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.

67 views

errors in simple for loops

Im trying to run the following code, which I have translated from Matlab. I created a for loop nested inside another for loop. mW is a matrix, and ...
220 views

Nested function with an increasing argument

If, for example, I have a nesting function like Nest[1 + x^n (#) &, 1, 3] it gives the result ...
99 views

How to find alignments of interlocking shapes?

I'm searching for the ways to align interlocking shapes, that is, finding the locations and rotations that maximize the arc length at which they touch. For simplicity, I'm assuming 'shapes' are one ...
80 views

How to find line error in init.m file?

I have been changing my init.m user file. It runs fine, but I do get this error below. What does it mean by line 55? What constitutes a line? Are lines separated by "," or ";" or both? Or is it ...
190 views

How to check and reset the boolean value of many options one times?

I defined a function which owns many options. In addtion, these options have a common characteristic. Namely, only accepting boolean value True or ...
78 views

union several arrays of same flag(date for example) efficiently

Suppose I have several arrays from data files which look like: arrayi = {{datei1, xi11, xi21, ...}, {datei2, xi12, xi22, ...}, ..., {datein, xi1n, xi2n ,...}} ...
151 views

SubsetQ[] without ignoring duplicates

How could one create a code that checks whether a set is a subset of another, but not ignoring the duplicates? For example, $\{1,1,1\}$ would be a subset of $\{1,1,1,1\}$, but not vice versa. ...
134 views

Mean squared displacement of a single trajectory

I have a single particle trajectory and would like to calculate the mean squared displacement. The particle is moving from blue over yellow, green to red data points. The {x,y} data are available ...
5k views

Is Mathematica worth it for me?

I'm 13 years old and in 7th grade. I'm currently in Algebra 1, and I have fallen in love with both math and programming. When I came upon Mathematica, it was awesome. My two favorite things fused ...
791 views

Line by line code development

One main advantage of Mathematica over several other languages, at least in my view, is that you can create your code line by line. This makes much easier to debug your code during the development ...
156 views

How can I do a Do While loop [duplicate]

Many languages have a Do While loop, how can I do one in Mathematica ?
143 views

Tips to write more readable code [closed]

What are some tips to write a more readable code? For example in C, tab is your friend. You can also declare variables in a way such that you can read the code easily later on. In Mathematica, if ...
48 views

Incorporating sophisticated constraints on the approximating function into NMinimize

Following the approach as given in the answer of Belisarius here I just wonder how one could incorporate some more sophisticated requirements on the approximating function. Suppose the approximating ...
187 views

FindFit and NMinimize to fit a parametric model (minimize the distance of two curves)

I am trying to find a fit to the cumulative distribution of a set of points using FindFit or NMinimize. In particular, I would like to find the parameters of the cdf of the Beta Distribution that ...
227 views

Avoiding copies when modifying lists

Consider the following approach to modifying a list: ...
124 views

Efficiently generating plots from lists of differing lengths

I guess this is more of an informatic question. A quite complicated function of mine generates me a list of valid points, depending on a parameter, like this: ...
88 views

Double For loop problem [closed]

I am not really sure how to post my original data here, because the Tables I am using are rather big - too big to copy them here. I will try to describe what the problem is. I have three separated ...
77 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,...
124 views

Way to generate all multisets

I have a set $\left\{\{1,2\}, \{3,4\}, \{5,6\}, \{7,8\}\right\}$ (for example) and want to generate all sets of $n$ elements with repetition but without counting the same multiset twice. So I want my ...
145 views

Examples of a large Mathematica construction? [duplicate]

I'm pretty new to Mathematica, and in trying to find examples of good Mathematica programming, it always seems that solutions to a problem can be solved with hardly any lines of code. Of course this ...
103 views

How to write or extend operators like $*\!\!*$

I'm stuck on trying to define simplification rules for NonCommutativeMultiply, much like ExpandNCM found in Documentation Center, under Applications. For example, I'd like ...
178 views

Average positions in a 1D random walk

I wrote this to simulate m random walks of n steps ...
164 views

Code for Newton's Method [closed]

I'm trying to write a program for finding the root of f(x)=e^x+sin(x)-4 by Newton's Method but I'm instructed to not use the built in function and write the code from scratch. I'm pretty new to this ...
135 views

How can I plot the normalized distribution of the Riemann zeta zeros?

Given a list of eigenvalues or a list of Riemann zeta zeros, how can I plot this famous plot found here: On the page referred to, You need to click on "Programs", "The Riemann zeta function" and "...
218 views

What is the equivalent of FORTRAN 77 COMMON BLOCK in Mathematica?

I am in the process of converting a FORTRAN 77 program to Wolfram Language. I have several COMMON BLOCK statements in FORTRAN 77. My question is how to deal with them in Wolfram Language? My ...
87 views

Formulate an equation to find a fixed point [closed]

I have the following equation: Subscript[x, n + 1] = Subscript[x, n]^2 + c with Subscript[x, 0] = 0. This equation is restricted ...
82 views

My program to model exterior ballistics doesn't doesn't produce the plot I expect

Here is my program to model exterior ballistics. It doesn't doesn't produce the plot I expect. How can I fix it? ...
81 views

Dynamic array in Mathematica like malloc in C++

I have a table to describe a crossroad. Each traffic line has it own Q(flow), V( speed) and direction. I'm saving data in array, which hardcoded (very simple code data = {{66, 55, 3}, {44, 33, 2}, {...
36 views

ReplaceAll - Position of list arguments not displayed properly [closed]

This code A[1, 2, 4, 5] /. A[a___] -> Position[{a}, 4] return {} Why this code not return 3 (a position of number 4) ? I ...
66 views

How do I get the last three vectors to complete this cube?

Looking at this file, what vectors do I need to add to the cube:={...} in order to get a full cube?
82 views

Findminimum fails in loops

Introduction to the problem: the function F[x][u,v,w] I'm currently dealing with a very strange minimalization problem. I have a function F[x][u,v,w] which is ...
182 views

Name rewriting for Function fails in closure

At its heart, Mathematica is a dynamically scoped language. While the choice of dynamic scope for Mathematica is very much a defensible one, lexical scope is too useful to do without, and Mathematica ...
40 views

Could not access a specific element of ConstantArray, why ? partw error [duplicate]

I could not access a specific element of ConstantArray, why ? The following is piece of my code: ...
121 views

How to remove a LocalSymbol (or CloudSymbol)?

In version 10.2 LocalSymbol can be used to create a persistent store of a variable. Once this is created I don't see a method to remove it. How are are they ...
102 views

Best practices, tools, and snippets for manipulating notebooks, cells, packages, and help access? [duplicate]

Where is the best place to find/submit lists of Wolfram Language/Mathematica best practices, idioms, and patterns, perhaps grouped by topics? I'm personally interested in those that involve using ...
49 views

system.dllnotfoundexception unable to load DLL“ .dll”: can not find corresponding module

There are two computers. One of them works correctly, whereas the second one writes an error system.dllnotfoundexception unable to load DLL" .dll": can not find corresponding module in Wolfream....
202 views

How can we accommodate arbitrary Unicode characters in symbol names?

I understand why Mathematica doesn't the support the [ character in symbol names, but it should be escapable in some way, like non-printable characters are in ...
79 views

ListPlot dynamical problems [closed]

I have Manipulate, where there are FileNameSetter(to load file with data points) ...
346 views

Plot[f,{x, xmin, xmax}], where xmax is not a const

I have a graph of the function, as in the picture. Function can be set manually, but after a certain value, it is 0. Could I find this value to put it instead of xmax=1 in Plot in order to avoid ...
154 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 ...
170 views

Translate C++ in Mathematica 10.0.2 [closed]

By translating the following program written in C ++ ...
143 views

How would one return from a place of a pure function's body using Return?

From previous answers, replies and discussions it is known, while not formally documented (even in the most recent Wolfram Language Documentation Center), that Return can be used in a two-argument ...
76 views

How would one set up a conditional to evaluate at the last output value (wondrous numbers) [duplicate]

I know this is pretty fundamental, but I'm trying to learn Mathematica on my own and this is stumping me. I know 5 is wondrous and it takes 5 steps to reach one, but I can't figure out the input to ...
281 views

I change a single constant and the simple script suddenly takes forever to complete

I writed a code to display the Dragon Curve fractal, and I reached my goal. The algorithm works by taking the previous two points and then adding the following one by making a 90 degrees turn left or ...
500 views

How to generate a closed B-spline curve?

I wrote a function called deBoor using the Cox-de Boor algorithm to generate a B-spline curve. ...
53 views

Get Domain resp. implicit piecewise definition of numeric Function

Given the following quintic polynomial ...
136 views

Can I code a conditional jump between cells in a notebook?

How can I code the Mathematica equivalent of the following pseudocode: if[condition] ... goto[label_1] ... else goto[label_2] where ...
101 views

How can I wrap a C++ object in WSTP?

I am trying to wrap a sophisticated C/C++ API in Mathematica using WSTP, but can't work out how to return a pointer to a C/C++ data structure. This object was created on the C/C++ side of the wrapper, ...