7
votes
1answer
356 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
122 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}]] ...
0
votes
1answer
59 views

Visualizing vectors [closed]

How to visualize a set of vectors with 3 coordinates $(x,y,z)$, e.g.,$(1,1,1), (1,-1,-1),(-1,1,-1),(-1,-1,1)$? In fact there are many of them. I try the function "Graphic3D" with the following code ...
2
votes
2answers
142 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
120 views

Bug in ListVectorPlot?

Trying to evaluate the following expression kills my kernel (Mathematica 8.0.0.0): ...
0
votes
0answers
61 views

Inconsistent behavior of Assuming[] in combination with Simplify[]

The following integral gives the correct result ...
2
votes
1answer
137 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 ...
1
vote
3answers
122 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
86 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
243 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
88 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
121 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: ...
10
votes
3answers
419 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: ...
1
vote
0answers
72 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
123 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 ...
1
vote
1answer
53 views

sum polynomial H(x,y) [closed]

I want to write and evaluate an expression something like $$H_1=\sum_{i+j=0}^3 e_{ij}x^iy^j$$ or $$H=\frac{\sum_{i+j=0}^3 e_{ij}x^iy^j}{\sum_{i+j=0}^3 a_{ij}x^iy^j}$$ with correct syntax.
3
votes
1answer
182 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
47 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
176 views

Center Manifolds

...
8
votes
2answers
168 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
276 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
132 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 ...
0
votes
2answers
47 views

how to define roots of an equation as a function? [closed]

I need to solve an equation depending on 3variables in only one variables and define the roots as a function of the remaining variables? I used some thing like that: ...
2
votes
2answers
328 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
3answers
130 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
141 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
63 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 ...
0
votes
1answer
81 views

How do I show cross sections of a basic shape using calculus? [closed]

Assume I have an object whose radius is modeled by the function $x^2$. Using calculus and circular cross-sections, the object's volume is given by $\pi\int_a^b(x^2)^2dx$. But given an arbitrary ...
1
vote
1answer
48 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
193 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
34 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 ...
19
votes
2answers
447 views

High-quality RegionPlot3D for logical combinations of predicates

Unlike RegionPlot, RegionPlot3D copes poorly with logical combinations of predicates (...
0
votes
0answers
72 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
65 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
123 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
80 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 ?
1
vote
1answer
120 views

Calculate the algebraic multiplicity of known eigenvalues of a large, sparse matrix

I have a large (and sparse) matrix with size 1000x1000 -- 10000x10000. I believe i know all eigenvalues for the matrices. All entries are integers and so are the eigenvalues. I want to check this by ...
2
votes
1answer
139 views

Cropping a non-cubic lattice unit cell

I would like to crop the hexagonal close-packed system as a hexagon and not as a cube. I would like to use the following volumetricPlot already given on this ...
1
vote
1answer
71 views

ListPointPlot3D in a Manipulate

I have a program using Manipulate. The program given certain values will compute some values. I want these values to appear in a 3D list plot but the problem I am ...
1
vote
1answer
38 views

Evaluation of m.v is blocked by applying MatrixForm. Why? [duplicate]

I'm trying to understand what is happening in the notebook session below. I have a 2x2 matrix m = {{-1,-1}, {-1,-1}}. And a vector ...
3
votes
1answer
89 views

Export LocatorPane as image by button

How to Export LocatorPane as image by button or at least by something else? Kuba, thank you! Your method works in a simple case: ...
3
votes
4answers
300 views

Interpolating a plot with missing values

With data = {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {5, 5}, {6, 6}, {7, 5}, {8, 4}, {10, 3}, {10, 2}, {11, 1}} and ...
6
votes
1answer
224 views

Can Mathematica do two evaluations at the same time?

When one evaluation is running, if I want do another evaluation, Mathematica will put the second one in the queue and run it after the first evaluation finish. However, the first evaluation may take ...
1
vote
1answer
106 views
2
votes
1answer
180 views

Is there a better way to create my rotational-symmetric (180 degrees) rectangles?

I have created a simple way to create rotational-symmetric (180 degrees) rectangles, but my stuffit function bothers me. No matter what I tried, I couldn't get it ...
3
votes
1answer
264 views

Remove borders in a series of images

I have a series of mouse MRI images, here are two How can I automatically remove the metal cage around the mouse to make it look like this: The position of the cage is not always in exactly ...
3
votes
1answer
200 views

How do I built a zoomable Koch curve?

I'm new to Mathematica and my goal is to write a simple program in order to demonstrate self-similarity of the Koch curve by zooming in. Here is a good example of what I mean (it's a Java applet). I ...
3
votes
1answer
75 views

Highlight the same symbol throughout notebook

Once I saw people using Matlab use a keystroke shortcut that made all the same symbols as a selected symbol become blue. I am wondering is there is a function in Mathematica that is similar. If so, ...

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