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visits member for 2 years, 9 months
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19h
revised Phase portrait on a cylinder
Transparency added
19h
revised Phase portrait on a cylinder
Transparency added
22h
comment Phase portrait on a cylinder
(+1) I think it looks better with the cylinder added, though...
22h
answered Phase portrait on a cylinder
1d
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.
1d
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.
1d
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.
1d
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]]]
1d
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.
1d
reviewed Close Problem with DSolve
1d
reviewed Close How do I extract the coordinates of a GeoGraphics polygon?
2d
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.
2d
comment Undertermined gauges
Nobody here will understand this question unless you post an example (what's "extract") and define your terminology. In Mathematica, this is what gauges are.
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.
Oct
26
comment Poets of the 19th century
@DumpsterDoofus I thought that was Mao Zedong...
Oct
25
comment Poets of the 19th century
Lenin was a poet??
Oct
25
comment Why is it so complicated to simplify a complex conjugate?
@BobHanlon is right. All the issues here are caused by some very basic misunderstandings about syntax. Assuming only affects commands that take the option Assumptions. Simplify is one of those, but it must be inside the Assumptions. The other code block contains logical statements which have no effect at all on the subsequent lines because they aren't put into the form of Assuming or $Assumptions. I think there must be a duplicate but can't find it right now.
Oct
25
comment Why is it so complicated to simplify a complex conjugate?
Related: Remove annoying Conjugate
Oct
24
reviewed Close Copy/Pasting code that contains double quotation marks leads to broken code