Re: Re: Re: How to find which variable caused

*To*: mathgroup at smc.vnet.net*Subject*: [mg103913] Re: [mg103879] Re: [mg103821] Re: How to find which variable caused*From*: DrMajorBob <btreat1 at austin.rr.com>*Date*: Mon, 12 Oct 2009 06:37:52 -0400 (EDT)*References*: <200910101109.HAA12701@smc.vnet.net>*Reply-to*: drmajorbob at yahoo.com

Why does that Row display as a column? (Even when I stretch the window over two monitors.) Replacing Row with Column gives the same result, except that there's a lot of excess space in the Text box... even when I specify 0 as the 3rd argument, as in Manipulate[ Column[{Dynamic[ Refresh[xFlag = True; yFlag = False; "", TrackedSymbols -> {x}]], Dynamic[Refresh[xFlag = False; yFlag = True; "", TrackedSymbols -> {y}]], Dynamic[Text[ StringJoin["you moved the ", Which[xFlag, "x", yFlag, "y"], " slider"]]]}, Left, 0], {x, 0, 1}, {y, 0, 1}, {{xFlag, False}, ControlType -> None}, {{yFlag, False}, ControlType -> None}] Why is that? Bobby On Sat, 10 Oct 2009 06:09:45 -0500, John Fultz <jfultz at wolfram.com> wrote: > This is a very simple version of what you asked for that doesn't solve > some of > the fundamental problems you'll probably come across, but it shows you > the > techniques to solving them. Principally... > > * Contain all evaluation inside of scoped Dynamics to prevent the entire > Manipulate from refreshing. > * Add flag variables (and perhaps you'll want other variables, too) as > control > variables, but with ControlType->None so they don't appear. > * Use separate Dynamics, which display inside a Row[] as empty strings > (this is > important...remember that if a Dynamic doesn't display onscreen, then > there's > nothing available to update...see my previous posts on Dynamic if you're > at all > confused about this), to track the individual variables. > + These separate Dynamics each scope a single variable only. > + The scoped variable is determined by using Refresh with > TrackedSymbols > > One of the problems my version doesn't solve is sensibly setting a start > condition, so the evaluation assumes that the initial state has changed > the y > parameter (as a result of the initial creation of the flag-tracking > dynamics). > That's a problem I'll let you figure out. > > > Manipulate[Row[{ > Dynamic[ > Refresh[xFlag = True; yFlag = False; "", TrackedSymbols -> {x}]], > Dynamic[ > Refresh[xFlag = False; yFlag = True; "", TrackedSymbols -> {y}]], > Dynamic[ > Text[StringJoin["you moved the ", Which[xFlag, "x", yFlag, "y"], > " slider"]]] > }], > {x, 0, 1}, {y, 0, 1}, > {{xFlag, False}, ControlType -> None}, > {{yFlag, False}, ControlType -> None}] > > > Sincerely, > John Fultz > jfultz at wolfram.com > User Interface Group > Wolfram Research, Inc. > > > On Thu, 8 Oct 2009 07:49:43 -0400 (EDT), Nasser Abbasi wrote: >> >> >> "Nasser Abbasi" <nma at 12000.org> wrote in message >> news:hafbgr$j4r$1 at smc.vnet.net... >> >>>> Again, I want something like this >>>> >>>> Manipulate[ >>>> process[( pickTheCorrectControlVariableWhichChanged ], >>>> {a, 0, 1}, {b, 0, 1}, Initialization :> >>>> >>>> (process[arg_] := Module[{}, Plot[Sin[arg*x], {x, -Pi, Pi}]]) >>>> ] >>>> >> >>> I made some progress and I think I have a solution. >>> >>> I save the old value of each control variable in a global variable, >>> then >>> in >>> the Manipulate expression, I check, using an If statement which current >>> value of the control variable is different from the old value. I got it >>> to >>> work ok finally. >>> >>> Here is an example: >>> >>> olda = 999; >>> oldb = 999; >>> >>> Manipulate[ >>> If[olda != a, {olda = a; Style[StringJoin["a=", ToString[a]]]}, >>> >>> If[oldb != b, {oldb = b; Style[StringJoin["b=", ToString[b]]]}, >>> >>> Text["this message should NOT show up!"]]], {a, 0, 1}, {b, 0, 1}, >>> >>> LocalizeVariables -> True, TrackedSymbols -> {a, b}] >>> >>> >> It is me again, with the same problem. >> >> I found out that I can NOT use global variables in a demo, and I also >> can't >> wrap the whole Manipulate inside a module. Any one of the above method >> will >> have solved this problem, but rules are rules, so now I have to find >> another >> solution. So I am stuck again. >> >> Before I recode everything again, which I would hate to do, I thought= > I'll >> ask one more time, may be some expert can have a solution. But this one= > is >> really hard. >> >> I'll explain again the problem to make sure we are all clear on it. >> >> I need to write a Manipulate where inside the Manipulate I need to >> detect >> which slider or in other words, which control variable was changed. i.e. >> which slider the user just changed to cause the Manipulate expression to >> be >> generated. (I need to do this so I can do different processing based on >> the >> slider that was selected) >> >> We all know that Manipulate generates a new version of its expression= > when >> one of the control variables changes value. I need to know which >> control >> variable changed. >> >> There is the general layout >> >> Manipulate[ >> >> (* expression that uses control variables *) >> >> , >> >> (* controls here which update the control variables values *) >> ] >> >> But there are restriction on the solution, since this will be for a >> demo. >> Again, there can NOT be global variables used, (i.e. no variables in the >> Manipulate initialization section, since these are global), and there >> can >> NOT be a module around Manipulate[], i.e. no Module[{...}, >> Manipulate[...]] >> allowed. >> >> Here is a small code to show the problem >> >> Manipulate[ >> Text[StringJoin["you moved the ", "x or y", " slider"]], >> {x, 0, 1}, >> {y, 0, 1} >> ] >> >> Could someone modify the above, so that the code above will tell which >> slider the user _just_ moved? >> >> It seems like an impossible problem for me to solve without the use of >> global variables or a module around Manipulate. >> >> Here is what I tried so far, and this fail: >> >> Manipulate[ >> Which[ >> >> x != oldx, >> {oldx = x; Text[StringJoin["you moved the ", "x ", " slider"]]}, >> >> y != oldy, >> {oldy = y; Text[StringJoin["you moved the ", "y ", " slider"]]}, >> >> True, Text["why Ami here??"] >> ], >> >> {x, 0, 1}, >> {y, 0, 1}, >> {oldx, -999, ControlType -> None}, >> {oldy, -999, ControlType -> None} >> ] >> >> The reason it fail is because oldx and oldy are updated to the same >> value >> of >> x and y whenever x or y changes before I get the chance to do the >> comparison. I.e. when the new version of the expression is generated, >> oldx=x >> and oldy=y each time. This seems to consequences of Manipulate= > generating >> DynamicModule[] for the whole thing. You can see this by using the >> SnapShot >> option on the Manipulate output. This will generate the whole expression >> form. (Nice tool). >> >> If someone can make it so that the above will display the correct >> message >> each time, then I would declare that person to be the Mathematica Guru >> of >> the year. >> >> I think I have reached the limit of my current Mathematica understanding >> when it comes to internals of Manipulate and Dynamics to be to solve >> this >> one. But I'll keep on looking. >> >> Thank you, >> --Nasser > > > -- DrMajorBob at yahoo.com

**References**:**Re: Re: How to find which variable caused the trigger in Manipulate[]***From:*John Fultz <jfultz@wolfram.com>

**Re: Re: Re: undocumented feature: TableView**

**Re: Re: Re: How to find which variable caused the trigger in Manipulate[]**

**Re: Re: How to find which variable caused the trigger in Manipulate[]**

**Re: Re: How to find which variable caused the trigger in Manipulate[]**