Skip to main content

button - Evaluation order control


This question is related to Evaluation order of Button's action


Concusion was, Button[]'s actions are evaluated in preemptive link so "the code that needs to be run for the new cells to be created and formatted needs to wait until the preemptive evaluation has finished". To deal with it we only have to add Method -> "Queued" for Button.


I've thougth that in case:


Button[ "X", x = 3; Pause @ 1; y = 4]
Dynamic @ x
Dynamic @ y

where cells for x and y are created before pushing Button I don't have to use Method -> "Queued". However it seems I have to because Pause is again evaluated at the first place.


This is not a big problem since I know how to deal with it but I like to know why something works not the way I thought it would.



There is something more: What if I'm working with customized button based on EventHandler, let's take basic case:


SetAttributes[ GButton, HoldRest]
GButton[ob_, proc_] := DynamicModule[{},
EventHandler[
Framed[ob, Alignment -> Center],
{"MouseDown" :> (proc)}, PassEventsUp -> False,
PassEventsDown -> False]];

This kind of button works as a standard Button but how can I add anything that works as Method -> "Queued" in Button? I need something opposite to PreemptProtect function.



Answer




Check what The Futz just said. However, you can go the ugly workaround way. Not recommended, since I don't think you have any guarantees that your code will be evaluated exactly once only when you click the button, but up to you.


Try this


Print@"I dare you to move the slider after pressing the button"; \
Slider[]
EventHandler[Framed["Benjamin Button"],
"MouseDown" :> (Pause[3];
Print@"If you couldn't, it was preemptive")]

and compare with this


Print@"I dare you to move the slider after pressing the button"; \

Slider[]
DynamicModule[{trigger = 0},
DynamicWrapper[
EventHandler[Framed["Benjamin Button"], "MouseDown" :> (++trigger)],
If[trigger =!= 0,
Refresh[Pause[3]; Print@"If you couldn't, it was preemptive",
None]], SynchronousUpdating -> False
]
]

Comments

Popular posts from this blog

plotting - Filling between two spheres in SphericalPlot3D

Manipulate[ SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, Mesh -> None, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], {n, 0, 1}] I cant' seem to be able to make a filling between two spheres. I've already tried the obvious Filling -> {1 -> {2}} but Mathematica doesn't seem to like that option. Is there any easy way around this or ... Answer There is no built-in filling in SphericalPlot3D . One option is to use ParametricPlot3D to draw the surfaces between the two shells: Manipulate[ Show[SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], ParametricPlot3D[{ r {Sin[t] Cos[1.5 Pi], Sin[t] Sin[1.5 Pi], Cos[t]}, r {Sin[t] Cos[0 Pi], Sin[t] Sin[0 Pi], Cos[t]}}, {r, 1, 2 - n}, {t, 0, Pi}, PlotStyle -> Yellow, Mesh -> {2, 15}]], {n, 0, 1}]

plotting - Plot 4D data with color as 4th dimension

I have a list of 4D data (x position, y position, amplitude, wavelength). I want to plot x, y, and amplitude on a 3D plot and have the color of the points correspond to the wavelength. I have seen many examples using functions to define color but my wavelength cannot be expressed by an analytic function. Is there a simple way to do this? Answer Here a another possible way to visualize 4D data: data = Flatten[Table[{x, y, x^2 + y^2, Sin[x - y]}, {x, -Pi, Pi,Pi/10}, {y,-Pi,Pi, Pi/10}], 1]; You can use the function Point along with VertexColors . Now the points are places using the first three elements and the color is determined by the fourth. In this case I used Hue, but you can use whatever you prefer. Graphics3D[ Point[data[[All, 1 ;; 3]], VertexColors -> Hue /@ data[[All, 4]]], Axes -> True, BoxRatios -> {1, 1, 1/GoldenRatio}]

plotting - Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1.