================================== Top new questions this week: ==================================
[Spacing out random walks so they don’t overlap] (http://mathematica.stackexchange.com/questions/94363/spacing-out-random-walks-so-they-dont-overlap)
From an external simulation program, I have lots of particle tracks which follow random walks, all of which start at or near the origin \((0,0)\). This means that when I plot the walks in Mathematica, ...
- asked by blochwave (20 votes), answered by kirma (8 votes)
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[How to avoid the wiggly text on Ticks and Labels when rotating 3D objects] (http://mathematica.stackexchange.com/questions/94470/how-to-avoid-the-wiggly-text-on-ticks-and-labels-when-rotating-3d-objects)
Motivation
I’m trying to do a nice animation of the rotation of a ParametricPlot3D . My problem is that the Ticks numbers and AxesLabel text wiggle with an undesirable noisy component as the ...
- asked by rhermans (16 votes), answered by P. Fonseca (8 votes)
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[Efficiently generating 2-D Gaussian random fields on the sphere] (http://mathematica.stackexchange.com/questions/94390/efficiently-generating-2-d-gaussian-random-fields-on-the-sphere)
Context
A couple of years ago I posted this question for an efficient code to generate an n-D Gaussian random field (sometimes called processes in other fields of research), which has applications in ...
- asked by chris (15 votes)
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[Pattern does not match with Orderless head] (http://mathematica.stackexchange.com/questions/94432/pattern-does-not-match-with-orderless-head)
Why does the following pattern matching not succeed?
ClearAll[f]; SetAttributes[f,Orderless]; HoldForm[f[a,d[],b,c]]/.HoldPattern[f[a,d[],b,z_]]:>{z} (* f[a,d[],b,c] *)
I expected that because f ...
- asked by bdforbes (14 votes), answered by Mr.Wizard (8 votes)
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[What are the requirements for a well behaved indexed variable? Subscript, ToExpression, Downvalue?] (http://mathematica.stackexchange.com/questions/94294/what-are-the-requirements-for-a-well-behaved-indexed-variable-subscript-toexpr)
On writing this answer I needed to call a function, (NonlinearModelFit) with an unknown number of parameters.
We have learned that we should not use Subscript for indexing variables because ...
- asked by rhermans (14 votes), answered by Leonid Shifrin (14 votes)
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[What is wrong with RuleCondition here?] (http://mathematica.stackexchange.com/questions/94413/what-is-wrong-with-rulecondition-here)
Hold@1`5 /. x_Real :> RuleCondition[N@x, True] Hold@1`5 /. x_Real :> RuleCondition[N@2`5, True] Hold@2`5 /. x_Real :> RuleCondition[N@2`5, True] Hold@1`5 /. x_Real :> RuleCondition[N@t, ...
- asked by Chris Chiasson (12 votes), answered by Oleksandr R. (10 votes)
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[\(\tt AddTo\) regression in v10]( http://mathematica.stackexchange.com/questions/94296/tt-addto-regression-in-v10)
As we know we can assign special addition rules to symbols by using UpValues:
ClearAll[mySymbol] mySymbol /: mySymbol + x_ := {mySymbol, x}
They are used when we directly add something to mySymbol
...
- asked by jkuczm (12 votes), answered by Bob Hanlon (6 votes)
================================== Greatest hits from previous weeks: ==================================
[Elegant operations on matrix rows and columns] (http://mathematica.stackexchange.com/questions/3069/elegant-operations-on-matrix-rows-and-columns)
Question
The Mathematica tutorial has a section ’Basic Matrix Operations’, describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...
- asked by sjdh (90 votes), answered by Mr.Wizard (31 votes)
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[What are the most common pitfalls awaiting new users?] (http://mathematica.stackexchange.com/questions/18393/what-are-the-most-common-pitfalls-awaiting-new-users)
As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...
- asked by belisarius (266 votes), answered by Michael E2 (142 votes)
================================== Can you answer these? ==================================
[Interfacing Red Pitaya board with Mathematica] (http://mathematica.stackexchange.com/questions/94493/interfacing-red-pitaya-board-with-mathematica)
I just discovered the Red Pitaya board and borrowed a unit to play during this weekend. Surprisingly I did not find any reference to Mathematica on the Red Pitaya forum, nor did I find any reference ...
- asked by Christian Neel (6 votes)
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[Using NMaximize to get integer results for a fractional programming problem] (http://mathematica.stackexchange.com/questions/94549/using-nmaximize-to-get-integer-results-for-a-fractional-programming-problem)
I have an optimization problem that I am trying to model in mathematica (wolfram cloud, to be precise).
Link to notebook for code described here: ...
- asked by pyrex (3 votes)
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[How to speed up summing a large number of vectors] (http://mathematica.stackexchange.com/questions/94660/how-to-speed-up-summing-a-large-number-of-vectors)
First let me explain what I am trying to do in my code.
Assume that I send a very short chirp (2,000 ms long) into a domain filled with 20,000 particles randomly scattered in the domain.
The ...
- asked by Mahdi Razaz (3 votes)