Questions tagged [programming]

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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3
votes
1answer
66 views

Is it possible to make Decompose work with coefficients containing radicals?

It appears that Decompose works reliably only on polynomials with integer coefficients, although it seems to be not mentioned in the docs. Can I make it work (or ...
0
votes
0answers
44 views

Plotting isocline curves [on hold]

I have been trying to plot this differential equation (-3.98*10^14)/(y*x^2) without any success. I need help.
0
votes
1answer
46 views

Getting unexpected results form If expressions

I'm mystified by this: g[a_, b_, c_] := Module[{d}, d = If[(b < 1), b, b + 1]; If[a < b, d = 0.]; d*c] g[a, 20, 40] ...
0
votes
0answers
69 views

Converting a code with for a loop from MATLAB

In MATLAB I have the following for loop: ...
4
votes
2answers
54 views

Turning Lists of Formulas Into Lists of Ordered Pairs

I'm working with a finite list of linear equations in some amount of variables. Say, {2kx-3y,3y+2kz-x,2x+2y+2z,ky} Is it possible for Mathematica to take this list and output a list of pairs where ...
0
votes
0answers
24 views

Question about converting Mma expressions to TeX

When I want to convert the following expression Integrate[1/(1 + t (-I - 1)) (-I - 1), {t, 0, 1}] to TeX, I do: ...
2
votes
0answers
62 views

How can I make this “Pick” inside a “Table” run faster?

I am working on becoming more and more familiar with MMA and on a scale from one to ten, I would rate myself as a four or a five. I understand vectorization and that loops-are-very-bad. I have ...
0
votes
1answer
68 views

Change a formula [closed]

have a program consisting of a database of colors in L-a-b format. I want a formula to obtain the desired color by mixing different amounts of colors that are in the database. For example: I want ...
16
votes
2answers
291 views

Improving Performance of an XY Monte Carlo

I normally write my Monte Carlo codes in Fortran for speed, but I was doing some quick and dirty work and wrote one in Mathematica for the XY model on a square lattice (see Kosterlitz-Thouless ...
0
votes
1answer
42 views

Assert that prints message and aborts computation?

I'd like to add asserts which check for condition, print useful message and abort computation on failure. IE, ...
2
votes
1answer
55 views

Operate on functions with arbitrarily many arguments

Is it possible to define a function that can operate on another function with arbitrarily many arguments? For example, I want to do error propagation using partial derivatives. It is not clear to me ...
2
votes
2answers
79 views

How to generate vectors with programming

I want to generate all possible vectors programicaly with entrys in $\Bbb Z_4$: $$A_j:=\begin{bmatrix}x_1\\ x_2\end{bmatrix}, \qquad x_i\in \{0,1,2,3\}, j=1,2,\cdots 16.$$
4
votes
4answers
198 views

Programming a recursive formula into Mathematica and find the nth position in the sequence

Well, I have the following recursive formula (where $\text{n}$ gives the position in the sequence): $$\text{P}_\text{n}=\alpha\cdot\text{P}_{\text{n}-1}+\text{P}_{\text{n}-2}\tag1$$ For arbitrary $\...
5
votes
3answers
473 views

Arrange a list in ascending order by deleting list elements

I am new to mathematica and currently learning it by solving some basic problems. I am trying to arrange a list in ascending order using a detailed IF loop. For instance if we start out with $\{1,65,...
3
votes
2answers
86 views

Function with string explanation for its arguments with equal signs [duplicate]

I want to write a function using string as explanation for its arguments so that the function becomes intuitive for new users. For example, I want to write a function to compute BMI (just for ...
1
vote
1answer
94 views

How to use Module function?

Here is my issue; I want to iterate a fit to this data for a polynomial of degree 2 up till degree 6. However, at each iteration I drop certain data points that have a poor residual value. So each ...
3
votes
1answer
31 views

How to add a Locator to a Manipulate / ListPlot?

I have the following Manipulate to graphically show the n-th roots of unity: ...
5
votes
3answers
142 views

Pure functions applied to a two dimensional list

Lets say I have a two dimensional list: list = {{a, b, c}, {aa, bb, cc}, {x, y, z}, {xx, yy, zz}}; and two pure functions: ...
2
votes
1answer
35 views

how to run a specific cell in a notebook from another notebook

I have a long Mathematica code in a notebook, denoted by NB1. Since it is a very long code, and I need only some of the outputs from NB1 to be used in another ...
3
votes
1answer
76 views

Delete elements less than the last largest element

Here is my list. The first column contains its index and second column has data. ...
2
votes
2answers
73 views

Finding Non-Simple Paths of a Given Length on a Graph

For the following graph: ...
1
vote
1answer
98 views

How to Open, Evaluate and Close the same Notebook 100 times in a row?

I have a Mathematica notebook which I Open and Evaluate by hand. It Exports some data and then Closes. I now wanna Open, Run and Close the exact same Notebook 100 or 1000 times in a row to get a lot ...
2
votes
1answer
53 views

Open, Evaluate and Close notebooks sequentially

I wanna Open, Evaluate and Close notebooks sequentially. Code from question here ...
1
vote
0answers
48 views

Wrapping an association with a specialization of the buildin `Set` (=) function?

I want to wrap some association data into a dedicated symbol (S by example) ...
2
votes
2answers
83 views

How to make a contextual variable?

I have a question that would be trivial in OOP, but I am a newbie to programming in Mathematica, so I'm wondering how to deal with it. Basically, I want to create a package which basically involves a ...
2
votes
1answer
77 views

How to decorate data in a matrix for reporting purposes?

I want to create a report from two matrices m1 and m2 (already created, and available) with data. The report should (roughly) look like the output of the following code: ...
1
vote
2answers
47 views

I need the product of two functions be understood as a function itself (a Dirac delta example):

Define: In:= Dirac /: Dirac[x_, y_] f_[x_] := f[y] This works like Dirac's Delta. For example, In:= h[x] Dirac[x,y] Out:= h[y] perfect! However if I ask: In:= h[x] k[x] Dirac[x,y] Out:= h[y] ...
6
votes
6answers
306 views

Certain search in list

A list $LL$ of $n$ real numbers is given. For each element $e$ of $LL$ to find the position of the closest to the right element of $LL$ which is at least twice bigger than $e$ and return it. If ...
2
votes
1answer
35 views

Hierarchically adding {…keys..}->value to an association

Given a list of keys {"a","b","c"} and a value 3 (associated to the last key) I want to define a function that is equivalent to ...
2
votes
1answer
49 views

Define a function with specific permutation properties

I want to define a function evaluate[f_[x__]] which acts on an arbitrary function f[a,b,c,d]. The function ...
2
votes
1answer
59 views

Find critical radius in percolation

I would like to examine the percolation from the left edge to the right edge on random lattice. Suppose I have a rectangle with N random points on it. ...
1
vote
4answers
90 views

How to put solutions of mutiple DEs with NDSolve in table

I have $N$ differential equation for each $s \in {1,2,...,N}$ on the domain $x \in [1,2]$ of the form (e.g.) $xf_s'(x) + \log(xs) f_s(x)+1 = 0$, with the boundary condition $f_s(1) = e^{-s}$ Now I ...
5
votes
1answer
87 views

Mapping a function f[xi_,xj_] over a list {x1, …, xn} with the i < j restriction

I am often facing the situation where I have a list $\{...x_k...\}$ and where I want to compute: $$ \{...f[x_i,x_j]...\}\text{ with }\ i<j $$ Unfortunately, I have not been able to find an ...
0
votes
0answers
57 views

Import and merge PDF files

I have a folder with several pdf no more than 50, I would like to import them to be disordered and that the output was a single pdf (you can imagine it as a proof of form A and we want to produce form ...
2
votes
3answers
210 views

Find the 3D region containing the origin bounded by given planes

I'm writing a code to generate the Wigner-Seitz cell of the reciprocal lattice for a given set of lattice translation vectors. For example, consider the Body Centered Cubic (BCC) lattice whose basis ...
0
votes
1answer
36 views

Wrapped Association into a “structure”: how to define Equal[] and what are the good practices for package dev?

Using a nice answer https://mathematica.stackexchange.com/a/197936/42847 I got from a previous question I define: ...
3
votes
3answers
90 views

Efficient manipulation of Associations passed to functions, how-to? [duplicate]

I have some data wrapped into a MyData[data_Association] "structure". My Association contains some big arrays and I do not want ...
1
vote
0answers
30 views

A newbie question about the use of the FourierSeries functions

Although I have had no previous experience with the Mathematica Fourier Series functions ( or package ), I am writing a tutorial on Fourier Analysis and Transformations in a Mathematica Notebook, ...
9
votes
2answers
222 views

Finding the path in a graph from A to B then back to A with a minimum of shared edges

the problem is to find cycle from A to B back to A, so that the path B-A would use minimum edges from path A-B. The graph is undirected and can have cycles. The paths don't have to be shortest, they ...
0
votes
0answers
31 views

How to use the Mathematica [duplicate]

I am a new learner for Mathematica. I know just some basics of Mathematica, I can plot simple graphs. But, sometimes I have to plot some complicated graphs. Then, I am unable to plot that particular ...
12
votes
1answer
465 views

Pascal records and Mathematica programming

Background: "experienced" Pascal-programmer (DOS-era, never got into OOP) proud owner of Mathematica ver 11.2 have used Mathematica for years to do my share of number crunching and plotting to ...
0
votes
0answers
19 views

CDF and ElasticSearch [duplicate]

I have an large amount of data, in the terabyte range, in an ElasticSearch instance. The data is on an network air gapped from my Mathematica instance and I'd like to have an app to examine the data ...
0
votes
1answer
78 views

How can I use Compile to implement recurrence?

I am trying to make the code for the following recurrence. Here wjoin[[i]] is used for calling values from a data set and a is a ...
12
votes
2answers
287 views

Plot of histogram similar to output from @risk

In order to analyze simulated data, @risk provides a histogram with handle bars, so that we can move these handles to see what proportion of data are on each side. For example, . I am trying to ...
0
votes
0answers
28 views

Custom PopupMenu displays menu items as values instead of labels

I'm trying to create custom appearance for PopupMenu with the below code. The problem I have is with the menu items which are displayed as values instead of labels. ...
0
votes
0answers
28 views

Why is an integration error appearing during this code?

I'm really confused about this to be honest. If i evaluate approx[x,k] for some k, and then input the list into the Plot function, I get a plot. But if I try to use approx[x,k] directly, I get an ...
2
votes
0answers
42 views

Problem with PopupMenu: Its values don't update dynamically

I have a problem with PopupMenu inside DynamicModule, its values don't update dynamically as they supposed to. The example below ...
3
votes
1answer
58 views

How to get Mathematica to loop two functions at once

So I know how to get half of this problem. I am trying to run a loop that combines the following two function at once so I can see from my index i if any number satisfies both conditions. TO get the ...
1
vote
2answers
135 views

MapThread conflicting with DynamicModule

Cross-posted: https://community.wolfram.com/groups/-/m/t/1625808 Answer posted on Wolfram Community I'm creating an interactive UI which allows the user to import data from a spreadsheet, perform ...