mirai (Race)

Accepts a list of 'mirai' objects, such as those returned by mirai_map(). Returns the index of the first resolved 'mirai'. If any mirai is already resolved, returns immediately. Otherwise waits for at least one to resolve, blocking but user-interruptible.

Usage

race_mirai(x, .compute = NULL)

Arguments

x

(list) of 'mirai' objects.

.compute

(character) name of the compute profile. Each profile has its own independent set of daemons. NULL (default) uses the 'default' profile.

Value

Integer index of the first resolved 'mirai' (invisibly), or 0L if the list is empty.

Details

All of the 'mirai' objects supplied must belong to the same compute profile.

When called on a list where some mirais are already resolved, returns the index of the first resolved mirai immediately without waiting. When all mirais are unresolved, blocks until at least one resolves. If multiple mirais resolve during the same wait iteration, returns the index of the first resolved in list order.

This enables an efficient "process as completed" pattern:

  remaining <- list(m1, m2, m3)
  while (length(remaining) > 0) {
    idx <- race_mirai(remaining)
    process(remaining[[idx]]$data)
    remaining <- remaining[-idx]
  }
  

See also

call_mirai()

Examples

if (FALSE) { # interactive()
daemons(2)
m1 <- mirai({ Sys.sleep(0.2); "one" })
m2 <- mirai({ Sys.sleep(0.1); "two" })
m3 <- mirai({ Sys.sleep(0.3); "three" })
remaining <- list(m1, m2, m3)
while (length(remaining) > 0) {
  idx <- race_mirai(remaining)
  print(remaining[[idx]]$data)
  remaining <- remaining[-idx]
}
daemons(0)
}