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Nov
13
awarded  Enlightened
Nov
13
awarded  Nice Answer
Nov
8
comment What are the Mathematica functions to plot in a 3D version of elliptical coordiante system?
A Mathematica answer can not be given until the mathematical purpose of the question is clarified. It seems to be mainly a mathematics issue to which the answer would be quite broad. Is it supposed to be an orthogonal coordinate system? What, if any, symmetries is it supposed to have?
Nov
8
comment Plotting in Elliptical coordinate system
The meaning of the term "elliptical coordinate system" is that it provides a parametrization of points in a Cartesian frame, where every point is the intersection of an ellipse and a hyperbola. So to plot in this coordinate system is synonymous to forming Cartesian plot in the end, and therefore it is not clear at all what you mean by not having elliptical coordinates linked to the Cartesian ones. The name "elliptical coordinates" itself comes from the elliptical shape of the coordinate lines when drawn in Cartesian coordinates!
Nov
4
reviewed Close How can i construct a 3D surface pass through a curve defined by formula and some other controllable points?
Oct
30
revised How do I display the parameter value in animate, similar to how it's done in manipulate?
Formatting, missing var.
Oct
30
comment How do I display the parameter value in animate, similar to how it's done in manipulate?
@Joe I'm guessing you're using Mathematica version 8, or at least not the newest version. In version 8, I can confirm that Appearance -> "Labeled" doesn't work. Since you accepted the solution, does that mean you're not looking for a workaround anymore?
Oct
29
revised Phase portrait on a cylinder
Transparency added
Oct
29
revised Phase portrait on a cylinder
Transparency added
Oct
29
comment Phase portrait on a cylinder
(+1) I think it looks better with the cylinder added, though...
Oct
29
answered Phase portrait on a cylinder
Oct
28
comment Oval or Bunimovich stadium
Yes, using a case distinction. But as I said initially, you have to make your question more specific so that anyone who answers won't get dragged into an extended discussion trying to hit a moving target because the goal is initially set too broadly. E.g., is speed a main concern, or code readability, or user-friendliness, or extensibility to non-convex shapes, etc. Seems to me like a tutorial would be needed, too.
Oct
28
comment Oval or Bunimovich stadium
Closely related: Poincaré map for dynamic billiard. Both are essentially requests for code, building on a copy of the same demonstration authored by Dan Reznik.
Oct
28
comment Oval or Bunimovich stadium
Of course I know how to do all this because I've worked on it extensively, but I don't think an answer is within the scope of this Q&A format. You would have to narrow down your question to a specific Mathematica issue. I would prefer to post my own code instead of trying to modify the code you posted without any comments.
Oct
28
comment How to redefine the type of multiplication in Det
The Block approach doesn't work for numerical matrices, e.g., Block[{Times = f}, Det[PauliMatrix[2]]]
Oct
28
comment How to redefine the type of multiplication in Det
Probably it would be good to explain what your ultimate goal is, and what the specific properties of the function Fun are. Without that information, there is a good chance that any effort to answer this could be misdirected.
Oct
28
reviewed Close Problem with DSolve
Oct
28
comment Derivatives of functions with arbitrary number of variables?
@rhermans Can you explain what you think the OP means? I do not understand it. This may be because the question is too broad and "formalism" is not defined.
Oct
27
comment A Product function for matrix products
Sometimes defining a new function for a simple task can make the code less readable. In this instance, I think that is the case because the syntax as shown by @DanielLichtblau is concise and sufficiently expressive to be self-explanatory.
Oct
26
comment Derivatives of functions with arbitrary number of variables?
When you try D[f[x1, x2, xn], x2] you do get an unambiguous result, right? So I think you have to state the problem more clearly with an example.