10
votes
3answers
940 views

Difference between @ and @@

I am confused by the commands @ and @@. From the documentation, I learnt that @@ is the ...
1
vote
0answers
51 views

Quit Kernel Shortcut [duplicate]

How could I set a Keyboard shortcut for the Quit Kernel -> Local command? I find really disappointing to open the Evaluation menu any time!
0
votes
0answers
248 views

Linear Stability Analysis Routine. Normal Modes in NDSolve

I want to make the linear stability analyis of a nonlinear system of PDEs. So for example then I want to plot what happens to the amplitudes of the modes. To do that I need to solve my equations with ...
0
votes
1answer
408 views

Solving recurrence relationship using iteration

I am trying to create a Mathematica function that basically splits up a continuous function (in this case a physical potential) into steps (strips as it were) and returns the value of the function at ...
0
votes
1answer
479 views

FindMinimum produces error message

I'm trying to solve a logistic regression problem using Mathematica -- more to improve my Mathematica skills than to solve the problem as I have already solved it using Octave. The problem I am ...
10
votes
3answers
547 views

How to visualize the interior of a complicated 3d plot

I have an external data file (can be downloaded here: link 1 or link 2) which contains a dense grid of initial condition in the (x,y,z) space. I read it with Mathematica and plot these initial ...
1
vote
2answers
144 views

Add a letter to a variable name from a list

Basically I am searching for a way to add the letter u to an existing list of variables {a,b,c,d} to obtain the variable list ...
3
votes
1answer
442 views

Plotting a Gravity-Field [duplicate]

I try to plot a 2D gravity field or something similar in the form like $r/|r|^3$ with the standart builtin VectorPlot function: ...
4
votes
2answers
233 views

Dimension of an algebraic variety

I would like to compute, using Groebner bases, the dimension of the variety defined by a set of polynomials in several variables. In the wikipedia page the method is described, and an implementation ...
0
votes
0answers
126 views

Positioning Labeled points in ListPlot gives unexpected results and errors

Original question can be seen in the edit history.... UPDATE: a simpler example - same "problem" ...
0
votes
2answers
141 views

A function that (also) changes a replacement rule

I'd like to write a function operating on a list, returning a list, but also changing a replacement rule. Let's say I have a list of replacement rules: ...
4
votes
1answer
395 views

Von Mangoldt function

Can anybody evaluate the following sum for me $$ \sum\limits_{n=2}^\infty(-1)^n\left(\frac{\psi(n)}{n}-\frac{\Lambda(n)}{2n}\right) $$ where $\psi(n)$ is the Chebyshev function and $\Lambda(n)$ is ...
0
votes
1answer
148 views

Fourier-Analysis How to display every period correctly? [duplicate]

I want to express a function as a sum of fourier series. I tried the code below. It works. But only get one period (from 0 to 1). How to display every period correctly? ...
0
votes
1answer
117 views

Showing the value a plotted function achieves at the right-most point of the plot domain

I'm plotting results from NDSolve, and I'd like to clip them with their value at the point where the line is clipped. So where the curve ends at the edge of the plot, there would be a number ...
2
votes
1answer
456 views

FindRoot giving false roots with Bessel Functions

I have read in some places about the errors associated with FindRoot, but the closest thing I can find on this website seems to be due to the imaginary unit. I am dealing with what should be a ...
0
votes
1answer
354 views

Code to give center of circle given three points in 2D? [duplicate]

does anyone know how to make a function C(p1,p2,p3)=center of circle that goes through p1, p2, and p3? This is in 2D Sorry this is poorly written but I ...
2
votes
2answers
175 views

Are there built-in functions for testing if a point lies within Graphics3D primitives?

I noticed in this question, Behavior of Graphics`Mesh`InPolygonQ with self-intersecting polygons, that Mathematica has some "psuedo-hidden" functionality for allowing one to quickly perform a winding ...
0
votes
2answers
130 views

Drawing a large set of Graphics3D cylinders provided a set of cylinder specifications in a list

I'd like to draw a large number of 3D cylinders using Graphics3D. My list specifying the cylinders has elements that look like the following: ...
0
votes
1answer
82 views

How can I influence the elements plotted in a BubbleChart depending on the tuple plotted?

In a BubbleChart, how can influence the elements plotted depending on a value in the tuple plotted? I want to create a BubbleChart from the following data: ...
0
votes
1answer
198 views

Run FileSystem Remotely and Front End/Kernel Locally

Is there a way to run both the front end(& kernel) locally while the having Mathematica's filesystem(inode's at minimum) reference another os's filesystem? For example currently I run ...
0
votes
1answer
88 views

Collecting variables from Subscript

I have followings set: t = Transpose[{x[#] & /@ Range[20], RandomInteger[15, 20]}]; Subscript[#[[1]], #[[2]]] & /@ t The code is just to build my set.So ...
0
votes
1answer
126 views

Make the y-axis of a plot be in terms of an arbitrary parameter instead of a number?

Sorry if the title is wordy. Basically what I am asking would probably be easier if I just use an example. Say I wanted to plot f(x) = Asin(x) and have the graph come up with the sine function, and ...
1
vote
2answers
207 views

Opacity and overlapping points on ListPlot3D

I am plotting a dataset on ListPointPlot3D, and in order to give an idea of density of points I used opacity of 0.5. The problem is that that while the opacity of points behind one another is added, ...
8
votes
1answer
636 views

How to calculate the $H_2$ and $H_\infty$ norms of TransferFunctionModels or StateSpaceModels?

Lets assume we have a system model: ...
6
votes
2answers
2k views

Paths integrals in the complex plane

I can't find how to calculate path integrals of complex functions in the complex plane. For example: $$\oint_{\mid z \mid =2}\frac{1-e^z+z}{z^3 (z-1)^2}dz$$
0
votes
1answer
84 views

How to close all other MathKernel before opening the new one?

I use MathLink to call Mathematica from C program. After any opening to Mathematica, I do close the connection. However, I don't know why some connections are ...
2
votes
2answers
123 views

Definite Integral. Perfomance problem

I have a notebook in Mathematica 4. I'm trying to convert it to use in Mathematica 9. One of the problem is the long computation of definite integral. In Mathematica 4 the result of the following code ...
2
votes
0answers
194 views

Symbol with Subscript but no quotes in it!

If I use the following function to define me a fancy subscript: ...
2
votes
6answers
226 views

Manipulating List

I have a list: b={{1, 1}, {2, 2}, {3, 3}, {5, 5}, {6, 6}, {8, 8}, {10, 10}} I want to insert the elements in this list: ...
1
vote
1answer
744 views

How to rotate the z label in 3D plots

Let's take the following simple and funny case ...
5
votes
1answer
113 views

Amount of k-sized not-duplicated subsets of subsets of pair with disitinct sorted integers

I have a list, L, of this kind ($n\in \mathbb{N}$): L=Sort[RandomSample[Subsets[Range[n],{2}],RandomInteger[{1,Binomial[n,2]}]]] S contains any k-sized subset ...
1
vote
2answers
246 views

How to simplify an expression with square roots?

The expression $\sqrt{L^2 M+\sqrt{L^2 (-J^2 + L^2 M^2)}}/\sqrt{2}$,can be simplified into $\sqrt{L}(\sqrt{LM + J}+\sqrt{LM - J})/2$, but how can I obtain this result with Mathematica? That is, how ...
2
votes
4answers
156 views

Get the first positive coefficient in polynomial?

I have Polynomial $F(x) = \sum_{i \leq n}{a_ix^i}$. How to get the first $a_i > 0$? Thanks,
1
vote
0answers
72 views

The number of real values assumed by combinations of complex roots of a decic

Define complex conjugate as the pair of complex numbers $a+bi,a-bi$. Assume you have 5 such pairs and they are the 10 roots $x_i$ of a 10th-deg equation with integer coefficients. In general, how many ...
14
votes
1answer
269 views

How to programmatically remove menu items

I would like to do the opposite of what is described here. So rather than add a menu item I would like to programmatically remove one (or more). So given a knowledge of the structure of the menu *.tr ...
0
votes
2answers
168 views

What's wrong with my graph input?

So I saw this picture on my book and it was left as an exercise to figure out. This is what I have so far, but I'm not sure where I went wrong. ...
0
votes
0answers
43 views

Generate effective C/Java code (minimizing operations) [duplicate]

Is it possible to generate C/Java code with Mathematica so that it minimizes number of operations performed? For example, for matrix inverse or determinant? With good caching variables?
5
votes
1answer
74 views

Details of automatic cell-grouping w.r.t. cell-style

What determines how a specific cell-style influences grouping of cells? For example "Text" following "Subtitle" is grouped but ...
6
votes
9answers
942 views

combining and comparing lists

I have 2 lists (of lists), where most of the contained lists match. That is, the lists contained in list1 mostly match the lists contained in list2. In this simplified example each of the inner ...
7
votes
3answers
319 views

Using NSolve in the complex plane

I am trying to find numerical values for $\Im\ e^{\frac{1}{2} +i\ y} = \Im\ \zeta(\frac{1}{2} +i\ y)$ for a given range. I have tried: ...
2
votes
1answer
350 views

Calculate scalar potential from electric field

Is it possible for Mathematica to solve an equation like $\nabla f(\mathbf{r}) = - \mathbf{E}(\mathbf{r})$ for $f(\mathbf{r})$? I tried ...
0
votes
1answer
1k views

Best way to compute row eigenvectors

Without qualification, the term eigenvectors (of a matrix) refers to the column eigenvectors (of a matrix) and can be directly computed with Eigenvectors[]. To get ...
5
votes
2answers
548 views

Table of Variables

I use a list of variables {x1, x2, x3} to Solve a particular set of equations. I am now trying to generalise this depending on ...
2
votes
2answers
324 views

Colors for multiple piecewise functions

I have the following $3$ piecewise functions, and I would like that f1, f2 and f3 have $3$ ...
4
votes
1answer
205 views

How to prevent axes label and tick labels from being placed inside a 3D plot

Consider the following toy-code: ...
1
vote
1answer
120 views

Caching data in Mathematica package

Consider the following: m=Quantity[1,"meter"] If I run the package, it will return 1m But when I load the package, the ...
5
votes
1answer
198 views

WhenEvent method with 3 conditions

I am trying to solve system of differential equations below $$x''(t)=-2.25cos(1.5t)-x(t)-x'(t)$$ $$y''(t)=-1.125cos(1.5t)-4y(t)-y'(t)$$ $$z'(t)=\begin{cases}x(t)-(1+y(t)), & \text{if } ...
14
votes
5answers
387 views

Partitioning a list of numbers the Mathematica way

I have two sorted lists, one list will be called the "fences" and the other the "values" Fences could be: $\{1, 5, 9, 14\}$ Values could be $\{-1, 1, 3, 4, 6, 9, 10, 13, 14, 15\}$ I want to ...
9
votes
2answers
427 views

Front end typing lag

Under Windows 7 I frequently get serious keyboard lag. My home machine (Windows XP) NEVER lags. I was able to improve things somewhat by running Mathematica as Administrator, but this only went so ...
2
votes
1answer
50 views

Suspend spacing between Repeated and number

The spacing of the first expression includes extra space before the 5. I would like to have the same spacing as the second line. ...

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