Questions on correct (or improved) formulation of Mathematica code to achieve particular results. Use this tag (not "symbol") for questions about all those odd @@ /@ # & and ~ characters.

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-1
votes
0answers
34 views

How to solve an equation with previously set variables [on hold]

I am trying to set up an equation with multiple variables and use the Solve function to simplify it and plot the result. However, when I plug in my equation to the Solve function, it just gives me an ...
0
votes
0answers
35 views

Part command in a matrixform [duplicate]

I do have a MatrixForm a table which I would like to pick just a part of it. Is it possible to somehow command part[[]] for a <...
3
votes
1answer
93 views

Speedier Algorithm or Set of Steps to Increase Speed of Coefficient Generation

Good morning. I am working with higher powers of the Generalized Euler Number generating function $$\left[\frac{n}{\sum_{j=0}^{n-1}\exp{\left(w_n^jx\right)}}\right]^\alpha$$ where $w_n=\exp{\left(...
7
votes
4answers
181 views

How to avoid repetitive calculation when doing numerical integral?

Suppose I have a function f[x] which is very complicated, together with a function g[f[x]]+h[x] to integrate. That is: ...
1
vote
0answers
41 views

Simple list manipulation [closed]

I have two lists: {1,2,3} and {a,b,c} and I want this result: {{1,a},{2,b},{3,c}}. What is the right command? How does one call such an operation?
10
votes
1answer
212 views

Should I add a semicolon after a function definition? [duplicate]

should I write the program like this: f[x_]:=x^2; g[x_]:=x+2; or should I write the program like this: ...
4
votes
2answers
141 views

How to calculate this probability?

Here I want to find the probability $p$ which is given by $$p=\int_0^{r_d}\mathcal{L}_I(\beta r^{\alpha}|r)f_R(r)dr$$ with $r_d=1$ and $0 \le r\le r_d$. I want to calulate the probability for ...
4
votes
2answers
71 views

Grouping/precedence for “/@” operator

This returns errors: {#[[1]],#[[3]]} & /@ {#[[1]],#[[2]],#[[3]]} & /@ {{"A","B","C"},{1,2,3}} Part::partd: Part specification A[[1]] is longer than ...
3
votes
2answers
64 views

How to create assignments to OverVector programmatically

I wish to write a function that accepts two lists. The 1st argument is a list of lists, holding the components of a several vectors. Ex.: comp = {{a, b}, {c, d}}. ...
5
votes
2answers
143 views

Plotting an equation describing a Joukowski airfoil

I am trying to plot an equation that will give me a Joukowski airfoil and am having trouble getting any results. The equation that I am using is as follows: ...
0
votes
0answers
39 views

Question on Poincare section example

I'm trying to make a Poincare section. On the Wolfram Documentation Center they give an example that includes the lines ...
1
vote
1answer
82 views

integrating with multiple indicator functions depending on each other

I need to compute the following integral with three indicator functions, $I(x)$, $I_1(x_1)$ and $I_2(x_2)$, $$ \int_0^1\int_0^1I(x)\left( \ I_1(x_1)\,x_{1} + I_2(x_2)\,x_{2}-1 \right) dx_1 dx_2 $$ ...
21
votes
5answers
4k views

How do I increase the readability of this code?

Below is some code I am working on; being a beginner. How can I increase the readability of the part behind Manipulate? I can't read my own code anymore, because it is simply too long and unordered. ...
3
votes
1answer
135 views

How to get a best fit line on a scatterplot?

I know that I am supposed to call listplot inside of the show function but I can't seem to get that to work. The best I can get is this, which has the best fit line following the scatterplot. How do I ...
0
votes
0answers
66 views

Watched a Livestream with Christopher Wolfram, he used an operator that I can't find [duplicate]

I understand /., /@, /; and documentation exists in the normal way for all of those but I can find nothing on /*
0
votes
2answers
53 views

Problem with ParametricPlot with Im and Re [closed]

I have a problem, How can I plot theses functions from 0 to 2 Pi : Re(e^(iaϕ+(iϕ)^b)), Im(e^(icϕ+(iϕ)^d)) Re(e^((iϕ)^a) e^((iϕ)^b )), Im(e^(icϕ+(iϕ)^d)) Re(e^(iaϕ+(iϕ)^b)), Im(e^((iϕ)^c) e^((iϕ)^d)...
4
votes
3answers
248 views

How to set multiple parameters to zero?

Say I have the matrix A = {{a,b,c,d,e}, {f,g,h,j,k}} and I want to set some of these to zero. I have been doing this via ...
1
vote
2answers
146 views

Defining a variable with comma (or any other separator) in its name?

How can I define Mathematica variable/function with comma in it? For example, defineL00,1 as a variable? I plan to use L00,1 ...
0
votes
0answers
15 views

Problem with PolarPlot and Table [duplicate]

If I have a set of numbers, for example grid = N[Table[n^2/2, {n, 3, 24}]] And want to plot that as circles I can either use Graphics[] and Circle[], or ...
1
vote
1answer
64 views

Can't get a numerical value for this vector operation

I have written these codes: ...
1
vote
2answers
47 views

How can I specify the plot range of a BoxWhiskerChart? [closed]

I am combining multiple BoxWhiskerCharts using GraphicsGrid. This works properly, however I want the different charts to have ...
2
votes
1answer
39 views

A natural syntax for a Query that holds

Often I have an unevaluated expression in a RuleDelayed Key-Value pair and subsequently want ...
3
votes
2answers
157 views

Is it possible to assign numbers generated in an Error-Message?

If I have a differential equation of the form ...
0
votes
1answer
39 views

Replace argument of delayed function before it evaluates [duplicate]

How should I use replace so that f[x_] := x^2 Replace[f[3], 3 -> 1] OUT = 9 evaluates to 1, instead of 9? This way, the replacement of the argument is done ...
0
votes
1answer
76 views

Mapping over function's several parameters regions [closed]

About this post: Mapping multiple parameters of a function to specific values I wonder if the parameters a and b have ranges ...
1
vote
1answer
77 views

Generating sequence of averages of averages of partial sums

I have been given the following code that generates the sequence of averages (of the partial sums) of Grandi's series: ...
0
votes
0answers
57 views

Syntax for Neumann/Robin condition in NDSolve [duplicate]

I can't follow the logic of how a NeumannValue term is to be incorporated into a pde to provide a BC for NDSolve. The ...
0
votes
1answer
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) {...
3
votes
3answers
189 views

Replace For with If in Mathematica way

I have this code: ...
0
votes
1answer
72 views

Solving equations with change of variables is not working?

I want to express it in the form $$\text{expr=}\int_{-\infty}^{\infty}C_1\exp\left(-t^2\right)f(t)dt$$, i.e., the integrand is a bounded smooth function $f(t)$ times $\exp(-t^2)$ and the domain of ...
2
votes
1answer
128 views

Syntax f[x_][y_]

Need to understand the principle of the distinction between f[x_,y_] and f[x_][y_] It seems also that z[x_, y_][a_, b_, c_][α_, β_] := a (x + y)^b + c/(α-β) ...
0
votes
1answer
39 views

Is it the correct syntax with TransformedDistribution?

I define a function as f[x_] := ...;which is in fact the PDF of a random variable $X$. The PDF if given by $f_X(x)$. Let $Y$ is a random variable, which is the ...
0
votes
1answer
61 views

Why doesn't Mathematica solve this non linear (fractional) ODE? [closed]

a1 = NDSolve[{y1''[x] - 0.1 y1[x]^0.25 == 0, y1'[0] == 0, y1[1] == 1}, I get the following errors - Power::infy: "Infinite expression 1/0.^0.75 encountered ...
1
vote
1answer
64 views

List of Inequalities in RegionPlot with different colors [duplicate]

Starting from the example of the Documentation: RegionPlot[{x^2 < y^3 + 1, y^2 < x^3 + 1}, {x, -2, 5}, {y, -2, 5}] Which gives a nice plot with two ...
5
votes
0answers
140 views

Is there an internal logic behind short form symbols, such as @ (Prefix), @@ (Apply), /@ (Map), /. (ReplaceAll) [closed]

To me, function names (such as Apply and Map) seem more intuitive than their symbols (e.g. @@...
1
vote
2answers
65 views

MMA gives error when a different PDF expression is used for the same distribution

I have the following MMA code. Note that the function I declared at the very beginning is the PDF of square of a Nakagami Distributed random variable. With $m=1$ and $P=1$, $f(h)$ becomes Exponential ...
2
votes
2answers
59 views

Substituting within a function definition that includes Simplify

I would like to define a function like myfunc[f_] := Simplify[(f/g)] where g will be substituted/replaced with the current value of g at the time of definition. ...
2
votes
2answers
463 views

What is the meaning of “/.”? [closed]

I've looked to the built-in help of Mathematica, but I still can't understand the usage of /., like in the following expression: ...
0
votes
1answer
63 views

Partial derivative of function of two variables

This question is not enlightening nor is it difficult. But some part of my notation or how I have defined my functions is messing up the D[f,x] function. ...
1
vote
1answer
69 views

Mathematica Empty Plot FourierSinSeries function

I'm trying to get a plot of different order Fourier series of the function x-1, why does Mathematica give me an empty plot? ...
3
votes
2answers
47 views

Better alternative to Hold/ReleaseHold for postfix application of Monitor

Trying to Monitor a process using the postfix notation, as in Table[Pause[n/10], {n, 5}] // Monitor[#, n] & fails: the ...
9
votes
0answers
125 views

Is there a linter to help write good Mathematica code?

I don't do much real programming, but I've recently been turned on to Atom, which has linter plugins for over 50 languages to make coding easier (most drawing on pre-existing lint-like programs). In ...
0
votes
1answer
47 views

Applying multiple functions to a single column in a table

I've seen similar questions, but I'm having trouble applying solutions found there to my situation. My sorting function: ...
1
vote
0answers
47 views

Is it possible improve the code scanning beyond what SyntaxQ does? [closed]

Please, consider this package (* ::Package:: *) BeginPackage["HelloWorld`"]; a::usage="A"; b::usage="B"; Begin["`Private`"]; a=1; b= End[]; EndPackage[]; ...
3
votes
1answer
55 views

Undocumented “Output” alignment argument to “Column?”

In this SE question, Inheriting Stylesheets when using CreateDocument, I noticed the literal string argument "Output" to Column. ...
3
votes
3answers
157 views

How to get the long logic expression with a terse method

I have a long logic expression (x==2||x==3||x==4)&&(y==2||y==3||y==4)&&(z==2||z==3||z==4)&&(m==2||m==3||m==4) How to get it by a terse ...
3
votes
1answer
61 views

How to set similar constraints on multiple variables in Solve

In this equation: var = {x, y, z, m}; Solve[x + 2y + z + m == 14 && And @@ Thread[2 <= var <= 3], var, Integers] {{x->2,y->3,z->3,m->3},{x->3,y->...
1
vote
1answer
63 views

How to assign options to a variable?

I want to redefine a function similar to Plot like this: ...
0
votes
0answers
38 views

Syntax question for declaring variables [duplicate]

I have a very basic syntax question for declaring $X_{hb}$ a variable. f[Subscript[X, hb_]] := Subscript[X, hb] In mathematica instead of writing the ...
3
votes
3answers
173 views

how to convert a bundle of if statements into a simple one.

hi i am just trying to create a matrix depending on some specific conditions for which i designed these codes which work fine but i want to concise these codes. ...