results <- list()
resultss <- list()
for (i in 1:100)
{
start.time <- Sys.time()
iteration = i
relations_i = tibble(
from = c(fix_num, sample(setdiff(1:d, fix_num))),
to = lead(from, default=from[1]),
)
relations_i = data.frame(relations_i)
relations_i$iteration = i
m<-dists
my_sums_i = function(relations_i, m) {
r = as.matrix(relations_i)
if(mode(r) != "numeric") mode(r) = "numeric"
sum(m[r])}
m_i = my_sums_i(relations_i, m)
end.time <- Sys.time()
time.taken_i <- end.time - start.time
m_i$time = time.taken_i
results[[i]] <- m_i
resultss[[i]] <- relations_i
}
results_1 <- data.frame(do.call(rbind.data.frame, results))
results_2 <- data.frame(do.call(rbind.data.frame, resultss))
####
```

This seems to work fine - the problem happens when I Increase the number of paths (e.g. i =100 vs. i = 1000):

```
results <- list()
resultss <- list()
for (i in 1:1000)
{
start.time <- Sys.time()
iteration = i
relations_i = tibble(
from = c(fix_num, sample(setdiff(1:d, fix_num))),
to = lead(from, default=from[1]),
)
relations_i = data.frame(relations_i)
relations_i$iteration = i
m<-dists
my_sums_i = function(relations_i, m) {
r = as.matrix(relations_i)
if(mode(r) != "numeric") mode(r) = "numeric"
sum(m[r])}
m_i = my_sums_i(relations_i, m)
end.time <- Sys.time()
time.taken_i <- end.time - start.time
m_i$time = time.taken_i
results[[i]] <- m_i
resultss[[i]] <- relations_i
}
results_1 <- data.frame(do.call(rbind.data.frame, results))
results_2 <- data.frame(do.call(rbind.data.frame, resultss))
```

- For some reason, when there are more paths, NA's are produced in the results.
- Is there a way to fix this?

Thank you!