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I am wanting to make a function that times how long an evaluation takes to run dynamically, with the effect similar to if I were to use an online stopwatch and started it when I hit run. If the evaluation took 10 s i could watch the timer count up to that time. Any help? Ive tried to make my own already with various combinations of dynamic and timing, but have been unsuccessful.

Brandon Myers
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  • Absolute Timing captures the stopwatch-like time effect, but you will probably need to parallelize in order to visually see the timer. Otherwise the kernel finishes the entire evaluation before updating the dynamic content. – Bill Molchan Dec 09 '16 at 21:02

2 Answers2

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I would use Clock with PrintTemporary to run a timer and AbsoluteTiming to report the computation time. The following is quite easy to code on the fly when needed:

PrintTemporary@ Dynamic@ Clock[Infinity];
Sum[Pause[1]; i, {i, 3}] // AbsoluteTiming

Used this way, the clock runs completely in the Front End and shouldn't slow down the kernel at all in a multi-core, multi-threaded environment. The timer is visible until the evaluation is completed, at which point it is replaced by the results of AbsoluteTiming and the computation.

Michael E2
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  • I don't know why it needs to it calls the Kernel to get that value. – Kuba May 09 '17 at 15:39
  • @Kuba What value? I think Clock[] runs completely in the FE. t = Clock[..] would call the Kernel to store t (unless t was a DynamicModule variable). Is that what you're talking about? – Michael E2 May 09 '17 at 16:38
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    I mean that with LinkSnooper one can see that it is calling the Kernel. – Kuba May 09 '17 at 16:40
  • @Kuba Darn. I thought it didn't. I think my LinkSnooper is broken. It seems to break whenever I upgrade and I forget what I had to do to get it to work. Oh well, maybe I'll try to fix it. Thanks. – Michael E2 May 09 '17 at 16:43
  • @Kuba Maybe it's calling the kernel b/c of Infinity. – Michael E2 Mar 27 '18 at 21:25
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A very simple prototype:

Clear[stop, stopwatch];
stopwatch[b_] := If[b == 1, startTime = Now; stop = 0;
                    Dynamic[tracker = If[stop != 1, Clock[]]; 
                            Now - startTime,TrackedSymbols :> {tracker}], stop = 1;]

Testing:

stopwatch[1]
Integrate[Product[Sin[x/(2 k + 1)], {k, 0, 8}]/x^9, {x, 0, Infinity}] // AbsoluteTiming // First 
stopwatch[0]

(* Dynamic object, stops at 10.908s 
   10.8757  *)

So, there is a little bit of overhead associated with function call, but roughly you get the timing right.

Stitch
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