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How to use custom Dynamic inside Manipulate


I was wondering if it is possible to use a custom Dynamic[var, function] inside a Manipulate. The reason for the need is this:


Suppose you have a time consuming computation like


timeConsuming[x_] := (Pause[1]; x)

and you want to use it in a Manipulate. Writing


DynamicModule[{y},
 Manipulate[

  y = timeConsuming[x]; {x, y, other},
  {x, 0, 1},
  {other, 0, 1}]
 ]

entails the following issue: you have to wait for timeConsuming to be computed even when you change other and leave x unmodified. A (simple) solution is to code the dynamic by hand:


DynamicModule[{x = 0, y = timeConsuming[0], other = 0},
 Panel@Column[{
    Grid[{
      {"x", Slider[Dynamic[x, (x = #; y = timeConsuming[x]) &], {0, 1}]},

      {"other", Slider[Dynamic[other], {0, 1}]}
      }],
    Dynamic@{x, y, other}
    }]
 ]

This is feasible, but as a drawback makes you renounce all other Module's conveniences.


I tried coding something like


Module[(* result *), {x, 0, 1, some-suitable-function}]


but had no success in the attempt. A (clean) use of Manipulate would be much appreciated.


Just to summarize, the question is: How can I make some statements be executed only when some specified controls are touched?



Answer



Is this what you're after?


timeConsuming[x_] := (Pause[1]; x);
DynamicModule[{y},
 Manipulate[y = timeConsuming[x]; {Dynamic@x, y, Dynamic@other},
  {x, 0, 1}, {other, 0, 1},
  SynchronousUpdating -> False]
 ]


SynchronousUpdating -> False keeps the front end from being blocked while timeConsuming is computing, and Dynamic lets different segments be updated. So x and other both update when the sliders are moved, and y is updated one second after x is.


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