0
votes
2answers
1k views

Eigenvalue problem and plotting its eigenfunctions [duplicate]

How many different ways can one solve an eigenvalue problem and plot its corresponding eigenfunctions in Mathematica? For example for Harmonic Oscillator? Which one is the most accurate one? Thanks ...
0
votes
0answers
52 views

Hide your controls inside Manipulate [duplicate]

I didn't find any topic that could help me; I hope this isn't repeated. I just want to show a control if a specific option is selected inside a popupmenu: ...
4
votes
1answer
168 views

Control over the way matrix is displayed

I am wondering how to change the output format in Mathematica. For example, I have $x=\binom{3}{1}$ and $y=\binom{2}{5}$, and I want to find what linear combination of $x$ and $y$ produces ...
3
votes
0answers
255 views

Understanding performance: graph connected components

I need to analyze directed graphs with 10M edges, 1M vertices, and 300K strongly connected components, so that the largest one contains 400K vertices. I read some explanations of Leonid Shifrin here, ...
2
votes
2answers
165 views

Create a Figure with a sequence of Balanced Binary Trees

I would like make the attached image by Mathematica. someone who could help me? Thank!
2
votes
0answers
50 views

Sending RObject to RFunctions

I want to realize function from some R package in Mathematica. First load RLink and package what I need ...
20
votes
6answers
3k views

Best way to extract values from a list of rules?

Mathematica has a lot of list manipulation functions, and, also because I don't work with lists often, at times I'm a bit lost. I'll find a way, but I'm sure it's not the most efficient. Case in ...
6
votes
1answer
165 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] ...
7
votes
1answer
375 views

What are \[InvisiblePrefixScriptBase] and \[InvisiblePostfixScriptBase]?

In the non-printing characters documentation, I see two named characters that are largely undocumented: \[InvisiblePrefixScriptBase] and ...
3
votes
3answers
276 views

How can I extract multiple spans from a list?

I know in Mathematica, I can do A = Range[100]; B = A[[50 ;; 60]] B will then contain the 50th through 60th elements of A. Now, what if I wanted B to take 10th ...
0
votes
3answers
808 views

Solving One Equation with Two Variables

I am trying to solve an equation with two variables. It is the last step in the process of using the method of undetermined coefficients to solve a nonhomogeneous differential equation. The equation ...
1
vote
1answer
269 views

How to use Button as a control in Manipulate

I am trying to use Button as a controller in Manipulate. I have done some thing like this: ...
3
votes
1answer
150 views

Table with some editable cells

I have a table: I want it to be editable only where the zeros appear. I read this post Generating an editable table that can be used as input because it's almost exactly what I want, but I couln't ...
1
vote
2answers
114 views

Clearing arguments passed to a Module

Is there a possible way to clear the arguments passed to a module to release some memory. I believe that arguments passed to modules are passed by value rather than pass by reference. e.g. I have the ...
2
votes
1answer
354 views

Stacked bars in a barchart with individual and overall labels

There are a lot of questions here about formatting of barcharts, but I couldn't find one matching mine. I seek to display data in stacked format, labeling each component of the stack and the total for ...
2
votes
3answers
195 views

Using Part rather than Extract

In my work I found that I needed the Extract function. However I was wondering if there was a way to use Part. Assume that ...
0
votes
1answer
118 views

Tab between elements in a GUI layout

If I have a bunch of input fields, I can tab between them quite conveniently, but if I want to navigate between the input fields and another element (in my case, a button), I have to click on the ...
5
votes
3answers
335 views

How to change the number of markers in Plots?

Two questions, but I am not sure whether they are already answered or not. How can I create PlotMarkers (in ListLinePlot) with ...
2
votes
0answers
81 views

RDPStruct.exe: what is it and why are there so many?

I have an old (v7) webMathematica system running and it seems to generate a lot of RDPStruct.exe processes. First, what does this "Converter" do? GIF.exe and JPEG.exe are obvious, but "RDPStruct" ...
0
votes
0answers
432 views

NDSolve gives wrong results for “stiff system”

I have a physical problem in which I want to solve for c[e] as a function of e, where c is ...
3
votes
1answer
76 views

Convert an expression's symbols of form a$x to a[x]

I want a function that takes expressions of the following form: a$x and converts them to a[x]. In particular, consider the ...
0
votes
1answer
70 views

Inequality test returned unevaluated

I tried, Refine[Sin[k]^2/(k^2 + k + 1) < 1/(k^2), Element[k, Integers]] $\frac{\text{Sin}[k]^2}{1+k+k^2}<\frac{1}{k^2}$ It returns unevaluated. I ...
2
votes
0answers
21 views

In a Function, how to Ensure Code Runs Prior to an Abort [duplicate]

Is there a way to set aside some code in a function that will be triggered to run if the evaluation of the function is aborted by a user? Specifically, I have a function that has to open a log file to ...
0
votes
2answers
192 views

How to control the layering of graphics displayed with Show

I am trying to combine two graphics objects using Show. The first one is an isosurface: ...
0
votes
1answer
143 views

Using a LocatorPane

I have a network of a power grid where the edge are the power lines and the vertices are loads or generators. I was wondering how I can import an image into Mathematica to derive some sort of ...
1
vote
0answers
77 views

How to find a scaling parameter in matrix inversion process by MMA?

I simply would like to find the inverse of a given matrix $A$ by the iterative method $X_{k+1}=X_k(2I-AX_k)$ using $X_0=\frac{1}{\sigma_{max}^2}A^*$. An example is as follows ...
1
vote
1answer
826 views

How can I obtain Wolfram Alpha's “alternative forms” of an expression inside Mathematica?

When I type in Wolfram Alpha, say, cos(a+b) or cos(a+b)^2 or (OK this next one can easily be obtained in Mathematica, ...
2
votes
2answers
375 views

How can I propagate an asymmetric error in a function about the central value?

If I have some asymmetric error about the central value in x and y, then how can it be propagated in a function f[x, y, z]? For example, given ...
1
vote
0answers
194 views

Code for solving numerically an integro-differential equation

First of all, I want to greet the community. This is my first question, but I hope I will be able to help answering others members questions, although I am quite new working with Mathematica. I would ...
2
votes
1answer
217 views

Compute symbolic Expectation of a summation

I am required to computed following Expectations : $E[\displaystyle\sum\limits_{i=1}^N \frac{X_{i}}{N}] = \bar{x}_{0}$ & $E[\displaystyle(\sum\limits_{i=1}^N \frac{X_{i}}{N})^2] = ...
8
votes
2answers
367 views

Mathematica outliner's capabilities

As my notebooks get larger, I often try to organize them with titles/subtitles etc, structuring them as an outliner (http://en.wikipedia.org/wiki/Outliner) This also helps me as I try to structure a ...
2
votes
1answer
257 views

Segment parts of a picture

I remember that there was some thread of this sort, but I could not find it, so I hope it's ok to open a new thread. I want to segment pictures of the brain, i.e. I only want the area within the ...
1
vote
1answer
74 views

Devising a sparse array rule

Suppose I have a matrix A={{1, 2}, {3, 4}} that defines the positions of non-zero values in a sparse array: ...
0
votes
1answer
104 views

Solving a differential Equation

I am trying to solve -D[((α + γ/2)*a + β/(2*a) - R*a^3)*p[a], a] + 0.5*D[(γ*a^2 + β)*p[a], {a, 2}] == 0 with DSolve, but it ...
0
votes
0answers
68 views

Expectation taking unusually long to evaluate

I am trying to evaluate an expectation, but it is taking an extremely long time although the expression itself should not be too complicated. My code is ...
10
votes
1answer
749 views

Poor performance from Graphics3D

I wrote a game -- 2048,Some codes are from http://blog.wolfram.com/. My codes are in notebook downloads I added code so that the game can play in 3D form, but when I play it, I find that it is too ...
1
vote
1answer
332 views

Interpolate a curve in 3D

I have a sequence $\{(x_k, y_k, z_k)\}_{k=1}^n \subset \mathbb{R}^3$, all points along a path represented by the function $\gamma \colon \mathbb{R} \to \mathbb{R}^3$, which maps the distance along the ...
4
votes
3answers
143 views

Is there an equivalent of Sum for And?

Is there an equivalent to Sum for And? That is, just like instead of ...
3
votes
0answers
69 views

What SampleRate and SampleDepth does Mathematica use on output?

The Play function will happily accept arbitrary values for its SampleDepth and SampleRate ...
52
votes
3answers
4k views

Is Mathematica an Implementation of the Wolfram Language?

I am trying to figure out what the announcement of the Wolfram Language means for Mathematica. Is Mathematica an implementation of the Wolfram Language, or is it something else?
3
votes
1answer
90 views

Extract differential operator from differential form

Let's say I have : a*u''[x]+b*u'[x] where a and b are constant I would need to get ...
0
votes
0answers
86 views

Using Wolfram Language without Raspberry Pi [duplicate]

What are the different ways I can start using Wolfram Language even though I dont want to use Raspberry Pi? Are there any convenient ways? I actually have a raspberry pi but I am trying to find ...
4
votes
3answers
2k views

Smooth 4D (3D + color) plot from discrete points

I have a file containing isosurface $\{x,y,z,F\}$ data (around 9000 points). My goal is to generate a smooth (NOT a discrete set of points!) colored surface using ...
2
votes
1answer
112 views

Can I use Map here rather than Table?

I've got something that works, but it seems like it would be "nicer" if I didn't have to use Table (or For, etc.). I've got 3 Excel files, each with multiple sheets. Each file also has a sheet ...
4
votes
2answers
163 views

Replacing one element of list

I have a list of sequences of x's and y's. I want to switch the last position to the "opposite" symbol - if ...
0
votes
1answer
89 views

Strange behaviour of “Make Table” with exponential function

I am trying to create a simple interpolation of 1-Exp[-x^2] function, over the logarithmic grid, but I am stuck due to some unexpected behaviour: ...
1
vote
1answer
126 views

How to obtain a useful answer from integration when Simplify is insufficient?

I have been trying to integrate a function AND get an output that is sufficiently simple as to be usable. Simply using the Simplify and ...
1
vote
2answers
94 views

Using Combinatorica`ListNecklaces in v9

I am using Mathematica for visualization of DeBruijn graphs. However, I am having a bit of trouble using ListNecklaces. I want to know how many cyclic shifts of ...
2
votes
2answers
127 views

How to combine notebook into one cell

I want to have my entire notebook be a conditional while statement. However, I don't want to merge all of my cells together, as it is a long and detailed process. Is there a way to create another cell ...
0
votes
1answer
137 views

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