# All Questions

104 views

### Simple Jacobians, Gradients, etc. with arbitrary length vectors/matrices?

Is there any way (or a package built for it) can do simple operations with vectors and matricies of arbitrary size, but conforming extents? For the simplest example to test, given an arbitrary vector ...
194 views

### Why does Mathematica find a form for this general sum, but not for some special cases?

Today I found a Sum which Mathematica will simplify for a general parameter value $\nu$, but which will not simplify fully for special cases $\nu = 1, 3, ...$ despite the fact that the general answer ...
287 views

### Plotting a defined function gives different results from plotting the function directly

Consider the following piece of code: function[t_]:=Exp[-9 t^2]; LogLogPlot[{function[t],Exp[-9 t^2]},{t,.01,100}] I expect the two plots to exactly overlap each ...
716 views

### How does Mathematica estimate error on fit parameters?

When performing a fit using NonlinearModelFit (or any of Mathematica fitting functions, but I am particularly interested in nonlinear models), Mathematica makes a ...
162 views

### Notation for implicit derivative

Consider the following line of code: D[x == y^3 + x y, x, NonConstants -> y] The output would be: ...
108 views

### How do I operate on this list elegantly? [duplicate]

calibData = { {200, 10}, {100, 20} } MapAt[N, MapAt[Log10, calibData, {;; , 1}], {;; , 1}] I want to apply a base 10 Log to the first element of each tuple. ...
385 views

### How to represent a continuous monotonic phase of Airy functions?

Note: In this question I am concerned only with real-valued variables and functions. DLMF, §9.8 Airy Functions, Modulus and Phase, formula $9.8.4$ defines the phase of Airy functions: ...
281 views

### Taking real and imaginary parts of indexed functions and speeding up ComplexExpand

I am setting up a large system of ODEs and in order to use the IDA method (which is sig. faster for my system and thus attractive), I must split my equations into real and imaginary parts. I am ...
458 views

### Does anyone have experience with performing symbolic regression using Mathematica?

I understand that there is at least one Mathematica package, DataModeler commercially available for symbolic regression. I'm seeking any observations with this or any other similar tool. I'm ...
492 views

### How can I prevent Superscript from being interpreted as Power?

I have very strong desire to use superscript as the index of the variable. However, it looks like that the Mathematica automatically recognize the superscript as the power and I got message that my ...
86 views

### Help with Integrals (and conditional expectations) of the Beta distribution: Integrate[e^(az) z^a (1-z)^b, {z, 0, 1}]

I have a Beta distribution, and am interested in calculating expectations and conditional expectations. The domain on the distribution is $z \in [0,1]$ Ignoring constants of proportionality, the ...
162 views

### Pretty InputField

I'm trying to create a "template" notebook for myself. I want to get input from a single InputField, and then run a few operations on it. How can I make the ...
97 views

### List Manipulation matrices

I have the following two lists: List A: ...
63 views

### Using the error messages that gets generated while executing

While executing code it is normal to get the messages like shdw,argx etc. I wanted to know if there is anyway i can store all these messages into a array or a variable so that i can pinpoint where the ...
468 views

### How to write beveled fractions?

How to write beveled fractions like ${}^a/_b$? In contrast to $\frac{a}{b}$ and $a/b$ (see this question).
65 views

### what can be the reasons for webmathematica kernel to quit?

I am new to webmathematica. I wanted to know under what circumstances can a kernel quit the processing.
565 views

### Uniformly distributed n-dimensional probability vectors

What's the right way to generate a random probability vector $p={p_1,\ldots,p_n} \in {(0,1)}^n$ where $\sum_i p_i=1$, uniformly distributed over the $(n-1)$-dimensional simplex? What I have is ...
162 views

### Constraint on variables in summation

Is it possible to have a constraint on variables in summation of series just similar to pattern constraint e.g. ...
507 views

### Remove redundant dependencies from a directed acyclic graph

Given a directed acyclic graph, I want to remove all the edges $v_i \rightarrow v_j$ if $v_j$ is reachable from $v_i$ by some other path. Given the rich set of graph algorithms in Mathematica, what is ...
566 views

### Calling Mathematica from Visual Studio - example

I am trying to set up a connection between Visual Studio 10 and Mathematica 8.0 on a Windows system. I found several sources of information on the Wolfram website, but I get entirely lost. Most of the ...
84 views

### Stylesheet modifications mimicking Stack Exchange styles

I find myself frequently highlighting and formatting portions of text cells in a Mathematica notebook. Bold and Italic typesetting is easy to handle but I would like to use ...
57 views

### Getting InputStream errors when including a call to ElementData within an Import definition

So I am writing an ImportExport converter for a common chemistry file format, and I've run up against a problem that seems to be about shared streams and whatnot. ...
199 views

683 views

### Counting sublists containing 0

Given a list: data = {{0, 2}, {0, 0}, {1, 0}, {1, 2}, {2, 3}}. I would like to count the number of sublists which contain zero. ...
240 views

### How to read image files in Analyze 7.5 format?

I am using GATE/Geant4 for simulating photon beams interacting with matter. For 3D dose distributions, GATE outputs the data into an Analyze 7.5 format [1]. I was wondering whether there exists a ...
119 views

### Keep order of mulciplication in Matrix production

{{λ E, B}, {λ A1, λ E}}.{{E, 0}, {-A1, E}} \begin{align*}\left(\begin{array}{cc} E^2 \lambda -A1 B & B E \\ 0 & E^2 \lambda ...
54 views

### Am I missing something in this integral?

I am trying to solve this simple integral: ...