This tag is intended for the review and improvement of style for already functioning code. It not meant to change the objective of the code.

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10
votes
1answer
373 views

How to visualize pattern matching process?

I want a function that does the same job like ReplaceRepeated, and can make the matching process visible. I searched the Internet but didn't find any existing code ...
6
votes
2answers
194 views

Efficient Lloyd Sampling of Images

I want to sample a grayscale image so that every voronoi cell contains approximately the same total intensity using lloyd sampling. My current code is kind of slow and I was hoping for some advice to ...
1
vote
1answer
59 views

Is this caused by meomory usage ? (Something odd/hard to describe)

I really can't make a "smaller" example, but the files are here, for the data and for the notebook. It will cost a LOT of memory, up to 30G of RAM (maybe more). Here is the problem, (from a Linux ...
3
votes
3answers
1k views

Using DSolve to solve for x[t,parameter]

I'm trying to solve an ODE with two independent variables (a cannon firing from a cliff incorporating wind resistance dependent on velocity). I've tried the following for the x-component: ...
0
votes
0answers
56 views

How to Fold (FoldList) this in a more compact (efficient) way?

Example code: x = Table[something[i], {i, 5}] Table[Fold[f1[#1, f2[#2, a], a] &, x[[i]], {c1, c2, c3}], {i, Length[x]}] This above is just an example. I ...
1
vote
1answer
140 views

How to rewrite a nested loop with Reap and Sow [closed]

I was wondering if anyone know how to rewrite the following nested loop but using Reap and Sow. I need to reduce the execution time. Thank you. ...
5
votes
2answers
405 views

Code elegance and compactness. Help needed with Map, Apply

I need some help with code optimization and compactness. I have a set of two-dimensional points and I can use the Mathematica function FindClusters to find 4 clusters. I'd like to plot the points ...
4
votes
2answers
195 views

Generate lists that satisfy a condition in an efficient way

The following code produces lists of sublists with maximum length 5 that shuffle zeros around an ordered list (here {1,2}). It produces all permutations while ...
1
vote
1answer
273 views

Lookup construction using data matrix and Reap/Sow versus AppendTo`s

I am a user of MMA9 and made my own kind of Lookup, which is now a standard command in Version 10. In my program there is a section in which by means of a StringReplace[ ]-command containing a lot of ...
1
vote
0answers
84 views

Am I simulating correctly my hidden markov chain?

I want to simulate a hidden markov model, in which $y_t|y_{t-1},x_t=i \sim N(\theta_0y_{t-1}+\theta_i,\sigma^2)$, where $y_t$ is the observations or data, and $x_t$ is the state variable of the ...
1
vote
0answers
60 views

Problem with converting recursive code to iterative

I am trying to convert a snippet that uses recursion into one that uses iteration for drawing an L-tree, but my code produces duplicate points. How do I avoid generating them? Recursive version: ...
1
vote
1answer
112 views

Plot multiple solutions [duplicate]

I want to plot multiple solutions of an equation, so that one can differ them in the plot. The given equation is e.g. ...
0
votes
1answer
209 views

Optimizing Chi-square distance between two distribution

I want to program the chi-square between two distribution Xu and Vu with length N. This function is defined as below: Xu and Vu are real and positive. ...
1
vote
0answers
55 views

Implementing normalization/rescalement from a Tutorial

I'm trying to implement a rescale/normalization as is described in here by mathematical expressions in page 10, and code in the top part of page 16. The notebook is also available here. The objective ...
1
vote
1answer
136 views

C compiler error: the no library could be generated error

I have windows 8, Mathematica 9, and I've just installed Microsoft Visual Studio 2013 with update 3. I'm try to run Compile with the option ...
3
votes
1answer
134 views
2
votes
0answers
55 views

Number recognition in Mathematica [closed]

Suppose that I have a number $n$ with many decimal digits of precision. What is the code to use to get Mathematica to recognize possible closed-form expressions for that number?
0
votes
1answer
95 views

How to compute an integral with 300 digits accuracy [closed]

I'm new to Mathematica and I would like to ask what is the code to use to calculate numerically an integral with 300 digits precision; also, I would like to know what is the right code to use the ...
1
vote
1answer
76 views

Code check: Force simplified inequalities to be of form `expr > 0`

Simplify is a nice fast function that cleans up simple inequalities. For example: ...
3
votes
2answers
120 views

Partition a list dependent on consecutive list values

I have a list of 2D points which I partition every time the distance between consecutive list elements is bigger than a certain threshold. In a second step I select all the lists that start within a ...
4
votes
3answers
1k views

How to fix BodePlot that comes with Mathematica?

I am using Mathematica to go through the examples and exercises on the book Modern Control Systems, 6th edition by Dorf. On page 605, there is a table (Table 8.5) with the Bode plot for several ...
0
votes
1answer
196 views

My Baum-Welch algorithm is very slow. Is it due to Mathematica?

I've also posted this question here, since I'm not sure which community is more adequate for this type of question. I've programmed imperatively the Baum-Welch algorithm for a 2 state hidden Markov ...
7
votes
1answer
166 views

Simpler code evaluating Dickman's function?

I've read here that Mathematica 10 can Obtain symbolic solutions to delay differential equations. Would that help in numericaly evaluating Dickman's function $\rho(u)$ ? It is a delay differential ...
31
votes
9answers
5k views

Programming paradigm change

I'm new to Mathematica, I've been learning by myself, and, being a Java developer for some time, it makes it hard to adapt. I've tried to solve a Reddit challenge, and I came up with this solution: ...
1
vote
1answer
117 views

Passing function as argument

I've been mucking around with passing functions as arguments to other functions and via trial and error seem to have something that works. I was wondering if someone could have a quick look at some ...
4
votes
6answers
1k views

Why is this Mandelbrot set's implementation infeasible: takes a massive amount of time to do?

The Mandelbrot set is defined by complex numbers such as $z=z^2+c$ where $z_0=0$ for the initial point and $c\in\mathbb C$. The numbers grow very fast in the iteration. ...
12
votes
2answers
622 views

Parsing a CSV file using Interpreter

The new Interpreter functionality in version 10 looks like it has the potential to make parsing custom data formats very easy. I'm trying to create a CSV parser. ...
0
votes
1answer
186 views

Better code for two variable fractal interpolation functions

I am trying to write code for 2-variable fractal interpolation functions using two iterated function systems and two starting functions (both $y(x)=x$) which creates a sequence of piecewise defined ...
4
votes
3answers
235 views

Is there something wrong with this piece of code involving Manipulate?

I am playing around with the Manipulate sentence. I think the following code is right, and actually Mathematica 9.0 doesn't return any error message, but I am ...
1
vote
1answer
84 views

GUI->Text code conversion

I have to solve about 30 symbolic equations simultaneously. Mathematica is taking more than 24 hours to solve it on a 6 core system and now I have to run that on a cluster. In order to do so I need to ...
7
votes
1answer
298 views

Porting code from MATLAB

I'd like to switch from MATLAB to Mathematica for my research in digital signal processing. I used Mathematica a lot during the '90s but I haven't used it since then, so I might as well be a complete ...
1
vote
1answer
67 views

A code deal with Lists operation ---Needs optimizion

I have written some code to deal with lists, But the speed of the code is slow, Could Someone help me to speed up it? Probably could rewrite it with Functional Programming! Give me some ideas! The ...
0
votes
2answers
136 views

How can I name and manipulate several Input Fields? [duplicate]

I am completely new to mathematica--and have a very basic knowledge of programming. I would really, very much appreciate it if someone could explain to me how to refer to values entered into specific ...
2
votes
1answer
159 views

How can I rewrite my code to make it simpler?

Two months ago,I written a function IRobot to caculate the $I_{xx},I_{yy},I_{zz}$ and $I_{xy},I_{xz},I_{yz}$,shown as below: ...
8
votes
1answer
178 views

Extract what symbol is set by SetDelayed, Set, TagSet, UpSet, SetAttributes, etc

One of the recent features of the Mathematica Plugin for IntelliJ IDEA (www.mathematicaplugin.halirutan.de) is a Structure View which let's you see information about several definitions that are done ...
1
vote
0answers
118 views

How to tweak the following purely numerical code

I am using the following numerical function in my program and I would like to speed it up. ...
0
votes
1answer
131 views

Dealing with nested lists

This question is strongly related to: Map and Apply a function on a nested list I am in a bit of a rut in terms of my MMA skills and looking to improve my coding. I've realized that rather than ...
11
votes
2answers
627 views
0
votes
1answer
90 views

Generalizing Characters to n-character substrings [duplicate]

I'm doing some frequency analysis on an encrypted plaintext. Tally[] and Characters[] make the basic task quite easy. To count the number of times each character appears (sorted alphabetically; ...
6
votes
1answer
141 views

Path construction using `Nearest` shows ill behavior?

I have a dataSet that I'm trying to sort choosing a starting point and going to its nearest neighbor, and then to its nearest neighbor and so on. To do so, I've ...
2
votes
1answer
136 views

Performance on Binomial Deviate is slow

I hope I won't get spanked for reposting. This is related to a previous question discussed here: Performance on Multinomial Deviate is slow. but this version is simpler because it is a binomial ...
0
votes
2answers
86 views

Multiplying a list and randomly re-assigning that list to a series of numbers

I'm trying to write a script that matches a particular element to a coordinate. Let's say there are 24 coordinates; and that fractionally a:b:c:d:e is 18%:18%:18%:18%:27%. Instead of matching 4 of a, ...
7
votes
3answers
463 views

Mathematica style (drawing cubes)

I wanted to draw (lattice-aligned) unit cubes inside a sphere with a given radius centered on the origin, so I wrote this program: ...
0
votes
2answers
170 views

How can I improve Do loop?

I have very large input of time series data (over 30000 observations) that look like as follows: ...
0
votes
0answers
34 views

Check if a (possibly nested) list is real [duplicate]

I have a very large matrix of numbers. I want to check if all its entries are real. At the moment I am using realQ = And @@ Thread[Flatten[Im @ #] == 0] & Is ...
2
votes
1answer
110 views

Writing a function to mimic Characters

I am working my way through Programming Paradigms via Mathematica (A First Course) and have answered the following question in lesson 25: Write a function of one argument "s", a String, which ...
1
vote
2answers
203 views

Discretizing data using quantiles in Mathematica

I am trying to discretize a long array of real numbers into a uniformly distributed integer array. To do this I am identifying the quantile where each real value sits and writing it out to the output ...