0
votes
0answers
3 views

Partitioning a set with a condition and ability to change it?

I asked this question and there is nice answers but only the first answer permit us to change the condition to another if we want, but this answer use a brute force approach and we can't use a ...
0
votes
2answers
20 views

Create matrix using loop?

Here I have a list of numbers (900 numerical values) denoted as d1-1, d1-2, d1-3.....d1-30, d2-1, d2-2, d2-3........d30-30. I want to create a matrix (900x900) which is organized as the below picture. ...
1
vote
0answers
17 views

Is MatrixExp[m,v] always faster than MatrixExp[m].v?

For non sparse matrix m, is MatrixExp[m,v] supposed to be faster than MatrixExp[m].v? This seems to be true only if m is purely real or imaginary. ...
2
votes
3answers
116 views

Numerical voodoo in mathematica?

So, I was doing some calculations in Mathematica, and came across the following paradox! (I may be exaggerating, but...) I wanted to solve the following equation: $3.33333*10^{-15} - 3.33333*10^{-15} ...
0
votes
0answers
12 views

Having a 2D Parametric Function Wrap Around a Geometric Region

I am trying to study curves on the flat torus (the unit square where opposite edges are identified with each other) and I was wondering if there is a simple way for me to take a parametric curve that ...
1
vote
2answers
33 views

How to combine scaled, rotated, etc. graphics objects?

This may be a trivial question, but I seem to be missing something. Let's say I create a graphics object like so: ...
4
votes
1answer
53 views

smooth spline through airfoil coordinates

I am trying to produce a smooth spline curve through a set of airfoil coordinates. An example for the data I am trying to use is here, and I am reading the file like so to get rid of some extraneous ...
0
votes
0answers
22 views

Pulling out an exponential function from the a general equation

How can I pull out an equation from the general equation of motion of a system in Mathematica ? Actually, I am trying to solve the equation of motion of a spherical shell, therefore, I am trying to ...
1
vote
0answers
35 views

ListPlot Problem -Graphics- returned

I am running Wolfram on a Pi-Top (Raspberry Pi 3). The command ListPlot[{10,9,8,7,3,2,1}] returns -Graphics- and no plot. What am I doing wrong?
-1
votes
0answers
27 views

How to solve an equation with previously set variables

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
18 views

Compiling a function while dealing with symmetries

I have the following function that I would like to compile: ...
0
votes
2answers
28 views

Make a grid of lines with a For[] loop inside a manipulate statement

can anyone help me? I'm tring to write a Manipulate[] statement that can be able to modify a grid of lines in length, height and change the space between them. It ...
2
votes
1answer
26 views

Edit piecewise function

Downstream of a long process I got the following function: $\begin{cases} 0 & x < 0 \, \vee \, x > \frac{307}{400} \\ 14.27-7.44\,x & 0 < x < \frac{307}{400} \\ \text{...
0
votes
0answers
19 views

How to extract the certain variable from output of coding

Good day, Can anyone help me how can I extract the certain value from the output after run the coding. The output of the coding, ...
1
vote
1answer
33 views

How to highlight listplot data

I plotted a data ListPlot[{{1,2,3},{4,5,6}}]. When I point the mouse over point {1}, it should appear at the end of the tooltip and the corresponding data point {4} ...
0
votes
0answers
30 views

Can open mathematica in terminal, but kernal can't

When I write mathematica in Terminal it works and I can use mathematica , but when I write math < test.txt It gives bash: math: command not found. where test.txt contains mathematica code. Can ...
4
votes
0answers
34 views

Make NSolve faster by keeping only one solution

Dear Mathematica users, NSolve usually returns all numerical solution it can find. When a variable is squared in some equation, ...
2
votes
0answers
35 views

Derivation of an interpolation function with multiple arguments

I have the following interpolation function: f[x_,a_,b_]:=70 s[a,b][[1,1,2]][x] where s[a,b] is the solution of a ...
3
votes
1answer
48 views

Showing a polygon in Mathematica

Could anyone be able to construct two shapes, a $n$-gon $P$ and a regular $n$-gon $Q$, say $n=5$?
2
votes
2answers
117 views

Build nested function

By running the following code: ...
0
votes
1answer
41 views

Trying to get the values of sliders from a module

I generated n number of Sliders using the idea from Manipulate with a variable number of sliders But I need the updated values of these sliders to use to evaluate ...
0
votes
0answers
66 views

Robust FindRoot search

I have the following simulation that models a rocket landing (flat Earth, no atmosphere, constant gravitational acceleration), which uses root finding to figure out when to start and stop the engines ...
11
votes
1answer
66 views

Working with DynamicModule: SetDelayed + OwnValues

Shortly, definitions in form of e.g. x:= RandomReal[] have to be avoided inside DynamicModule[{x}, ...]. Minimal example, this <...
0
votes
1answer
42 views

Infinite Sum - Result not correct for all cases?

Evaluating the Sum Sum[a^i, {i, ∞}] yields -(a/(-1 + a)) which obviously only holds ...
0
votes
1answer
31 views

CountryData function

I under that Mathematica are able to extract data from a cloud/ online sources. Pardon the improper use of jargon for programming and IT is not my area of familiarity. Are the data that Mathematica ...
0
votes
1answer
32 views

How can I plot the graph based on time from TimeUsed?

Good day everyone, Can anyone help me how to plot the result using time from computer. Here, I used timeUSed to generate the time; ...
0
votes
1answer
63 views
0
votes
2answers
60 views

Large matrix: Finding eigenvalues and ordering it with respec to the highest coefficient of its eigenvectors

I have a 900x900 matrix to diagonalize. After diagonalizing it, I have a table of eigenvalues and eigenvectors. For convenience, I start with 3x3 matrix. ...
0
votes
0answers
52 views

Make integration/ plot run faster? (takes hours)

I am using Mathematica 10.0.2.0. Here is the code I am working with: ...
1
vote
0answers
26 views

Filling between two plots up to some boundaries only [duplicate]

Suppose I have plotted two functions $f(x)$ and $g(x)$ on the same plot. I would like to shade the area between the two curves only when $f(x) \geq g(x)$, but I cannot get the Filling command to do ...
15
votes
0answers
78 views

What has changed in pattern matching functions with the Orderless attribute?

In making an attempt to answer this question, we ran into a version-dependent pattern-matching issue. An extended discussion in the comments transpired, and some inconsistencies arose. Consider the ...
0
votes
0answers
46 views

Mathematica, stop sorting my output! [on hold]

I'm trying to get some output from Mathematica / WolframAlpha, but it's coming out in a useless format. Mathematica is, for some reason, sorting my output. Below is the output from my function and ...
0
votes
1answer
34 views

Max iterations for NestWhileList [on hold]

I'm writing Turing machines with a halting state. Many of these tms will never reach the halt state and I want a way to tweak NestWhileList so it runs a max of $n$ ...
0
votes
0answers
18 views

Wolfram Development Platform won't show my files

I just logged into Wolfram Cloud, so far I had no problems using it. But now, with this error when I try to open the home directory: What could be the problem? I don't have access to any of my ...
4
votes
0answers
55 views

Does Mathematica have built-in support for multivariate regression?

I know that LinearModelFit can generate a model of a single response variable as a function of a set in input variables. Does Mathematica provide support for ...
5
votes
1answer
53 views

Using Interval Slider in Manipulate for Plot Functionality

I am trying to incorporate Interval Sliders in Manipulate to allow the user to select a range to view a given plot. Here is an example that I have constructed for ...
13
votes
3answers
424 views

Converting a Sierpinski tetrahedron to a Graph

I need a representation of a 3D Sierpinski gasket in a form of a graph to perform some simulations on. The 2D version is included in GraphData[], but the 3D one is ...
0
votes
0answers
35 views

What is wrong with my formulas for a mathematical model of a double pendulum? [on hold]

I wanted to create a computer simulation on Matlab, using a model for a pendulum from this study (A double pendulum model of tennis strokes. Rod Cross. Uni of Sydney, 2006) - Link I wanted to use the ...
0
votes
0answers
16 views

Problem in plotting [on hold]

What is wrong with Plot3D[Sin[x y], {x, -2, 2}, {y, -2, 2}, PlotPoints -> 30, Mesh -> True, ]; It is almost the same as here (on page $15$) with the exception that I erased the last line ...
0
votes
0answers
26 views

Evaluating Elliptic Sine function

I am new to mathematica. I want to evaluate the elliptic sine function(se_r): http://mathworld.wolfram.com/EllipticSine.html The straightforward way of doing it would be using it's definition ...
2
votes
1answer
76 views

How to solve time dependent pde?

I have set out to try and solve a time dependent wave equation with specific boundary conditions, but I am running into a bit of a snag. As you can see, I am trying to solve for the wave function u[t, ...
1
vote
0answers
33 views

\$MinNumber vs. \$MinMachineNumber [on hold]

I'm working on some code that is giving me a division by 0 error, but I don't think I'm dividing by any functions that could come out to be 0. At one point it was suggested that this could be caused ...
0
votes
0answers
26 views

Filtering bad urls from a list of image urls [on hold]

I have about 90k image urls and I'd like to Select only the ones that are real images. Map[Check[Import[#], Nothing] &, urls] would take about 6 hours. Any ...
2
votes
1answer
25 views

How does AdjacencyLists work on SparseArray

I have been working with large SparseArray and have noticed the properties are very very useful and fast. I wanted to manipulate my large sparse array in ways similar to the properties. Looking at the ...
7
votes
1answer
78 views

How to efficiently implement k-FN (k-Furthest Neighbors)?

I'd like to pick k points from a set of points in n-dimensions that are approximately "maximally apart" (sum of pairwise distances is almost maxed). What is the simplest efficient way to do this? For ...
0
votes
1answer
33 views

Is it possible to get same answer from NonlinearModelFit with and without errors on data? - How to insert errors in NonlinearModelFit?

I want to use NonlinearModelFit with the following data. I tried it firstly without inserting any error bar. ...
0
votes
0answers
35 views

Create n number of sliders with push of a button

I am trying to create an app and a part of it I want to plot 2D slices of n dimensional data. For that purpose I ask the user which plane he/she wants to use and change the other dimensions with a ...
0
votes
0answers
19 views

Why isn't this minimize function returning the optimal answer? [on hold]

I am trying to minimize the following equation by solving for s1, s2, s3, s4 (where s1+s2+s3+s4=20, and they should be positive integers) ...
7
votes
3answers
89 views

Transformation rule for arbitrary number of argument expressions

I am failing to write a Mathematica transformation rule that replaces e.g. f[a + 3, b + 3, c + 3] with f[a, b, c] + 3 for an ...
0
votes
2answers
34 views

If/else conditional in Mathematica

I am a beginner in Mathematica. How can I turn the following Matlab commands into Mathematica commands. ...

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