2
votes
1answer
105 views

Symbolic multiplicative partitions

Let $p_n\#\equiv\prod_{k=1}^{n}p_k$ (primorial): p[n_] := Times @@ Prime[Range[n]] then the multiplicative partitions of $p_{1,2,3,4}\#$ are $$ \{\{2\}\},$$$$ ...
0
votes
1answer
148 views

Plot a real part of complex equation depending on a parameter

I would ask you to kindly provide me a way to solve this problem in mathematica way. Let the equation $z^2 + 9 -1.5 e^{- t z}=0$ where $z\in \mathbb C$ and $t\in \mathbb R^+$. In order to plot graph ...
0
votes
2answers
64 views

Define functions from two lists

I have two lists {G[x_,y_],F[x_,y_],C[x_,y_]} and {x*y-x, 3x+y, x^y} Now I need to define 3 functions ...
4
votes
1answer
692 views

Point style in ListPointPlot3D

In ListPointPlot3D, it seems the only point style available is the default, because there is no PlotMarkers option for this ...
1
vote
1answer
79 views

Typesetting help

I have a rather simple question that has me flummoxed. Let's say I have two matrices: m1 = {{a1, a2}, {b1, b2}}; m2 = {{u1, v1}, {u2, v2}}; I am looking to ...
1
vote
0answers
104 views

Is it the right output for Fourier?

I am learning Fourier Series at university so I wanted to do something with Mathematica to calculate frequency spectrum and harmonics of whatever function I create. This is what I have until now after ...
0
votes
2answers
230 views

Numeric mixed derivatives

In short I need NumericCalculus`ND extended to mixed partial derivatives. This can be done by nesting them, but care has to be taken to evaluate underling ND only when the parameters become numeric. ...
1
vote
1answer
145 views

Matrix and random, weighted assignment of rows

I asked a question in this category previously but my problem has changed. On one hand, I have a large number of data files as .dat format, and on the other hand, I have a matrix ...
0
votes
2answers
335 views

How to change the font of a color bar?

When using DensityPlot or similar, I want to change the font size of both frame labels and the color bar legend, but I can only get the frame labels to work. ...
2
votes
1answer
69 views

Can tab just mean “insert tab character”?

Is there a way to set the tab key to simply insert the tab character in a notebook? I often find the sometimes mysterious "features" bound to that key detrimental.
14
votes
2answers
686 views

Animating transition between all graph representations obtained from curated data

Pappus graph is one of many graphs whose various data is contained within Mathematica. Mathematica typically keeps several ways of representing such graphs: ...
0
votes
1answer
614 views

How to convert sine wave into square wave? (analog to digital signal)

I've got this plot with two sine waves and what I need is follow: Amplitude values can diverge from time to time like here min 100 and max 700 but another time it's 300 600. I guess I will not be ...
5
votes
1answer
162 views

When to use indexed variables

Still learning the fundamentals of the language I would like to ask you what advantages there might be in writing something like: a[1] = 2; a[2] = 4; a[3] = "x"; ...
3
votes
2answers
257 views

Multiplicative partition function

I am trying to create a multiplicative partition function that would generate something like ...
1
vote
1answer
69 views

Save selection as PDF - non-image format

I am trying to save the following plot as a pdf, so that I can import it into LaTeX: ...
0
votes
1answer
86 views

Defining the function of list of parameters

I'm defining the functions in the following way ...
1
vote
0answers
67 views

Export command in Mathematica trial version

Mathematica trial version does not support Export[] command. Is there a command equivalent to Export[] in order to export, say, ...
8
votes
1answer
549 views

Graphics3D from Mathematica to SolidWorks (for 3D-printing)

I have an 3D Graphic generated with Mathematica's Graphics3D, and want to use it later in SolidWorks. SolidWorks files are usually *.stp, *.step, *.stl extentions. google search hasn't given me a ...
6
votes
1answer
147 views

Can I read Chinese characters with ReadList correctly?

Just try this example: Export["a.txt", "这乱码问题该怎么解决呢\n***\n怎么解决嘛"] ReadList["a.txt", Record] ...
0
votes
0answers
34 views

Unexpected results from Thread [duplicate]

I've run into an issue where threading two lists with a generic function, f: Thread[f[{{1,1}, {2, 2}, {3, 3}}, {4, 5, 6}]] ...
2
votes
2answers
185 views

Generating $n$ random samples every time

Is it possible to generate $n$ random samples, and always ensure that $n$ samples are generated? eg For $n=5$: ...
18
votes
1answer
1k views

Faster way to compute the distance from a point to a surface in 3D

I am trying to compute the shortest distance between a point and a triangle in 3D ...
2
votes
2answers
156 views

Bug in ListVectorPlot?

Trying to evaluate the following expression kills my kernel (Mathematica 8.0.0.0): ...
2
votes
1answer
403 views

NDSolve::ndsz problem

I'm using NDSolve to solve a set of coupled differential equation which depend on a variable x. I noticed that when I set the range of x from a small value to a large value, I obtain solutions. But ...
2
votes
3answers
247 views

When exporting text, how can I set the line separator?

I want to export a string for a bash script. The terminal is naturally very picky when it comes down to the "\n\r" vs "\n", Windows vs. Linux, new line issue. How can I teach Mathematica to use "\n" ...
0
votes
3answers
88 views

Place symbols from small to big

I am wondering how to compare the different values of ω I derived in this code, and place them in order as follows. (use Print ...
1
vote
4answers
327 views

random split a dataset

I've got a very simple problem, but not so trivial. I need to split a dataset (input and output data) in three part randomly: training set 70%, validation set 20% and is test set 10%. First of all ...
0
votes
1answer
108 views

RegionPlot not working as expected

I was trying to evaluate the following expression: RegionPlot[a > 0 && 2 a + b == 0, {a, -2, 2}, {b, -1.5, 1}, PlotLegends -> "Expressions"] ...
2
votes
0answers
154 views

Computing a sum

I'm trying to make Mathematica compute this sum: Sum[(-1)^k (n - k)^2 Binomial[2 n, k], {k, 0, n}] As is, I get an awful formula: ...
9
votes
3answers
458 views

Showing the empty space in a Graphics3D plot

I would like to be able to visualize the empty space in a Graphics3D plot. For example, if I plot hexagonally close packed spheres using something like: ...
0
votes
0answers
122 views

Plotting Phase Space [duplicate]

I have these two Equ' $$x'[t]=Sin[y]$$ $$y'[t]=Cos[x]$$ and im trying to plot the phase space(plane) for this system... ive tryed Equationtrekker but cant seem to find the way to use it this way... ...
0
votes
2answers
149 views

Edit Automatic PlotRange

if I have a plot let us say Plot[x^2 - 5 x - 10, {x, 0, 8}] I want o check if there is a way to know the automatic plot range and to add or subtract from that ...
3
votes
1answer
193 views

Strange behavior of Reduce with a cubic equation

This equation: $(\frac{-a}{x})^2=\sqrt{\frac{1}{x}}$ at $a > 0$ and $x > 0$ has a clear solution $x=a^{4/3}$, doesn't it? However, ...
2
votes
1answer
53 views

Quoting definition explicitly

I'm trying to quote a definition using DownValues, OwnValues, etc. Everything seems to be fine, except for temporary symbols' ...
0
votes
1answer
199 views

Center Manifolds

...
7
votes
2answers
197 views

How to correct this, `f[a_] := FindRoot[eq == 0, {x, 0.5}]`, where `eq` contains a parameter $a$, without using `eq[a]`?

I want to solve an equation with a parameter $a$, and define the result as a function of $a$. It is something like this: ...
2
votes
1answer
593 views

Reversing Autocorrect, aka how to find the word that was supposed to be there

When I receive messages from people using their smartphones I usually see typos and, worst, typos corrected by Autocorrect. Now, I receive messages in English, which is not my first language. I can ...
5
votes
2answers
151 views

FullSimplify inconsistent

I'm having problems using FullSimplify to simplify a differential equation. The expression is simplifying just as I would like when I express a variable ...
2
votes
2answers
348 views

Plotting a Spericon and Bipyramid with 100 faces

I would like to plot convex polyhedron with 100 faces, which could be used as a die. My first attempt was asking for Conway's Hecatohedron. Unfortunatly, it can not be used as a die. Now there are ...
3
votes
2answers
139 views

how can I make a control for my vector equation in my simulation?

I'm trying to build a control selector or menu for equations to put into my curvature simulations. However all the code I've tried hasn't worked.Does anyone know how I could make a control selector or ...
2
votes
2answers
173 views

Why does GraphicsGrid rescale 3d plots?

In the documentation for GraphicsGrid, it says By default, GraphicsGrid will display graphics at their specified sizes So why does it rescale the 3d plots ...
1
vote
1answer
68 views

DownValues Type Access and Timing

I definitely use so much DownValues structure for some many applications like to replace some common structures in a some way. It seems that DownValues is so fast for access, and set. My question is ...
1
vote
1answer
50 views

Correctly substituting a matrix into a scalar equation [duplicate]

I am having trouble correctly substituting a matrix into an (originally) scalar equation. For example: A = {{3, 1}, {1, 2}} cp = CharacteristicPolynomial[A, x] ...
2
votes
1answer
215 views

Plotting John Conway's Hecatohedron

John Conway has given an explanation how a regular Hecatohedron (polyhedron with 100 faces) looks like: http://www.ics.uci.edu/~eppstein/junkyard/hecatohedron.html Conway explains: Here's a ...
0
votes
0answers
40 views

How to generate Koch curve in mathematica [duplicate]

How is done in Mathematica to generate the curve? Exists in the fractal geometry Koch curve, consisting of partitioning a line segment of lngitud 1 in three equal parts, by removing the central part ...
21
votes
2answers
617 views

High-quality RegionPlot3D for logical combinations of predicates

Unlike RegionPlot, RegionPlot3D copes poorly with logical combinations of predicates (...
0
votes
0answers
124 views

Viewpoint options for a 3D plot [duplicate]

Let's say I created a 3D plot in Mathematica. It's not oriented the way I want it, so I manually rotate it (in the output cell) to a desired view. (I tried playing with some view options in the code, ...
1
vote
1answer
86 views

Simplification of linear algebra [duplicate]

I have a few vectors defined as V1 = Array[v1,3] V2 = Array[v2,3] V3 = Array[v3,3] And I am trying to solve a very simple equation along the lines of ...
1
vote
1answer
210 views

Show that three given vectors lie on a line, a plane, or span 3-space

Given three vectors, {2, 0, 0}, {0, 2, 2}, {2, 2, 3}, how could I see if they are all on the ...
0
votes
1answer
101 views

N-level exponential moving average

If anyone knows how to write a mathematica code for n-level exponential moving average or someone has written already the code ?

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