22
votes
3answers
938 views

Emulating R data frame getters with UpValues

What's the best way to emulate R's data frames functionality? This includes the ability to select rows and columns in a 2-dimensional table by the string identifiers positioned typically in the first ...
3
votes
2answers
581 views

Defining a function using Series? [duplicate]

Possible Duplicate: General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it? I need to define a function using the output of series, i.e. ...
2
votes
0answers
382 views

Simple contour integral with a parameter gone wrong

I run into the following problem, I tried to evaluate a very simple integral: Assuming[ a > 0 , Integrate[Sin[a*s]/(s - I)^2, {s, -Infinity, Infinity}]] ...
2
votes
1answer
199 views

Multi-Selection dynamic menus

I'm looking to create dynamic menus with multiple options, and would allow multiple selections. For example, mousing over an object (let's say a black circle of rad 1), a menu would popup at ...
6
votes
2answers
719 views

Implicit Equality and RegionPlot

I have the following problem: I would like to do a RegionPlot like RegionPlot[F[x,z,y]<1,{x,0,1},{y,0,1}] The problem is that the variable z is an implicit ...
12
votes
5answers
6k views

Filling between boundaries

I would like to visualize what it graphically means to integrate between two boundary values. Therefor I'd like to make a Filling between these two values. Is there a way to get this done?
7
votes
2answers
281 views

How to simplify the integration result of the following program?

In the following program, the fec[x] is a function depending on $x$ while q3[t] and q5[t] ...
4
votes
3answers
1k views

How do I make a log plot where the plot is logarithmic in the distance from the X-Axis (including negative values)?

For example, if I were to do a plot of Sin[x], I would get what looks like a Log plot of Sin[x], with another log plot of ...
2
votes
1answer
146 views

semantics of `ContinuousAction` on a slider. Mouse release

I needed to make 2 slider inter-dependent. Slider b in this example can't be larger than slider a. When I move slider ...
2
votes
3answers
446 views

How can `SquareWave` be used as the input in `OutputResponse`?

I'd like to compute the response of a TransferFunctionModel when driven by a SquareWave. Here's a simple example, ...
23
votes
4answers
1k views

What is the fastest way to count square-free words?

Background A word is a string of letters in an alphabet. A square-free word has no adjacent repeating substring. For example, (in the ternary alphabet of {0,1,2}) the words 00, 012121, and 0212012021 ...
4
votes
2answers
272 views

How can I emit a sound only during a mouseover?

Emitting a constant sound or note (no interruptions) for a fixed duration is easy, but a dynamic duration, not so easy.
2
votes
4answers
400 views

Building a list recursive with one or more arguments

Consider the following: data={a,b,c,d}; res={{a,b,c,d},{b,c,d,e},{c,d,e,f},{d,e,f,g}}; The idea is to define a function ...
3
votes
2answers
686 views

Getting consistent Ticks lengths and TickLabels positioning

From the Documentation, Tick mark lengths are given as a fraction of the distance across the whole plot. I wish to have identical tick mark lengths for both horizontal and vertical ticks and I ...
2
votes
2answers
971 views

Interpreting the interpolating function and saving data to plot with external program

So far I have been solving non-linear pdes with NDSolve and then plotting the result with the in-built Plot3D and ...
14
votes
6answers
2k views

Counting negative values in list

I would like to count the negative values of a list. My approach was Count[data, -_] which doesn't work. How can I tell Mathematica to count all numbers with ...
7
votes
2answers
263 views

Clean up list of partial outputs for memory

Context I run long Mathematica sessions; sometimes I have Output up to Out[3000+]. Hence I would like to be able to clear out some previous outputs which do use lots of memory. Attempt I am aware ...
7
votes
2answers
355 views

find subsequences of constant increase

A list like l = {0, 1, 2, 3, 4, 5, 7, 9, 12, 13, 18, 19} may have subsequences of constant increase, $a_{n+1} = a_n + k$. For example: ...
19
votes
3answers
2k views

How to make hollow polyhedra?

I found a version of the Mathematica spikey in 3D printable format (STL) at the Shapeways site that was hollow. Here it is when viewed in MeshLab: You can see there's a bit cut out of the end, and ...
6
votes
1answer
620 views

Import numeric values from XML

I am trying to import data from an XML file and then perform calculations on those numeric values. When I import the data the values seem to be stored as strings. I tried using a ToExpression ...
4
votes
2answers
329 views

Implementation of builtin function Fold

In the documentation for fold, it says Fold[f,x,list] gives the last element of FoldList[f,x,list]. But this is surely not the way it is implemented, right? ...
8
votes
0answers
192 views

Socket communication and player pro

I'd like to create a simple communication channel between MMA and the animation package 'Maya'. This is possible over sockets ( very simple, just sending and receiving strings). I've got this working ...
4
votes
1answer
177 views

Finding mappings between expressions

Suppose we have an expression of the form: $j=\frac{A\left(t\right)}{B\left(t\right)}=\frac{C\left(s\right)}{D\left(s\right)}$ That is, $j$ can be expressed either as a function of $t$, or as a ...
11
votes
1answer
227 views

Map efficiently over duplicates in list

I am interested in mapping a function, f over a (long) list which contains duplicates. Since this function takes a while to evaluate I would like to make use of ...
4
votes
1answer
10k views

Plot Log scale on X-Axis?

There's documentation on how to do a LogPlot with respect to Y-axis, but how would you do the same for the X-axis? Is there some Plot option? For example, here are some examples that plot Log scale ...
8
votes
1answer
336 views

Compiled version of (Norm/@coordinates)

Here I define (NormCoordinates). ...
3
votes
2answers
403 views

Horizon Plots in Mathematica?

I am trying to create horizon plots in Mathematica similar to what is described here: http://timelyportfolio.blogspot.com/2012/08/more-on-horizon-charts.html Any suggestions how to approach this?
6
votes
2answers
2k views

NonlinearModelFit Problem

I have some problems with the NonlinearModelFit: NonlinearModelFit[data, A (1 + Cos[a x]) + B (1 + Cos[b x]) + c , {A, B, a, b, c}, x] The model should fit my ...
8
votes
3answers
5k views

How to find the nth derivative?

This question is not the same as my last one. How do you find the $n$-th derivative where $n$ is a variable? For example, you can find the nth derivative for a specific $n = 3$ ...
3
votes
1answer
263 views

How to iteratively display the nth derivative?

I am new to Mathematica, but not so new to programming. What I'd like to do in Mathematica (not using an API) is to display on each line, the nth derivative of a function, e.g. for n = 1..10. Is there ...
2
votes
3answers
287 views

Is it possible to use Composition for polynomial composition?

I want to do this: $P = (x^3+x)$ $Q = (x^2+1)$ $P \circ Q = P \circ (x^2+1) = (x^2+1)^3+(x^2+1) = x^6+3x^4+4x^2+2$ I used Composition for testing if that could ...
7
votes
1answer
195 views

How can I specify a numerical order for variables?

I need to specify that a variable is less than another, and greater than yet another, in a Mathematica program, because I will later apply a test to them that will determine what functional form to ...
5
votes
1answer
4k views

Can Mathematica help to rearrange an equation?

I have an equation which I want to rearrange so one variable is on the left side by itself. Normally, I would do this with basic algebra and identities. However, is it possible to use Mathematica to ...
27
votes
4answers
3k views

How to create this four-dimensional cube animation?

This is a tesseract, a four-dimensional cube, which contains two cubes. Here, each side length of the smaller one is 1, while the side length of the bigger one is 2. How do make I it? I am still ...
3
votes
1answer
963 views

GridLines at TickPositions

How can I force the GridLines to be at the positions of the Tick marks? A simple code, FrameTicks -> Automatic and ...
6
votes
1answer
325 views

ESRI shape files

ESRI shape files (shp): importing the polygon data can yield a very large list. It is computationally intensive rendering the polygon. I have been trying to convert to ...
11
votes
2answers
214 views

Globally loading packages while using a CellGroup as the default context

I have a notebook I wish to set up where the sections are conceptually related to each other. But, I wish to isolate them from each other programmatically, so that they do not interfere with one ...
20
votes
5answers
1k views

How do I reassign canonical ordering of symbols?

I have a big polynomial that evaluates to: $$A^2 e^2 \phi ^- \phi ^++A e \phi ^- \phi ^+ c_{2 w} g_Z+\frac{1}{2} A e g h W^- \phi ^+ +\ll13\gg,$$ which is supposed to represent some terms in the ...
8
votes
1answer
3k views

How do I create and use Mathematica packages?

I have created a package following the tutorial in Mathematica 8 virtual book. However this tutorial is quite, let's call it, "short". I have a TestPackage.m file: ...
4
votes
0answers
202 views

Unexpected behavior of GeometricTransformation

I have the following mapping on the complex plane: $$ z \mapsto \tau \mu z-1, $$ where $\mu$ is complex, $\tau$ is real number. I want to draw the image of left unit semidisk and play with $\tau$. ...
12
votes
3answers
4k views

How to express ticks in scientific form? [duplicate]

I want to express the ticks in scientific form. I tried two ways as following ...
2
votes
2answers
249 views

How to clear variables in a manipulate without enabling dynamic content?

I have a series of variables that will plot the number of straight segments along a curve, thanks to the help from here on one of my previous questions. I can create a working Manipulate command from ...
12
votes
1answer
549 views

Lazy lists of Tuples and Subsets

I'm trying to build a lazy list that evaluates the n'th m-tuple or subset of a given list using Mathematicas ordering without calculating all the Tuples. The purpose is to allow for example the ...
5
votes
1answer
326 views

Basic question about Dynamic

Please consider the following: ...
5
votes
2answers
797 views

How to group the powers of one variable?

Consider the following expression: $\sqrt{a x} \sqrt{b x}$ What do I use to make it simplify to: $\sqrt{ab} x$ I tried actually everything (Simplify, FullSimplify, Collect and so on...) and such ...
8
votes
0answers
2k views

Integro-differential equation

I have to numerically solve a nonlinear partial integro-differential equation using Mathematica. This is my equation, $$\frac{\partial y(x,t)}{\partial t}=\int_{-\infty}^\infty K_0(|x-u|) ...
4
votes
1answer
282 views

Attaching WolframAlpha data

I have used WolframAlpha since it was launched (now a pro member) but am new to Mathematica 8. Is there a way to automatically add data from WA to a Mathematica dataset? For example, what if I ...
9
votes
2answers
3k views

Problem with Financial Data

I'm following http://reference.wolfram.com/mathematica/ref/FinancialData.html I get the following: In[6]:= DateListLogPlot[FinancialData["^DJI", All]] During ...
8
votes
3answers
679 views

how to efficiently apply function to all pairs of a set (and collect the results)

To build a graph, I need to apply a function f[a_, b_] to all pairs of a list (3500 elements). The function itself returns a link ...
2
votes
1answer
224 views

copy paste merging expressions

I ran a solve to evaluate a few linear equations, Solve[{some eqns},{A0,B0,c0,d0,e0}] and then in the output I got: ...

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