An algorithm is a sequence of well-defined steps that defines in abstract the solution to a problem.

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Maximizing the number of zero entries in a matrix

I have a matrix with a bunch of parameters in its entries, they all come in different combinations in different places of the matrix. I can post the matrix itself if requested, but I think what I mean ...
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88 views

Implement a piecewise function elegantly and efficiently

Given that $$ g(x)= \begin{cases} max(x_{min},x-m) & 0.5x \leq max(x_{min},x-m) \\ 0.5x & max(x_{min},x-m)<0.5x<min(1,x+m) \\ min(1,x+m) & min(1,x+m)\leq 0.5x \end{cases}$$ ...
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Challenge: Speeding up MaxDetect for application in 3D blob detection

In image segmentation it is a common problem that objects appear clustered and are therefore undistinguishable from each other when using simple algorithms. Based on this post I obtained efficient ...
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149 views

Using mathematica to discover algorithms?

In Steven Wolfram's blog entries, he discusses using mathematica to discover algorithms. I have tried several different google searches for papers on such topics, and have found none. I suspect this ...
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311 views

Counting paths of a certain length between a source and sink vertex

I have a graph $G$, which may be directed or not, and I was wondering if there was an efficient way of using, say, BreadthFirstScan[] and FindShortestPath[] to count the number of paths between some ...
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307 views

A* algorithm for finding shortest path in a graph

FindShortestPath finds the shortest path between two vertices in an edge-weighted graph, allowing a choice between the Dijkstra and Bellman-Ford algorithms. In my (limited) understanding, both of ...
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366 views

Solving recursion relations using Mathematica

I want to solve the recursion relation given in equation 2.7(a/b) on page $6$ of this paper. (..the initial seed is $F_1 = G_1 = 1$ and the functions $\alpha$ and $\beta$ are defined on page $5$ in ...
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42 views

How to compute the longest non-contiguous common sequence?

LongestCommonSequence[] works well, but what about finding the longest common sub-sequence (not necessarily contiguous)? Is this function built in to the genome ...
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177 views

Fast calculation of commute distances on large graphs (i.e. fast computation of the pseudo-inverse of a large Laplacian / Kirchhoff matrix)

I have a large, locally connected and undirected graph $G$ with $\approx 10^4$ vertices and $\approx 10^5$ to $\approx 10^6$ edges. Moreover I can bound the maximum vertex degree as $Q_{max}$. I ...
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50 views

Implementation of Lubaehevsky-Stillinger Algorithm to pack hard spheres

To generate a model of a polycrystalline material with specified grain size distribution (e.g coming from a Monte Carlo Grain Growth simulation) the Paper "Effects of grain size distribution and ...
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71 views

How can I detect certain letters by shape in an image?

I have a website where people can post Flipbook animations, called Flipnotes. Unfortunately, most of the Popular flipnotes are in the following categories: MV (Music Video) AV (Audio Video) AMV ...
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109 views

What's a non-trivial Mathematica program involving conscious choice of stack vs. queue data structure?

In a typical computer science algorithms course, much attention is given to the discussion of queues vs. stacks as a data structure programmers need to consciously choose from to achieve algorithmic ...
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48 views

How to determine three last bindings made to a variable when evaluating an expression?

How can I create a list of bindings made to a certain variable when evaluating an expression? I want to determine three bindings made.
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78 views

How to recursively check is a graph is a binary search tree?

I'm having trouble using the built in DepthFirstScan[] to see if a tree satisfies the binary search tree property, the documentation is confusing. Motivation: I'm ...
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143 views

Spectral Clustering

I am interested in the following question: How is it possible to check whether an algorithm is working properly? However, this question is too general for the post and I'd like to restrict attention ...
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50 views

What Algorithm Does Mathematica use to Calculate Betweenness Centrality for Unweighted Graphs?

Recently asked this question http://math.stackexchange.com/questions/888369/betweenness-centrality-how-long-does-mathematica-take on the Mathematics SE. Does anyone know, as a follow up, what ...
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120 views

how to write my own interpolation method

I was comparing results of spline interpolation in Mathematica and C++/gsl-library Results of interpolation are different if I use: ...
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197 views
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Independent Set Sorting

Let's say I have a graph g, and I wanted the largest independent vertex set of g. I would write then, ...