2
votes
2answers
50 views

Import a column of data, make a matrix from it and export it WITHOUT curly braces

I'm new here and with Mathematica, too. I want Mathematica to import data from a txt file (it has one column of data). These entries are z-values. From this I want to make a matrix - 508 entries make ...
4
votes
1answer
31 views

Relative factorisation with scalar quantities

I'd like to find a natural way to tell mathematica that a given unknown in a polynomial should be treated as a number, unlike the other variables. Typically I'd like to sum two polynomials in several ...
3
votes
3answers
71 views

List connectivity of points in discretized mesh

I'm trying to automate the extraction of the points and a compatible connectivity list for meshes created using the DiscretizeRegion or similar method. If I create ...
2
votes
0answers
19 views

How to obtain the value of a single symbol with mathlink

I am trying to write a (C) routine which reads the value (a list) assigned to a single symbol in mathlink. I tried things like ...
0
votes
1answer
109 views

How may I avoid ParametricPlot3D clipping? [duplicate]

What I am doing: ParametricPlot3D[{Cos[z/2]^6 * Cos[t],Cos[z/2]^6 * Sin[t], z}, {t,-Pi, Pi},{z,-Pi,Pi}] What I get: What I want: what I get, but without the ...
2
votes
1answer
96 views

Solve an inequality involving a sum with a parameter

Good day. I am new to Mathematica and I am looking for advice. Is it possible to solve $$\sum_{k=0}^{n} \frac{p^k}{k!}>0$$ for $n$ where $p$ is a parameter? When I do ...
3
votes
2answers
141 views

Generating Meshes with Conforming Boundaries for FEM

I would like to solve a PDE on an annulus with some boundary condition that relates the inner circle to the outer circle. (For example, periodicity along radial lines). If I use a finite element ...
-3
votes
0answers
34 views

Hold and Release an import [on hold]

I'm in Manipulate bloc to make a dynamic car selector, but there is a point in which i need to load the car specifications but if I don't hold the import causes an error here is the code ...
0
votes
0answers
46 views

How to deal with Missing[NotFound] [on hold]

I'm getting the position in array of pick value, and always obtain Missing[NotFound] until I select something, there are any way to check if variable is a number ...
5
votes
1answer
44 views

Export XMLElements with MathML contents

Setup Here's my mathML expression: mathML = ExportString[1/2, "MathML"] ...
2
votes
2answers
79 views

NDSolve : Boundary conditions of lower order

Given the (dummy) problem ...
0
votes
0answers
11 views

Physical interpretation of residues [migrated]

What is physical interpretation of residues of poles (of any order) of a complex function? Poles represents the points where a complex function cease to be analytic and residues are calculated to ...
1
vote
0answers
47 views

Use Solve[] with Bessel, gamma, and hypergeometric functions?

I need to find values of {a,b,c} such that the 0th, 2nd, and 4th order moments of f[x]=Exp[-ax^4 - bx^2 - c] will equal respectively {1,2,10}. I didn't really expect this to work, and it didn't: ...
-5
votes
1answer
59 views

how to change parameters in NDSolve? [on hold]

I want to solve a PDE with parameters chosen based on the sign of derivative. For instance in the following PDE ...
12
votes
0answers
106 views

A question about weighted graphs

Bug introduced in 8.0 or earlier and persisting through 10.2 or later I need create a weighted graph with given data. Number of nodes: $53$ $\quad$ Number of edges: $91$ ...
0
votes
1answer
81 views

Huge EPS file when exporting Graphics3D [duplicate]

I am using Graphics3D and Sphere to generate a figure. But unfortunately, when I save it as an EPS file, its size comes to ...
0
votes
1answer
39 views

Applying transformations to data coming from an STL file

I am very new with the use of 3D graphics in Mathematica, so my question might be very naive. I need to Import an STL file, apply transformations to it (rotation and translation), and export it back ...
3
votes
2answers
204 views

Storing Variables in “Loops” and Point Plotting

Given the function $y=\sin x$ defined over the region $-\pi \leq x \leq \pi$, I need to implement a "do loop" such that I sweep over 100 or so points $-1 \leq y \leq 1$ and find precisely the two $x$ ...
0
votes
1answer
35 views

The FindRoot output only with numbers [duplicate]

I have this code in Mathematica: FindRoot[{Sin[x - y + 2] - x == 0, Sin[2 x - z] - 8 z == 0, Sin[z + y + z] - 2 x == 0}, {{x, 0}, {y, 0}, {z, 0}}] where it's ...
0
votes
0answers
28 views

How do I make a RNG in a function run only when I call the function? [on hold]

In Mathematica, I've made the following function: ...
1
vote
1answer
53 views

Defining a derivative on a custom function

I am trying to define a derivative that acts on a custom function, $f$, such that when it acts, it increments one of the arguments of by 1. f is not defined; I just want to use it to keep track of ...
3
votes
3answers
131 views

Find position avoiding For loop

I have a list: {a,b,c,d,e,f} And a function sizeFunc[element_] which returns the size ...
9
votes
0answers
70 views

How does Dataset compare to DataFrame in pandas?

Pandas is a Python package providing fast, flexible, and expressive data structures designed to make working with “relational” or “labeled” data. Just like ...
1
vote
1answer
33 views

NumberLinePlot: How to make the 3rd list (c) appears with “black crosses” or “void circles”?

a = {1, 2, 5, 2} b = {2} c = {1.75, 2.88, 3.25} NumberLinePlot[{a, b, c}, PlotStyle -> Directive[PointSize[0.032]]] I thought about PlotMarkers or PlotStyle, ...
1
vote
2answers
91 views

Plotting a function with implicitly defined variable

I have a question about plotting a function with an implicitly defined variable. I think the solution should be something similar like here: Define a function with variables linked implicitly but I ...
1
vote
1answer
48 views

Plotting function in cylindrical coordinates (r,theta,z) [duplicate]

I have a function of two variables (r,theta), and I would like to plot it as a surface using cylindrical coordinates. Based on my research, there is no built mathematica function for plotting ...
0
votes
0answers
6 views

Can these steps be converted to a mathematical expression using equations/graph theory/Calculus/Set theory/functions/? [migrated]

Want to convert below algorithm into a mathematical model:- General points 1. Let there be a Connected Directed Graph. G = (V, E) V vertices or nodes E edges. This graph can be seen as a network ...
2
votes
1answer
43 views

Dropping rational coefficients

I have a list of expressions (they all are exact numeric quantities, not containing any variables), some of them have integer or rationals coefficients, or complex coefficients with rational or ...
2
votes
2answers
66 views

Trouble simplifying using Replace

I have the following expression: w.a.b.r+w.c.d.r I want to get: w.(a.b+c.d).r So far I used ReplaceRepeated: ...
0
votes
1answer
62 views

Sum with 2 different variables

I want to plot Contour or Streamplot a function with a sum. The first part (Abs[v/u]>1) looks like this: $L(u,v)=\sum_{s=0}^\infty \frac{(-1)^s}{2s+1} ...
3
votes
2answers
76 views

Gauss Fit to List of 2D Points

I've been trying to find a solution to what I think is a common problem. I have a list of Data like ...
1
vote
1answer
36 views

How to select components selected via SelectComponents?

I have selected the components of a "reduced" (dilated, thinned) image, now I need to go back to the original image and find the coordinates of the components I have found. My code currently does ...
1
vote
0answers
28 views

Accessing the elements of a list of values [on hold]

I have a list of polynomials (all with the variable x) called lyle and a function that accesses this list and evaluates it at ...
3
votes
1answer
187 views

Decode a text which is encoded with UTF-8

I would like to decode a text which is encode with UTF-8. My code is here : ...
4
votes
3answers
273 views

Implementing Picard's Iteration for solving ODEs

Picard's Iteration is a way of solving the IVP $$y'(x)=f(x,y(x)), \quad y(x_0)=y_0 $$ It consists of defining the following sequence of functions recursively: $$y_0(x):=y_0 \\ ...
4
votes
2answers
506 views

Order of a pole

Is there a simple way to determine the order of the poles of a rational function? I have a difficult function where I need Mathematica to find the poles. It would be interesting to also know what the ...
3
votes
0answers
35 views

Setting MaxIterations for neural network function `Predict`?

The neural network implementation of Predict seems to support a number of undocumented options as shown in a previous question: How to change NeuralNetwork ...
1
vote
1answer
37 views

Use e notation in Stream output [on hold]

I'm trying to save the results of a huge Radia calculation. I evaluate the function in a loop at multiple locations. To export the data my first approach was to fill a Table and use the ...
0
votes
0answers
51 views

The graph of a piecewise function [closed]

Let $$f(x)=\begin{cases} n,\quad\text{if }\quad n<x<n+\frac{1}{n^3}, \\ 0,\quad\text{if }\quad n+\frac{1}{n^3}\leq x\leq n+1 , \end{cases}$$ Using mathematica, I attempted to draw the graph ...
0
votes
1answer
83 views

How to make the plot smooth

There are some stranges point which cause the figure isn't smooth. I think that the reason is the method of numericial integration. Here is my code, it's pleasure that one can revise the drawbacks in ...
1
vote
0answers
32 views

How to avoid import evaluation until if wil return true

My goal is to import a data from url that depends of 1 parameter, this initialy value is null or undifined en yo have to selec some popup and then the variable has value, what is the method to do ...
1
vote
1answer
45 views

Pure “Select” function over matrix

I have several lists of tuples in the following shape: l1 = {{1, 134}, {2, 314}, {3, 164}} I do want to select, from each list, list elements fulfilling a ...
0
votes
0answers
3 views

Max/Min to logical operator trasformation and viceversa [migrated]

I have some doubts in trasforming conditions that involves max/min in logical operator condition and viceversa. In particular, should be (I put some examples, I would know if I'm right and the ...
0
votes
1answer
31 views

Finding solution of equation with differentials [closed]

I am trying to find the point of maximum exponential curvature, where the exponent equation is: y = 0.2e^(0.4x) I know the equation for this point is: k = y'' / [(1+y')²]^(3/2) How can I code this ...
0
votes
0answers
60 views

PDE: Inconsistent equation dimensions

EDIT: I need to solve the following PDE: $\nabla^2\vec{A}=-\mu_{0}\vec{j}$ where $\vec{j}=\sigma\vec{E}$ and $\sigma=1*10^{10}$ which basically boils down to three different PDE's; ...
1
vote
1answer
47 views

How to apply Simplify only to elements of list that cause specific Warning

I have a set of replacement rules I use to analytically compute nested integrals of very long symbolic expressions since Integrate literally takes forever. To do ...
1
vote
1answer
67 views

Pulling out a prefactor from a dot product

I have three complicated vectors u, v and w as well as three simple prefactors ...
0
votes
0answers
23 views

General formula for total derivative [closed]

I have a real-valued function $f\{x, y(x)\}$, with $x,y\in\mathbb R$. I would like to compute the total derivative with respect to $x$ in Mathematica. However, I am not able to write exactly that ...
0
votes
3answers
42 views

Generating a large table of values and selecting some of them following some condition

I am working on a problem where I have to generate a table of components while each component of the table has 18 entries. Six of the indices among 18 run from 0 to 1 while the other 12 can take ...

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