Tagged Questions

Questions on writing non-trivial programs in Mathematica. Do not use this tag for questions on plotting/graphics or for questions on doing mathematics with Mathematica, where the focus is more on the math than the program.

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1
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0answers
36 views

Implement a piecewise function elegantly and efficiently

Given that $$ g(x)= \begin{cases} max(x_{min},x-m) & 0.5x \leq max(x_{min},x-m) \\ 0.5x & max(x_{min},x-m)<0.5x<min(1,x+m) \\ min(1,x+m) & min(1,x+m)\leq 0.5x \end{cases}$$ ...
1
vote
2answers
57 views

How do you apply an algorithm individually to an array with many graphs

I have and array with many graphs to which I want to apply an algorithm (below) to each graph in an array that contains all my graphs. ...
3
votes
1answer
76 views

How to use RunProcess to import external function?

I have a functions written in an external language called GO. How can I quickly load them into the kernel for use as Mathematica functions? The two ways I've tried are with MathLink and LibraryLink ...
5
votes
1answer
83 views

How to implement kvo in Mathematica 10? [duplicate]

Key value coding and observing is something that other languages do well, like objective-c for instance. What's the best way to achieve something similar in Mathematica (if at all possible)? That is, ...
1
vote
2answers
41 views

How to get the outermost command evaluated first?

I have an expression like ToString[Stuff[...]]. I plan on having the Stuff[...] be manipulated as a string according to the output of other parts of the program. The problem is that Mathematica tries ...
1
vote
1answer
100 views

For loops in Mathematica [duplicate]

I'm actually the first time using loops in Mathematica. For example, I have: For[i = 1, i <= n, i++, For[j = 1, j <= n, j++, ....] How it is possible now ...
0
votes
0answers
43 views

Find the maximum/ minimum of the function f(x,y,z) = x+2y+3z on the curve of intersection of the plane x-y+z = 1 and the cylinder x^2+y^2 = 1 [duplicate]

How to write the program for: Find the maximum/ minimum of the function f(x,y,z) = x+2y+3z on the curve of intersection of the plane ...
0
votes
0answers
24 views

Calculate number of probabilities [migrated]

I want to calculate a number of probabilities of a+b+c=1 For a vary from 0 to 1 with an incrementing of 0.1 For ...
6
votes
3answers
222 views

Calculating integral by Romberg Algorithm

In my "Numeric Anasyis" course, I learned the Romberg Alogrithm to calculate the numerical integral. The Romberg Alogrithm as shown below: $$ ...
0
votes
1answer
38 views

Symbol appears in multiple contexts when load two packages with unique function names

I have two packages "packageA" and "packageB". The function names across packageA and packageB are unique. No two functions have the same name. When I issue the ...
0
votes
1answer
43 views

Programming a series involving alternative log expressions

This is likely my error but I cannot see it. I define a vector: x1 = {{{2, 2}}, {{2, 1}, {3, 1}}, {{3, 2}}, {{2, 1}, {5, 1}}} If x1[[ i, 1,2]] is 2, I would like to find $(\log$ x1[[ i,1,1]]$^2$). ...
5
votes
1answer
263 views

How to solve this probability symbolically or numerically?

I am trying to calculate the following probability $$\mathbb{P} \big(\sum_{i=1}^{m} (A_i + S_i) \le L < \sum_{i=1}^{m+1} (A_i + S_i) \big)$$ where, $$A_i \sim \exp(\lambda), \quad S_i \sim ...
5
votes
0answers
115 views

How to download and combine S&P 500 stock prices

I want to download historical S&P 500 stock prices and combined them into one big file, having only one column of date referencing all stocks. Here is what I have do so far. ...
15
votes
1answer
266 views
+100

Why does this line increase the consumed memory?

Probably this is a simple question, however I really don't understand this behavior in Mathematica. It particularly leads to a memory leak in a huge program I have to do processing of 3D images. I ...
-2
votes
0answers
19 views

Defining an ORIGINAL derivative function? [duplicate]

NOTE: I do not want to use the Derivative or D functions. – I want to define an original function. I began with this definition of the derivative , which resulted in: Limit[ #, h -> 0] & /@ { ...
0
votes
1answer
79 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. ...
4
votes
1answer
77 views

Slowdown of Flat attributed function

I was trying to write an associative function f using the attribute Flat. ...
1
vote
3answers
104 views

Creating a list of lists as a function of a list

I have a list of length n whose elements are all 1 and -1. For each -1 in the list i want to create a list with a -1 in the same spot and a 1 everywhere else. For example: A list like {-1, -1, 1} ...
0
votes
0answers
61 views

Using Animate/ListPointPlot3D on more than one list

I have a couple orbits defined which have been mapped into one array as shown: ...
1
vote
0answers
58 views

Updating procedural fitting algorithm to more efficient style?

For some time now, I have used this procedural programming approach to fit data in my research that is too cumbersome for the built in Mathematica functions. (Although this simple example works fine ...
0
votes
0answers
22 views

A question about conditional replacement [duplicate]

{g[x, y, z], h[x, y], f[]} /. (f_[t___] /; f != List) :> Plus[t] Why is the output of this expression ...
3
votes
2answers
106 views

RandomFunction and Histograms

RandomFunction[QueueingProcess[3, 5], {0, 15}] Histogram[data, Automatic, "PDF"] gives a very nice way to see the histogram based on the specified process. ...
1
vote
1answer
167 views

How can I call the R-programming packages in my Mathematica?

I am trying to call the R-programming package called highfrequency in my Mathematica so that I can use its function rCov. I ...
4
votes
1answer
42 views

what's the meaning of “-mathlink” as part of Arg for LinkLaunch?

LinkLaunch["MathKernel -mathlink"] LinkLaunch["MathKernel"] The both code line above can launch a MathKernel. What's the difference of them? what's the meaning of ...
0
votes
0answers
16 views

what's the difference between CreateKernelLink() and CreateKernelLink(String Arg)?

I have a .NET program which will connect to MathKernel. When the program runs, there will be a icon of MathKernel on the taskbar. ...
0
votes
0answers
60 views

What is the meaning of //N in mathematica? [duplicate]

As the title says, What is the meaning of //N? i can't remember it.I tried looking in documentaion center, but it came up with nothing. Help appreciated.
2
votes
0answers
69 views

Distance Time Warp (DTW) function implementation in mathematica

The DTW (Distance time warp) is given here http://en.wikipedia.org/wiki/Dynamic_time_warping There is an implementation of DTW in R as well as MATLAB. However i am unable to find something for DTW in ...
1
vote
0answers
53 views

Programming for matrix manipulation

I want to write a programme which operates on nd x nd matrices. The programme looks the matrix as a n x n block matrix where ...
3
votes
2answers
132 views

Why the function cannot achieve the expected result?

Today, I write a toy code (Framed the prime in a list) to practice Mathematica programming ,which as shown below: Trail 1: ...
4
votes
2answers
465 views

How to create a function like in Python

I want to call a function that would perform a function rather than assigning an expression to them. I.e. ...
4
votes
2answers
376 views

Colorize Grayscale Image

I have a grayscale image that contains two objects. The grayscale pixel values can be divided into three intervals where two of them represent objects and the third represents the background. The ...
1
vote
2answers
50 views

Using conditionals to check if LinearSolve found a solution

Is there some way to check if LinearSolve found a solution using conditionals in Mathematica 9? I need to solve a large number of linear equations, but I am only interested in the cases where there ...
0
votes
1answer
99 views

Turning a 2D 3 body problem into 3D not so easy?

I have programmed a 3 body problem, that can in theory work for more than 3 bodies. I apologize in advance for the length of the code that I posted, I don't really know how much one would need to ...
2
votes
1answer
77 views

Image background subtraction using parallel computing

I am developing a program for pattern recognition. I want to use the parallel computing to get a real time application. I have two cameras where each one gives n frames/second. I need to process the ...
7
votes
1answer
89 views

why CopyFile cannot overwrite existing file?

CopyFile return $Failed when the file exists on destination. is there any way to force CopyFile to overwrite the existing one? the way I use now is DeleteFile and ...
2
votes
1answer
82 views

Please explain this while-loop

Code: ...
4
votes
0answers
120 views

Tutorial video on the Wolfram Language [closed]

A 3 hour video explaining the workings of the Wolfram Language is now available at: http://www.wolfram.com/broadcast/s?sx=Gaylord downloading the pdf or notebook here of entire lecture is very ...
4
votes
1answer
107 views

Association and rudimentary object-oriented programming

Doesn't Association provide us rudimentary object oriented programming via constructs like ...
9
votes
6answers
483 views

Best way to find permutation with specific total

Can anyone suggest a good way to find permutations of 12 digits, 0 to 4, totalling 24. I.e. two such permutations:- {2, 1, 4, 1, 2, 2, 2, 2, 2, 2, 1, 3} // Total ...
7
votes
2answers
144 views

Connecting to LeapMotion

Thanks to those who helped me with my previous question. I will help others too where I can. In the meantime I have a general question whether anyone has had success connecting Mathematica to the ...
6
votes
2answers
152 views

Manage a network of Arduinos using Mathematica and xbee

I'm trying to take 5 analog reads from two or more Arduinos at different times. So to do that my listening port via xbee is COM8, then I start a ...
5
votes
4answers
308 views

Is there any way to assign multiple values?

I am looking for something like "byref" assignment in programming languages. Let's assume I have: x1=x2=....=xn if I want to change their values ( say to 3 ) I need to set all of them like: ...
6
votes
1answer
131 views

Where can I put my conditions?

I just learned in this answer that you can put conditions inside a With and thus use computed values in them, like this: ...
7
votes
2answers
284 views

Recursive partitioning: Is there a better way to do this?

Consider the following function, which recursively splits a list into equal length sublists (the length of the list is assumed to be a power of the second argument): ...
6
votes
2answers
252 views

How to transform a matrix to upper-triangular with operation- tag elegantly?

Description: Recently, I have a thought that writing a function to show the transformation process when a matrix is transformed to upper-triangular. My trail ...
1
vote
1answer
123 views

Help in Bifurcation Diagram

My dears, I need to plot a bifurcation diagram for the following non-linear systems represented by the next Mathematica code ...
0
votes
1answer
83 views

How to plot multiple orbits with more than two functions

Using a program given to me (which was designed to have a particle orbiting another of infinite mass), I tried to extend it to the motion of two particles orbiting a common centre of mass. I have a ...
1
vote
0answers
74 views

Elementwise operation, part deux [closed]

There are many answers to this question: which are forms of Mathematica's map, but languages like Scheme (I think also Python in recent years) also provide a ...
3
votes
1answer
211 views

How to use Mathematica for traditional programming

I am new to the structure of Mathematica. I understand that in the notebooks, one enters the symbolic expressions and evaluates them. But I need to generate some simulated data and do that a few ...
3
votes
3answers
68 views

Composing function returning list and function taking multiple arguments

What is the easiest way to compose a function that returns a list of $n$ elements with a function that takes $n$ arguments. If I know this $n$ a priori, I can do something like ...