# 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.

209 views

### Avoid creation of OwnValues when inserting transformation rules into ExperimentalOptimizeExpression

I have a large list of transformation rules that I want to simplify. I find ExperimentalOptimizeExpression works as it gets me the answers. My question is: I ...
148 views

### How to avoid restart during development? [duplicate]

Possible Duplicate: How do I clear all user defined symbols? During package development things get messed up quite often. (especially when playing with notations) Is there a simple way to ...
87 views

### Do structures - listing iterated values

Please excuse the crudity / simplicity of this question, hbut I have never really got on too well with Do structures - perhaps I don't use them enough - perhaps I ...
98 views

### Diophantine and odd

need to resolve this Diophantine equation, but with the condition that a, b, c belong to the set of odd numbers from 1-51, as I write this condition in the code ...
195 views

### Problem with Maximize

As $\{p1,p2,p3,p4,p5\}$ represents a probability distribution and $l1,l2$ are the eigenvalues of a stochastic matrix, the function $f$, as defined below, has to be maximized over a certain region. <...
249 views

### Determinant of a random matrix consisting of integers

I am trying to implement a function that finds the determinant of a random matrix consisting of integers. This is the code I have written so far, but I am stuck. Suggestions ? I want to find a ...
87 views

### Calculating the angle between the line joining two points and the x-axis [closed]

I need to calculate the angle between two points, the returned result should between $0$ to $2π$ and getAngle[point1, point2]==getAngle[point2, point1]. I have ...
71 views

### Mathematica Code Involving For Loops Not Completing All Iterations [closed]

First of all, thank you for taking the time to read this. I'm working on a portion of code related to the genetic algorithm that is not producing the expected results. What the code is supposed to do ...
73 views

### How to output (anything) if any error happens

I have long code which goes through iteration process. some times I get error messages. I want to get the iteration numbers (or any kind of output indications) when errors happen. for example, how ...
829 views

### What is wrong with this Cobweb plot [closed]

Something is wrong with my cobweb plot code but I couldn't figure out where do the mistakes come from. So basically we have the iterative map $x_n == x_{n-1}^{2} - 3 \mu$. I would like to draw a ...
126 views

### Where do those nulls come from? [closed]

I have seen discussions of unwanted nulls in the output in the context of building lists with conditions on the elements, but that is not involved here. I would like to know where the nulls come from ...
795 views

### Basic Dynamic Interface Programming that returns variables to nb functions

I have a dynamic module that contains some basic PopupMenu's and Buttons but also need to use the variables returned from these buttons and PopupMenu's in my nb functions outside of this DynamicModule....
339 views

### Graphics copy paste

Background. I have a function ( stored in a package ) that creates 2D graphic images, its prototype looks like this: ...
80 views

### Finding and plotting a parametric solution to a complicated equation (transcendental, log-polynomial)

I am trying (desperately) to find a way to solve a transcendental equation whose solution $x$ depends on non-numerical parameters $a$ and $b$. And then to produce a ...
303 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 ...
335 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. ...
114 views

### Conditioning on group of functions

I have two sets of functions which I want to implement them in a single function with an option indicating which set of functions should be used. Suppose that I have two lists like:(updated example) ...
81 views

### How can i execute several Commands in one text file and use it in notebook?

I want to execute several commands in one text file and use it in notebook by Get[] command. for example: ...
412 views

### characteristic polynomial based on differential equation

I have this differential equation: $$\ddot{x}-\frac{1}{6} \dot{x} - \frac{1}{6}x = e^t$$ When I DSolve it looks like this: ...
400 views

### Finding resolution of an optical system using Rayleigh criterion

I want to use the Rayleigh criterion to find the resolution of an optical system. I have two functions f1 = Sinc[x]^2 and ...
328 views

### How can I improve my code with efficient mathematica built-in functions?

I have written a module for my assignment like below. V[n + 1] = rk[x[n], y[n] ,z[n], V[n]]; vs = V[n].V[n+1]; V[n + 1] = I want to modify it with efficient ...
486 views

### How can I make many runs of a simulation and plot all the results with one expression evaluation?

I have many cells, starting with this first cell: ...
142 views

### FE`symbols that remain in notebook internals even after removing them and SaveDefinitions->True issue

How does one clear the notebook from symbols that remain in it after an edit session?
51 views

### Constructing a root solution diagram (not to tell bifurcation)

Suppose I have a third order equation depending of one parameter say .5 4 x (1 - x) (x - .5) - .5 m x^2 where m the parameter. Obviously there are 3 roots for ...
55 views

### FullForm and the attribute HoldAll

I have noticed that TrueQ @ (And @@ {False, True, True, True}) gives False and, on the contrary, ...
105 views

### Import Tex's aligned multiline equation into Mathematica

I know there have been answers to similar questions, using either ImportString or ToExpression, however I haven't been able to succeed in importing this. I'm using version 10 Mathematica on Linux by ...
82 views

### How to implement the for loop to replace text strings or texts?

I wonder define a bunch variables named like $X_1$, $X_2$, $...$, $X_n$. Is there some smart way to declare them instead of by pure typing. One trick I can image is to use the for loop,...
164 views

### Iterating FindRoot to solve a differential equation

I am new to Mathematica style programming, better at traditional programming. I would like to know if I can create a table of results using FindRoot, where the ...
87 views

### Setting up a system of equations for solution

There are two lists as follows: ...
239 views

### How do I find the nearest city out of a list of cities?

I am trying to find the next closest city to city 1 and want to use a certain radius to check what is the closest city I'm trying to create an algorithm for a TSP. Does anyone know how to implement ...
70 views

### Elegant ways of solving this file batching task

There are a batch of data files in a folder (dir = "D:\\Documents\\datadir"), each of which consists of a list of data items, one per line. Each data item is a pair ...
94 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 ...
745 views

### Obtaining the envelope of an oscillating function and perform fitting

There is an elegant way to obtain the envelope of an oscillation function explained here http://mathematica.stackexchange.com/a/27854/15966 My question is how to modify the code below so I can fit ...
118 views

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1k views

### Getting imaginary data from known real data using Kramers-Kronig relations [duplicate]

Possible Duplicate: Kramers-Kronig in Mathematica I am trying to get epsilon2 (imaginary part) from known epsilon1 (real ...
97 views

### How to overload the operator “*” as KroneckerProduct [closed]

Can I use the expression below a * b * c * d for short to instead KroneckerProduct[a,b,c,d] automatically when a,b,c,d are ...
40 views

### Looping over a function with several parameters

Folks I am a beginner in Mathematica and have a simple question regarding loops: Here's the problem, I have a dataset of with four columns and I need to loop over each row. So the matrix in which my ...
48 views

### Experiment to test Infinite monkey theorem [closed]

I need to apply this experiment: For all numbers between [0,128] let be t {set total=0 repeat this experiment n times {set start=0 choose random number [0,255] lets be R While(R!=t) {...
62 views

### How to use Do and NestList combine?

g[x_]:=((i - 1/i)*x + (1/i)*(x/2))/2; I want to find the following list NumberForm[NestList[g, 0.8, 20], 16]; But don't ...
29 views

### How to select bottom three “norm” values and their corresponding matrices? [closed]

I calculated five random matrices of 6x3 (with some code which is already working) having name Subscript[randompop, j].Here is the output ...
81 views

### How can I calculate the root of any order of power series

How can I calculate the root of any order of power series with Mathematica. Here I insert every quantity by hand. But I want to give a, ...
83 views

### Flipping random elements in a matrix

I'm still a beginner with mathematica so maybe the solution is obvious, but for some reason my code that worked fine earlier doesn't work now. I haven't changed anything about it. I've restarted ...
46 views

### Results of a function are different when the function call and subsequent statements are evaluated one line at a time

I have some code that I am porting from VBA to Mathematica. The original code processes data on an Excel spreadsheet. In Mathematica, I find it convenient to replicate the Excel spreadsheet data ...
193 views

### Finding CPU time of more than one expressions

I want to find the computational time (CPU time) of my code. When I use TimeUsed or Timing commands they give the CPU time of ...
213 views

### Is it possible to build/simulate/extract data from a System Modeler model completely inside a notebook using the MathModelica language syntax?

See examples in: http://www.mathematica-journal.com/issue/v10i1/contents/MathModelicaPaper/MathModelicaPaper_2.html It seems to be ruled out by the statement (Chapter 2 intro): "The subset of the ...
156 views

### Improving code for comparing and modifying nested matrices

I have a matrix such as: ...
349 views

### Using Findroot within a loop

I am trying to get solution to an equation in a loop. The isolate equation works ...
151 views

### How to save the results in an identical Excel file (.xls) in each iteration of a Do loop

Assume the following code (Below code is just an example to clearly illustrate my problem): ...