Questions on finding existing Mathematica implementations or expertise to address a clearly stated problem.

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2
votes
1answer
215 views

How to make hollow Graphics3D?

I keep seeing a notebook to use of Mathematica as a 3D Printing tool (e.g.: this link). In the notebook on slide 8/11, we find these pictures: I'd like to design it as such that, but I don't ...
5
votes
4answers
210 views

Functional way to Climb an Association Decision Tree

Associations are nice tool to create decision trees. Here is a toy example of how I'm starting to use it: ...
2
votes
1answer
638 views

How to implement the directed Barabasi-Albert algorithm in Mathematica?

Does anyone know how to implement an efficient version of the [directed Barabasi-Albert algorithm][1] in Mathematica that scales until hundred of thousands nodes? The directed network mechanism is ...
3
votes
0answers
85 views

Is there a way to do a symbolic PLUR decomposition of a matrix? [duplicate]

I am looking for a way to achieve the PLUR decomposition of a maitrx, as given in this paper here. The equivalent syntax in Maple is: ...
1
vote
1answer
667 views

Getting code from the Wolfram Demonstrations Projects [closed]

I saw from mathematica's website, there is a fantastic project about the 2D Riemann Sum. Riemann Sums For Functions of Two Variables I want to see the similar effect in my Mathematica (with ...
0
votes
1answer
178 views

Sum Over Multiple Indices part 2 [duplicate]

Recently I asked this question as I was trying to see how to write a particular Identity. I asked about how to write the following sum: ...
3
votes
3answers
776 views

Sum over multiple indices

I would like to be able to enter the following left hand side of an identity. I can write the right hand side (i think) but am not sure about the left. The Left hand side is ...
1
vote
2answers
455 views

DSolve bvlim error due to Boundary condition at infinity

I am solving an Ode using Mathematica that has boundary condition at infinity which is why Mathematica is showing error message. Please help to tackle this problem. ...
8
votes
1answer
449 views

How to create a Poincaré disk type kaleidoscope in Mathematica?

Creating a kaleidoscope in Mathematica is not a new topic at all, examples can be found from the links like Wolfram reference and Wolfram demonstrations. My question is how to create Poincaré disk ...
1
vote
3answers
97 views

How to distribute but skipping one level

I would like to write a Rule that mimics built-in Distribute[], but one that distributes ...
5
votes
0answers
159 views

Finding quasi-cliques

What is the best way to identify quasi-cliques in a graph in Mathematica? I don't think it has been implemented, so are there any solutions to do this? Or do I have to export the graph data somehow ...
0
votes
2answers
83 views

How do I tell pattern searcher the order in which to search for patterns given in general form?

I have a really long sequence of Symbols inside a function, say nonCommute[a,b,c,e,e,f,g,b,i,j], and I am implementing a ...
2
votes
1answer
61 views

Searching for symbol except within subexpressions with a particular Head

I would like to write a searcher like FreeQ that looks for a Symbol (or Head) in an ...
55
votes
1answer
1k views

DumpsterDoofus's captivating generative art

How can I render these beautiful images that DumpsterDoofus posted?
3
votes
1answer
136 views

Solving a system of generated equations?

I would like to generate a function in the following form, where the number of terms can be specified arbitrarily: ...
4
votes
3answers
856 views

Computing Gaussian curvature

Can Gaussian curvature $K$ be computed from WolframAlpha or any other available Mathematica program? Please indicate the program or its reference. If input ...
28
votes
2answers
3k views

How to build a bvh (a motion capture file format) player in Mathematica?

How to build a bvh player that can be used to visualize human motions in Mathematica? Any idea or sample code would be appreciated. ...
0
votes
0answers
117 views

Converting code from Matlab to Mathematica [duplicate]

I have the following piece of code: ...
2
votes
6answers
182 views

Setting the elements of a list equal to elements of a different list

A = {a,b,c,d,e,f,g,h} B = {1,2,3,4,5} How would I go about setting some of the elements in list A equal to the elements in list B and then the left over elements ...
4
votes
3answers
143 views

Help with coding triangular nodes/elements

I'm trying to write a program where it will shoot out the triangle node numbers. For example, in the picture, if we choose to divide this triangle by 5 points, then the program will return out the ...
20
votes
4answers
3k views

Convert spectral distribution to RGB color

Presume I have a spectrum as a function of wavelength (an example being the blackbody spectrum): I want to convert that to a single RGB color to display on-screen, i.e. the "color" of that object ...
6
votes
2answers
403 views
8
votes
1answer
564 views

How to generate nonperiodic tilings?

I need to generate nonperiodic tilings which are similar to the attached figure (kite-domino tiling). I was thinking the code is similar to the code for the Penrose tiling. However, that code is too ...
4
votes
0answers
135 views

Linearised Einstein equations

I need to compute the linearised Einstein Equations around a fixed metric $$g_{μν}=\text{Minkowski metric} + h_{μν}$$ which is not the flat metric. Does anyone know a Mathematica package or a ...
6
votes
2answers
840 views

Distribution of 10 points within a unit square

Related to some packing problems, following problem arose: Distribute 10 points within a square of sides 1, so that minimal distance between them is maximized. With the help of random simulation, or ...
27
votes
4answers
5k views

How to create effect like Van Gogh's stroke brush?

I need to apply Van Gogh's stroke brush effect to a random image Take the following image as an example: Thank you so much if you could help!
15
votes
4answers
1k views

List comprehension in Mathematica

Python supports a concept called "list comprehensions". Following is sample example ...
5
votes
1answer
807 views

How to implement Kemeny-Young method? (rank aggregation problem)

Prehistory I am trying to make some statistical analysis of some experimental data, arises from measurements made ​​on an ordinal scale. I faced with the problem of rank aggregation: to get from ...
5
votes
1answer
494 views

Linearized Einstein Equations with Mathematica

I need to compute the linearised Einstein Equations around a fixed metric $g_{\mu \nu}$ which is not the flat metric. Someone knows any Mathematica package or a review that can help me?
0
votes
3answers
513 views

Differential equation of mass spring system with compliant stoppers

I would like to solve numerically the differential equation for the displacement x[t] of a mass m-spring ...
15
votes
3answers
1k views

How can this type of optical illusion be created in Mathematica?

I see these around the web and would like to make them in Mathematica. Combining them in an array is actually quite mesmerizing!
4
votes
1answer
2k views

How do I hide some of Input

I have a project with a friend, and we make some work in Mathematica. He is not very good at Mathematica, and I have made some long necessary formulas we need. I would like to show what I've made but ...
10
votes
3answers
1k views

Extract connected components from PNG image file and write to individual PNG files

Given the PNG image below with the three leaves in it, I'd like to extract each individual leaf and write it to its own PNG file, using Mathematica 9. Note that in the original image, the box bounding ...
30
votes
2answers
2k views

Playing with Matrix falling code in Mathematica

I was trying to create a Matrix falling code image with Mathematica. Here is my code: ...
9
votes
4answers
571 views

How to set Block local variables by code?

I need to create a user-defined Block function where the Block variables' values are defined by code. For example, imagine I ...
3
votes
2answers
3k views

Faster way to convert real strings into numbers [duplicate]

Working with big files, I have to convert some numbers that are in string format into real MMA numbers. I know that I can use ToExpression but it's slow when ...
7
votes
3answers
3k views

Lyapunov Exponent

Does anyone know a (simple) Mathematica code for computing the Lyuponov Exponent for the Rossler System? Thank you Rossler System: ...
17
votes
2answers
811 views

How to perform fuzzy lookup between lists?

I have two big lists with 10,000 lines each, with product names from different databases. They have a lot of common products (50%), but they are not typed in the same way. For example there is one ...
7
votes
5answers
299 views

Making a table with elements like {10i+j, i, j}

Table[10i+j,{i,4},{j,3}] will generate a table that looks like this: {{11,12,13},{21,22,23},{31,32,33},{41,42,43}} I would like ...
7
votes
3answers
534 views

Composition of mappings not working as expected

I have two functions $f,g:\mathbb{R}^2 \to \mathbb{R}^2$ and I define a third one $h:\mathbb{R}^2 \to \mathbb{R}^2$ as the composition $$h(x,y) = g(f(x,y))$$ I'm trying to get this function into ...
10
votes
1answer
10k views

Mathematica code for Bifurcation Diagram

At the moment I am trying to construct a bifurcation diagram of the iterative function $f(x)=$ $ax-1.1975x^3$. I've scoured the internet for pre-made bifurcation diagrams and found many (mostly of the ...
5
votes
1answer
489 views

Tooltip for a ListPlot3D

I am getting stuck with figuring out how to use Tooltip for a ListPlot3D. Basically I have a list of values for the 3D plot (no ...
39
votes
2answers
8k views

Image Shadow Removal in Mathematica

The task is: Image shadow removal is an important topic in image processing. If you feel curious about it, you may take a look here, or just google for it image shadow removal There are also a ...