# All Questions

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 ...
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: ...
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 ...
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, ...
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!
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 ...
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 ...
165 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] ...
375 views

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

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

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 ...
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 ...
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: ...
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 ...
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 ...
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, ...
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 ...
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 ...
217 views

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 ...
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 ...
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: ...
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 ...
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 ...
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 ...
137 views

### How to find a fit for a function?

I have the following function: ...

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