trigger at TDM/2 only

[cerr]

MRAB,

Thanks for the hint! Yep, that's much easier!

Thanks! :)
Ron

On Thursday, June 6, 2013 5:49:55 PM UTC-7, MRAB wrote:
> On 07/06/2013 01:03, cerr wrote:
> 
> > Hi,
> 
> >
> 
> > I have a process that I can trigger only at a certain time. Assume I have a TDM period of 10min, that means, I can only fire my trigger at the 5th minute of every 10min cycle i.e. at XX:05, XX:15, XX:25... For hat I came up with following algorithm which oly leaves the waiting while loop if minute % TDM/2 is 0 but not if minute % TDM is 0:
> 
> > 	min = datetime.datetime.now().timetuple().tm_hour*60 + datetime.datetime.now().timetuple().tm_min
> 
> > 	while not (min%tdm_timeslot != 0 ^ min%(int(tdm_timeslot/2)) != 0):
> 
> > 		time.sleep(10)
> 
> > 		logger.debug("WAIT "+str(datetime.datetime.now().timetuple().tm_hour*60 + datetime.datetime.now().timetuple().tm_min))
> 
> > 		logger.debug(str(min%(int(tdm_timeslot/2)))+" - "+str(min%tdm_timeslot))
> 
> > 		min = datetime.datetime.now().timetuple().tm_hour*60 + datetime.datetime.now().timetuple().tm_min
> 
> > 	logger.debug("RUN UPDATE CHECK...")
> 
> >
> 
> > But weird enough, the output I get is something like this:
> 
> > I would expect my while to exit the loop as soon as the minute turns 1435... why is it staying in? What am I doing wrong here?
> 
> >
> 
> > WAIT 1434
> 
> > 3 - 3
> 
> > WAIT 1434
> 
> > 4 - 4
> 
> > WAIT 1434
> 
> > 4 - 4
> 
> > WAIT 1434
> 
> > 4 - 4
> 
> > WAIT 1434
> 
> > 4 - 4
> 
> > WAIT 1434
> 
> > 4 - 4
> 
> > WAIT 1435
> 
> > 4 - 4
> 
> > WAIT 1435
> 
> > 0 - 5
> 
> > WAIT 1435
> 
> > 0 - 5
> 
> > WAIT 1435
> 
> > 0 - 5
> 
> > WAIT 1435
> 
> > 0 - 5
> 
> > WAIT 1435
> 
> > 0 - 5
> 
> > WAIT 1436
> 
> > 0 - 5
> 
> > RUN UPDATE CHECK...
> 
> >
> 
> Possibly it's due to operator precedence. The bitwise operators &, |
> 
> and ^ have a higher precedence than comparisons such as !=.
> 
> 
> 
> A better condition might be:
> 
> 
> 
>      min % tdm_timeslot != tdm_timeslot // 2
> 
> 
> 
> or, better yet, work out how long before the next trigger time and then
> 
> sleep until then.