As shown in the following example, ControlActive does not seem to respond to controls such as SetterBar. Moving the slider resets the value of k, but changing the value of x via SetterBar does not.

Is there some other way to trigger an expensive calculation inside of a Manipulate when some discrete control variable is changed?

 Row[{x, Spacer[10], y, Spacer[10], ControlActive[k = 0, k++]}]
 , {x, {5, 6, 7, 8}, ControlType -> SetterBar}
 , {y, 0, 1}
 , Initialization :> (k = 0)
  • $\begingroup$ I would consider ControlActive a switch and not a trigger. Therefore your question asks two different things, that aren't necessarily related. $\endgroup$ – Karsten 7. Aug 7 '15 at 9:41

ControlActive doesn't respond to SetterBar, as changing a value using SetterBar doesn't make $ControlActiveSetting being True.

Here is one way to make using the SetterBar reset k:

 Row[{x, Spacer[10], y, Spacer[10], ControlActive[k = 0, k++], Spacer[10], 
 {x, {5, 6, 7, 8}, ControlType -> SetterBar, TrackingFunction -> (x = #; k = 0; &)}, 
 {y, 0, 1}, Initialization :> (k = 0)]
  • $\begingroup$ Great! Am I correct that this can be used generally to trigger an expensive calculation, only when the value of the SetterBar is changed? That would be very useful. $\endgroup$ – abwatson Aug 6 '15 at 22:19
  • $\begingroup$ @abwatson Yes, it should be. $\endgroup$ – Karsten 7. Aug 7 '15 at 9:04
  • $\begingroup$ @abwatson However, there are more ways to manage the evaluations inside a Manipulate. Some of them not suitable for your specific example, where k=0 seems to represents the expansive calculation and k++ the inexpensive one. The example in your question is more about how to set k=0 after clicking on the SetterBar. Your ControlActive just keeps k=0 as long as the Manipulator is used. $\endgroup$ – Karsten 7. Aug 7 '15 at 9:48
  • $\begingroup$ What are the other "ways to manage the evaluations inside a Manipulate?" I often have a need to perform an expensive calculation only when one of the control variables is changed. $\endgroup$ – abwatson Aug 7 '15 at 20:45
  • $\begingroup$ @abwatson For example using Refresh or Dynamic with TrackedSymbols as a second argument. You can find many examples on this site and in the tutorials (e.g. Advanced Manipulate Functionality). $\endgroup$ – Karsten 7. Aug 7 '15 at 21:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.