# All Questions

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### 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 ...
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. ...
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. ...
116 views

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### 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, ...
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} ...
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 ...
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, ...
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 ...
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 $n=5$?
117 views

### Build nested function

By running the following code: ...
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 ...
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 ...
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 <...
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 ...
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 ...
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; ...
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### 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. ...
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: ...
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 ...
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### 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 ...
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 ...
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 $n$ ...
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 ...
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 ...
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 ...
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 ...
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 ...
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### 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 ...
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 ...
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### 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, ...
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### \$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 ...
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### 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 ...
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### 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 ...
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 ...
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. ...
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 ...
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) ...