| Type: | Package |
| Title: | Speed Limiter to Control Rate of Execution of Loops |
| Version: | 0.1.3 |
| Maintainer: | Mike Cheng <mikefc@coolbutuseless.com> |
| Description: | It can be necessary to limit the rate of execution of a loop or repeated function call e.g. to show or gather data only at particular intervals. This package includes two methods for limiting this execution rate; speed governors and timers. A speed governor will insert pauses during execution to meet a user-specified loop time. Timers are alarm clocks which will indicate whether a certain time has passed. These mechanisms are implemented in 'C' to minimize processing overhead. |
| License: | MIT + file LICENSE |
| Encoding: | UTF-8 |
| URL: | https://github.com/coolbutuseless/governor |
| BugReports: | https://github.com/coolbutuseless/governor/issues |
| RoxygenNote: | 7.3.2 |
| Suggests: | knitr, rmarkdown |
| VignetteBuilder: | knitr |
| NeedsCompilation: | yes |
| Packaged: | 2024-08-25 05:31:21 UTC; mike |
| Author: | Mike Cheng [aut, cre, cph] |
| Repository: | CRAN |
| Date/Publication: | 2024-08-25 07:50:02 UTC |
Disable/enable a governor
Description
When disabled a governor always returns immediately without any waiting
Usage
gov_enable(gov)
gov_disable(gov)
Arguments
gov |
object created by |
Value
None.
Examples
gov <- gov_init(1/30)
gov_disable(gov)
gov_enable(gov)
Initialize a governor to control the speed of a loop
Description
Initialize a governor to control the speed of a loop
Usage
gov_init(interval, alpha = 0.4, alpha_decay = 0.95, alpha_target = 0.05)
Arguments
interval |
desired interval in seconds E.g. |
alpha |
initial learning rate used to adjust wait time. Default: 0.4 |
alpha_decay |
rate at which alpha decays. Default: 0.95 i.e. 5 each iteration |
alpha_target |
the baseline alpha to reach when running long term. default: 0.05 |
Value
gov object to be used with gov_wait()
Examples
# This loop should take approx 1 second as the governor will limit
# the loop to run every thirtieth of a second.
gov <- gov_init(1/30)
system.time({
for (i in 1:30) {
gov_wait(gov)
}
})
Wait an appropriate amount of time within a for-loop to match the desired
interval set in gov
Description
Wait an appropriate amount of time within a for-loop to match the desired
interval set in gov
Usage
gov_wait(gov)
Arguments
gov |
object created by |
Value
Logical value. If TRUE then the governor is suggesting that
the work for next loop be skipped if the loop interval is to
be maintained in the long term.
Examples
# This loop should take approx 1 second
gov <- gov_init(1/30) # interval = 0.0333 seconds
system.time({
for (i in 1:30) {
Sys.sleep(0.01) # Work done in loop
gov_wait(gov) # Compensate to keep interval loop time
}
})
Check the status of a timer
Description
Check the status of a timer
Usage
timer_check(timer)
Arguments
timer |
timer object returned by |
Value
logical indicating if timer was triggered. If TRUE, then
the internal state of the timer will be reset (so that it will
trigger again after another duraction has elapsed)
Examples
# Run two timers in a tight while loop
# The short timer should trigger every 0.1 seconds
# The long timer will trigger after 1 second
# Note that the timers will reset every time they trigger (after returning TRUE)
long_timer <- timer_init(1)
short_timer <- timer_init(0.1)
counter <- 0L
while(TRUE) {
if (timer_check(long_timer)) {
cat("\nLong timer fired at count: ", counter, "\n")
break;
}
if (timer_check(short_timer)) {
cat("Short timer fired at count: ", counter, "\n")
}
counter <- counter + 1L
}
Disable/enable a timer
Description
When disabled a timer always immediately returns FALSE
Usage
timer_enable(timer)
timer_disable(timer)
Arguments
timer |
timer object returned by |
Value
None.
Examples
timer <- timer_init(1)
timer_disable(timer)
timer_enable(timer)
Create a timer object which will return TRUE when checked and the
given duration has elapsed.
Description
The timer will automatically reset any time it is checked (via check_timer())
and it returns TRUE.
Usage
timer_init(duration, reset_mode = "checked")
Arguments
duration |
timer duration in seconds |
reset_mode |
one of 'checked' (default) or 'created' . If 'checked', then
when the timer is reset the next alarm will be set to |
Value
a timer object to used with timer_check()
Examples
# Run two timers in a tight 'while' loop
# The short timer should trigger every 0.1 seconds
# The long timer will trigger after 1 second
# Note that the timers will reset every time they trigger (after returning TRUE)
long_timer <- timer_init(1)
short_timer <- timer_init(0.1)
counter <- 0L
while(TRUE) {
if (timer_check(long_timer)) {
cat("\nLong timer fired at count: ", counter, "\n")
break;
}
if (timer_check(short_timer)) {
cat("Short timer fired at count: ", counter, "\n")
}
counter <- counter + 1L
}