4
votes
1answer
1k views

Efficient implementation of cubic equation of state

...In this case the Peng Robinson Equation of State. Equations of state are empirical equations with parameters derived from experimental data. They are used to predict pure component and mixture ...
5
votes
5answers
2k views

Replace values which obey certain criteria

I'd like to replace all values in a list which obey one or more criteria with another value. Example: Replace all values>30 by 30. data={{3,35},{2,7}} ...
9
votes
1answer
233 views

Arranging elements in a Grid by drag&drop

I have some elements in a Grid. I want to change their positions within that Grid. Can I swap their positions just by dragging ...
1
vote
1answer
117 views

How to explain the results of the following integrals?

Why does the following program lead to different results of a21 and a211? ...
2
votes
1answer
121 views

Using EdgeList on a once empty Graph crashes the kernel

Note: this is fixed in version 9. Calling EdgeList on a non-empty graph which was previously empty causes the math kernel to crash. For example, ...
4
votes
2answers
131 views

Problems with setting style options

Consider the following: FirstOutput=Style["Test", FontSize -> 20] SetOptions[Style, FontSize -> 20]; SecondOutput=Style["Test"] I would like the string ...
3
votes
1answer
341 views

Creating multicolored meshed plots (connected scatter plots) using ListPlot

I would like to make colored scatter plots where the dots are connected by lines. I have tried the following, using Joined->True to connect the dots and ...
22
votes
3answers
844 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
472 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
372 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
181 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
637 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 ...
11
votes
5answers
5k 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
280 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
143 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
383 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
259 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
381 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
615 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
824 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
240 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
349 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
538 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
308 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? ...
7
votes
0answers
188 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
176 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 ...
9
votes
1answer
193 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
8k 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
330 views

Compiled version of (Norm/@coordinates)

Here I define (NormCoordinates). ...
3
votes
2answers
395 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
4k 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
227 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
275 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
193 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 ...
4
votes
1answer
3k 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
838 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
297 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
200 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 ...
19
votes
5answers
865 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
194 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
3k 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
240 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
467 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 ...

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