LPS: Loops Per Second

Rate-controlled loop execution.

Installation

Add this line to your application's Gemfile:

gem 'lps'

And then execute:

$ bundle

Or install it yourself as:

$ gem install lps

Usage

# - Loops 10 times per second
# - Loops for 10 seconds
now = Time.now
LPS.freq(10).while { Time.now - now < 10 }.loop do
  # do something
end


# - Loops 10 times per second
# - Loops indefinitely
LPS.freq(10).loop do
  # do something
end


# Every 0.1 second
LPS.interval(0.1).loop do
  # do something
end

Breaking out of the loop

LPS.freq(10).loop { break if rand(10) == 0 }

Changing loop frequency

i = 0
LPS.while { i < 100 }.loop do |lps|
  print '.'
  lps.freq = i += 1
end

Falling behind

With LPS, the given loop block is run synchronously, which means that if the block execution takes longer than the interval for the given frequency, (e.g. 0.01 second for 100) it may not be possible to achieve the desired frequency.

12.times.map { |i| 1 << i }.each do |ps|
  cnt = 0
  now = Time.now
  LPS.freq(ps).while { Time.now - now <= 1 }.loop do
    cnt += 1
    sleep 0.01
  end

  puts [ps, cnt].join ' => '
end

1 => 1
2 => 2
4 => 4
8 => 8
16 => 16
32 => 32
64 => 64
128 => 98
256 => 98
512 => 99
1024 => 97
2048 => 98