# All Questions

480 views

### Wolfram Workbench 2.0 on Xubuntu 14.04 LTS trusty

I'm trying to install Wolfram Workbench on Xubuntu 14.04 but the apptication doesn't start. Knowing that WWb is a 32 bit application, I installed the i386 requrements: ...
3k views

### How to pass a list as function argument?

I have the following function lFreqPhylo[a_, Q_, b_, p_] := Sum[Log[freqFunction[r[[p]][[i]], L[[p]][[i]], a, Q, b, {i, 1, nbranches[[p]]}]; The objects L, r ...
577 views

### How can I speed up this code with multiple sum？

There are 4 variables in this multiple sum, therefore it may take a long time. I have run this program for 12 hours, but no result untill now. I want to know how to speed up this code. Any help or ...
244 views

### Exhaustive examples of variable replacement due to nested scoping constructs

Consider the following examples, where I have replaced dollar signs in the output by a D. ...
142 views

### Creating Do loop that cycles back to earlier values

I need to create a Do loop that distributes letters in a list of lists. I also need to be able to cycle back through to the beginning of the list. For example, I ...
137 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 $$\{\{2\}\},$$ \{...
226 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 ...
78 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 ...
1k 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 ...
84 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 ...
152 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 ...
386 views

### Numeric mixed derivatives

In short I need NumericCalculusND 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. ...
167 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 ...
636 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. ...
97 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.
764 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: ...
1k 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 ...
203 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"; ...
312 views

### Multiplicative partition function

I am trying to create a multiplicative partition function that would generate something like ...
80 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: ...
98 views

### Defining the function of list of parameters

I'm defining the functions in the following way ...
76 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, ...
886 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 ...
187 views

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] ...
35 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}]] ...
225 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 $n=5$: ...
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 ...
221 views

### Bug in ListVectorPlot?

Trying to evaluate the following expression kills my kernel (Mathematica 8.0.0.0): ...
1k 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 ...
589 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" ...
96 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 ...
423 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 ...
126 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"] ...
251 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: ...
518 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: ...
205 views

### Plotting Phase Space [duplicate]

I have these two Equations \begin{align} x'(t)&=\sin(y)\\ y'(t)&=\cos(x) \end{align} and I'm trying to plot the phase space(plane) for this system... I've tryed Equationtrekker but can't ...
203 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 ...
206 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, ...
62 views

### Quoting definition explicitly

I'm trying to quote a definition using DownValues, OwnValues, etc. Everything seems to be fine, except for temporary symbols' ...
216 views

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237 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: ...
2k 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 ...
177 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 ...
391 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 ...
151 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 ...
243 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 ...
75 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 ...
56 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] ...