6.44 Tuesday, March 3, 2015

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Top new questions this week: 
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[Finding a function that fits the shape of an image]http://mathematica.stackexchange.com/questions/75855/finding-a-function-that-fits-the-shape-of-an-image

How can I find a function that fits the given shape of an image? Or instead extract a point set from the shape and then find an interpolating function fits the shape.

An example image is attached.

- asked by Mikayel (12 votes), answered by belisarius (21 votes)

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[Adding Trace produces error messages]http://mathematica.stackexchange.com/questions/76082/adding-trace-produces-error-messages

This is very strange. As I was trying to debug this problem, I noticed when I add Trace then I get lots of internal errors generated. This also happens the first time after the kernel is started. ...

- asked by Nasser (11 votes), answered by WReach (9 votes)

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[How can I define or use a new coordinate system in Mathematica?]http://mathematica.stackexchange.com/questions/75815/how-can-i-define-or-use-a-new-coordinate-system-in-mathematica

I want to use the dipole coordinate system as defined in this paper: http://arxiv.org/abs/physics/0606044

I see that Mathematica can do all kinds of vector analysis using different kinds of ...

- asked by jvriesem (7 votes), answered by Itai Seggev (0 votes)

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[Inconsistent behavior of undocumented Encode->Import->StringToStream->Get on password-locked stream]http://mathematica.stackexchange.com/questions/76085/inconsistent-behavior-of-undocumented-encode-import-stringtostream-get-on-pas

Let’s save a definition. Encode it with password/key and Get it again.

We will not use Get directly on directory but with combination of Get+StringToStream+Import.

Get works with streams since V9.0 ...

- asked by Kuba (7 votes), answered by Jinxed (1 vote)

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[Ghost trails with Animate?]http://mathematica.stackexchange.com/questions/75936/ghost-trails-with-animate

What are some approaches to integrate Ghost trails methods with Animate, which otherwise seem more suited for exporting individual frames?

For example, given this rootPlot function, how can trails ...

- asked by alancalvitti (7 votes), answered by Pickett (9 votes)

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[how to build matrix from set of vectors and other matrices using ArrayFlatten]http://mathematica.stackexchange.com/questions/76311/how-to-build-matrix-from-set-of-vectors-and-other-matrices-using-arrayflatten

I want to build a 6 by 3 matrix, from the following: one vector is 3 by 1, then a matrix, which is 3 by 2. These will go to the top 3 rows. Now the bottom 3 rows, I’ll have 3 vectors each is 3 by 1. ...

- asked by Nasser (6 votes), answered by Kuba (5 votes)

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[Computing launch parameters for hitting a point in 3D with projectile under influence of wind]http://mathematica.stackexchange.com/questions/75945/computing-launch-parameters-for-hitting-a-point-in-3d-with-projectile-under-infl

The end goal of this problem is to compute functions which describe the launch parameters which are needed to hit a specified goal in 3D in the presence of wind disturbances. This is as far I have ...

- asked by Julian (6 votes), answered by belisarius (7 votes)

================================== Greatest hits from previous weeks: ==================================

[Where can I find examples of good Mathematica programming practice?] http://mathematica.stackexchange.com/questions/18/where-can-i-find-examples-of-good-mathematica-programming-practice

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

- asked by J.M. (333 votes), answered by faysou (308 votes)

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[How do I draw a pair of buttocks?]http://mathematica.stackexchange.com/questions/66538/how-do-i-draw-a-pair-of-buttocks

I’m trying to develop a function which 3D plot would have a buttocks like shape.

Several days of searching the web and a dozen my of own attempts to solve the issue have brought nothing but two ...

- asked by Simpleton Jack (209 votes), answered by mikuszefski (327 votes)

================================== Can you answer these? ==================================

[FindMinimum’s WorkingPrecision behaviour]http://mathematica.stackexchange.com/questions/76259/findminimums-workingprecision-behaviour

I discovered the following behaviour when using FindMinimum for constrained optimization:

Clear@f 
f[x_?NumericQ] := (Print@Precision@x; x^2) 
FindMinimum[{f[x], x < 1}, {x, 1}, WorkingPrecision  ...

- asked by sebhofer (1 vote)

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[Font style in Mathematica and .tex file]http://mathematica.stackexchange.com/questions/76250/font-style-in-mathematica-and-tex-file

I am using Mathematica 8. I want to label the axes of figure in "Times" font.

Plot[Sin[z], {z, -2 Pi, 2 Pi}, Frame -> True, 
FrameLabel -> {"z", "a(z)"}, 
LabelStyle -> Directive[FontSize  ...

- asked by zenith (3 votes)

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[ParametricNDSolveValue over a region]http://mathematica.stackexchange.com/questions/75887/parametricndsolvevalue-over-a-region

I’m getting the following behavior I don’t understand when using ParametricNDSolveValue over a region. You can reproduce the behavior considering Poisson’s equation as shown below

The below works as ...

- asked by user2162855 (1 vote)