Handling interrupts in long-running R functions

bretschr · 2021-09-15T07:05:46Z

Dear Ivan Krylov, Re: > On 10 Sep 2021, at 16:43, Ivan Krylov wrote: > > Hello everyone, > > I'm writing an R function that may be running for "long" periods of > time (think tens of minutes), and I would like to be able to tell it: > "please stop what you're doing and return the not-yet converged results > as they are for inspection". > > The behaviour I'm striving for is > > 1) User presses interrupt > 2) Function handles the interrupt and returns as if the co

bretschr

Wed, Sep 15, 2021 12:05 AM

Dear Ivan Krylov,


Re:

Just a crazy idea: the sound input of a Mac/PC might serve as an interrupt.
Record a short bit and assess the amplitude: moderate = signal, loud = break.
See my source code below. This works on my MacBook Air with Mojave.
When I snap my fingers, the amplitude is moderate (3 through 10), when tapping 
or scratching the microphone, amplitude is over 20.

Hoping this might help,
With best regards,


Franklin
------


R source code:


#  sound as interrupt.R
#  with package audio
#  15-09-2021
#  ====================
#  NB First switch audio input to the wanted device
#     (microphone, sound input or 3rd party device)
#  flick your fingers = signal (m about 3 through 10)
#  tap the microphone -> stop  (m > 20)
library(audio)
samp.rate = 44100
rectime = 1  #  second
nsamples = samp.rate * rectime
repeat {
	sample <- record(2*nsamples, rate=44100, channels=2)
	wait(sample) # wait for the recording to finish
	sound <- sample$data # get the result
	m = max(sound)
	print(m)
	if (m > 0.5) alarm()  #  or the desired routine
	if (m > 20) {save.wave(sound, "sound from audio input.wav"); break}   # stop program
	}
#  end




Franklin Bretschneider
Dept of Biology
Utrecht University
f.bretschneider at uu.nl

Handling interrupts in long-running R functions

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