# User Portlet

Neil Singer
Discussions
Gianluca, This works: ParametricPlot3D[{x, y, x}, Element[{x, y}, Disk[]], RegionFunction -> Function[{x, y, z}, x^2 + y^2 Function[{x, y, z}, Element[{x, y}, Disk[]]]] but you should report that the element syntax no longer...
Daniel, Sorry I missed your request. > I want to know why you use Im[(x + y*I)^2 + 1] + 8)/16 to scale the value to [0,1]? why not use Im[(x + y*I)^2 + 1] /8 directly? The Hue function ranges from 0 to 1 but your data ranges from -8 to 8 so...
Jules, Your errors mostly have to do with a blank item in the option list (you have two commas in a row). Additionally, unless you specify that the options of Button are also options of fn1, it will not work. This works: ops =...
... and in certain cases you will need to specify a region...
While Michael's post is still a bit faster by avoiding the If[], this addition to the Compiled version makes it parallel and almost the same speed as Michael's clever post which avoids the If[] (I forgot to try the parallelization last night which...
Sergei, Every time I’ve seen discrepancies like this it usually stems from a definition or branch cut in a function (probably related to the issue Gianluca pointed out). You have surpassed my knowledge of mathematics on this one! I would ask...
In fact, you can simplify it further by doing this: Block[{x, y}, TextCell[ Column[{ToString[x''[t]/Sqrt[x + y] == 5 y , TraditionalForm] (*I want x to always be a symbol*)}, Spacings -> 0.5] , "Text",...
Shruti, You need to do this: Plot[(x[n, t] /. s /. n -> 20) , {t, 0, 10}, PlotRange -> All] You want to plot x[n,t] using the solution, s: x[n,t] /. s s has a substitution rule for x and q in the form of an interpolation...
Art, It appears to be related to the DAE and its index reduction. I would contact tech support to see why this doesn't work. I even tried to force a[t] to take on discrete values of -1,1 and it failed: DiscreteVariables -> {a \[Element]...
Your fitting function is a horrible fit to your data. You must have something wrong. To visualize this do the following: Manipulate[ Show[ListLinePlot[data1, PlotStyle -> Orange], Plot[2*Sqrt[diffusion]*x*(1/L)*(Pi^(-0.5) +...