7
votes
2answers
207 views

How to make a point's position time-dependent given a formula for the next step?

I've made a program that is just some points on a plane. Red points are cops and green points are robbers. Each point has a vector indicating where it is going to be in the next step of $t$. Right now ...
7
votes
6answers
184 views

How to join held Lists?

Let's say I have a = Hold@{2+2} b = Hold@{4+4} How can I get Hold@{2+2,4+4} ie join the two held lists ? More ...
7
votes
2answers
237 views

Programatically adding/retaining comments within a nested list

Is it possible to convert the following list of strings to computable numbers with the comments preserved? ...
7
votes
2answers
1k views

How do I simplify a vector expression?

I am doing vector analysis. I have figured out that the following expression won't be simplified in Mathematica: Simplify[Dot[x, y] - Dot[y, x]] I think the ...
7
votes
3answers
379 views

How can I find the vertexes of a Polygon?

I made a polygon with the following vertexes : ...
7
votes
3answers
282 views

how to read in a file in the same directory?

Now I am writing a small package. I have written several files and put them in the same directory. And some files need to read in or include another file in the same directory. But when I simply write ...
7
votes
1answer
182 views

Prevent interdependence of controls

My question is probably best illustrated with this small sample code: ...
7
votes
1answer
298 views

How to create a multi-selectable setterbar with colored buttons

Background: consider the following code-snippet. ...
7
votes
3answers
298 views

Why can't D[] be used in place here? [duplicate]

Possible Duplicate: General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it? Beginner question: Why can't I use ...
7
votes
5answers
2k views

Notation of partial derivative

I want to write partial derivatives of functions with many arguments. Why is it that when I type f[x,y] ctrl+6 (0,1) it turns out to be bad syntax? The output of ...
7
votes
2answers
582 views

Entering block matrices for an arbitrary matrix size

Background: How to enter matrices in block matrix format? and the following: I want to create $$ f(A,t) = \left [ \begin{matrix} A & t \\ 0 & 1 \end{matrix} \right ] $$ where $A$ ...
7
votes
2answers
254 views

Revert FullForm-ed text to prettyprinted

Sometimes strings in a notebook/package file end up garbled due to some unknown/unintentional conversion of the expression/cell/notebook. I could not find a way to revert such unreadable text to its ...
7
votes
3answers
697 views

Why don't * and ^ work as I expected on matrices?

For example, this input... {{1, 2}, {3, 4}}*{{1, 2}, {3, 4}} produces this output... {{1, 4}, {9, 16}} and this input... ...
6
votes
2answers
559 views

Finding differences between Pi with varying number of decimals

I have the following code In[32]:= N[Pi, 2] Out[32]= 3.1 In[33]:= N[Pi, 1] Out[33]= 3. In[34]:= N[Pi, 2] - N[Pi, 1] Out[34]= 0.*10^-1 Why can't Mathematica ...
6
votes
5answers
244 views

Manipulating a sublist based on position

I have a huge list with huge sublists of the form list={{a,b,c,d},{e,f,g,h},{i,j,k,l}} I am looking for a way to manipulate these sublists based on the positions ...
6
votes
1answer
216 views

How can I scale a plot in vector graphic or PDF form?

I am not at all a computer graphics expert, but it seems that portable document format (PDF) files have a "native size," even though they may (and usually do!) contain vector graphics that can be ...
6
votes
2answers
133 views

Evaluate Initialization Cells of another notebook

Although there may be better ways to get data and definitions from another notebook (packages, read/write dumps, ...), sometimes it is convenient to just evaluate the initialization cells from another ...
6
votes
3answers
261 views

AxesLabel in Histogram3D unreadable

I'd like to modify this chart to relocate the z axis label so it's not over printing the values. ...
6
votes
6answers
755 views

How to simplify a complicated Sum in terms of power Sums?

For example, I have: $a=\sum _{r=1}^n x_r \left(\left(\sum _{i=1}^n x_i-x_r\right){}^2-\sum _{i=1}^n x_i^2\right)$ ...
6
votes
3answers
694 views

Ways to compute inner products of tensors

One way to evaluate the following sums is combining Table and Sum: $u_{abcd} = \sum_{e=1}^3 v_{aeb}w_{ced}$ $q_{ab} = \sum_{d,e=1}^3 v_{d e a}w_{deb}$ It will look like ...
6
votes
2answers
254 views

Is it possible to induce Mathematica to chop off parts of Graphics objects that exist outside of a Frame?

I am running Mathematica 7. In a Graphics environment I am setting Frame -> True (and using ...
6
votes
3answers
893 views

Spreading colors in ListDensityPlot

I want to create a two-dimensional plot using data from an external file. This file contains several triplets of numbers. The first two columns indicate the x and y position, while the third one works ...
6
votes
1answer
650 views

How to expand a function into a power series with negative powers?

Is there any way to expand this expression a+b(1-Exp[-T/(b c)]/(z-Exp[-T/ (b c)]) (where a, ...
6
votes
1answer
1k views

Is there an option to change the space/distance between tick labels and axes labels for plots?

In an attempt to squeeze more plots and controls into the limited space for a demo UI, I am trying to remove any extra white spaces I see. I am not sure what options to use to reduce the amount of ...
6
votes
2answers
993 views

How to mark visible points on a Plot3D?

I'd like to illustrate a two-variable function discontinuous at zero. The function is $f(x,y)=xy/(x^2+y^2)$ unless $x=y=0$, in which case $f(0,0)=0$. I thought that I could draw a plot and then mark ...
6
votes
1answer
288 views

Why does Manipulate execute the expression twice?

When I execute Foobar[] in the code below and move a slider, the variable grad is printed twice. Why is this? How can I make the ...
6
votes
1answer
347 views

Want Interactive PlotRange of Graphics[{}]

I am trying to do: ...
6
votes
5answers
277 views

Is it possible to insert arguments into functions when they're used like Function@ or //Function?

Is it possible to insert arguments into functions when they're used like Function@ or //Function? Sometimes I need to do this, but then I have to return to the standard function usage: Function[] ...
6
votes
1answer
1k views

Formatting Ticks and FrameTicks labels with a function

Is there a convenient way to format tick labels? In this example I would like to use the default Mathematica tick intervals, but simply convert the X axis labels to strings with "s" added. As you ...
6
votes
1answer
189 views

LocatorPane, selecting multiple Locators

Consider the following snippet ...
6
votes
1answer
135 views

How to let output and message be print to two separate external files?

How to let output and message be print to two separate external files? Also, I'd like the content print out to have similar look as when it's print inside the notebook, i.e. it should be in ...
6
votes
3answers
2k views

Animate ParametricPlot3D for two different parametric equations

I want to write a computer program to generate 3-D plots (with x-y-t axes) to demonstrate the evolution of the two missiles in the following case: i. $x = 100t$, $y = 80t-16t^2$ for $0\leq t\leq 5$ ...
6
votes
1answer
684 views

How to make a dynamic stopwatch?

For some experiments I need some basic timer function. I tried various methods, and neither of them are fully satisfactory. What I need is a button, that starts/stops a timer, resets timer with each ...
5
votes
1answer
155 views

Why does the order of arguments in Show influence the result?

I am wondering why there is a difference in the results from evaluating the two expressions, which differ only in the order of the arguments given to Show. When I ...
5
votes
2answers
241 views

Understanding Villegas-Gayley

Temporary message: I have written another question about the behaviour the code by Oleksandr R. . Sadly I clicked "discard" and that was lost. I am a bit demotivated now and in order to not let the ...
5
votes
2answers
273 views

How to combine elements of two matrices?

Given two matrices m1 and m2, e.g.: m1 = {{a1, b1}, {c1, d1}} m2 = {{a2, b2}, {c2, d2}} How can one obtain the following? ...
5
votes
3answers
655 views

How to speed up the plot of NIntegrate?

Here is a toy example: f[t_] := NIntegrate[Sin[x], {x, 0, t}]; Plot[f[t], {t, 0, 10}] // Timing Even such a simple example will take 2.8 seconds on my computer. ...
5
votes
7answers
654 views

Defining a function that completes the square given a quadratic polynomial expression

How can I write a function that would complete the square in a quadratic polynomial expression such that, for example, CompleteTheSquare[5 x^2 + 27 x - 5, x] ...
5
votes
2answers
310 views

Variant of the cutting-stock problem in Mathematica

I'm pretty new to Mathematica and am trying to learn to solve problems in a functional way. The problem I was solving was to list the ways in which I could sum elements from a list (with repetitions), ...
5
votes
1answer
565 views

Why does Plot leave gaps in the graph of a continuous function? [duplicate]

I have plotted the overlapping area of the UnitBox and the triangle function as: ...
5
votes
4answers
251 views

Manipulate flickering and consuming lots of CPU

I am new to Mathematica and was experimenting with a simply problem of plotting a tangent to a curve and being able to move the point at which the tangent is drawn using ...
5
votes
1answer
334 views

Label both sides in BarChart

I have labeled the name(A,B,C) of each row on the left and value of each item , is there any way to put the total number(6,7,5) of each row on the right side without changing other labels? ...
5
votes
2answers
268 views

How do I get the equivalent of the $\LaTeX$ \tag{} in Mathematica?

How do I get the equivalent of the $\LaTeX$ \tag{} in Mathematica? $a+b=x \tag{1}$ I'm not necessarily asking how to use the $\LaTeX$ \tag{} itself in ...
5
votes
1answer
165 views

Dialog inside Dynamic Module

The following doesn't appear to work: DynamicModule[{}, Button["Press Me", ChoiceDialog["OK or Cancel?"]]] When I press the button labelled "Press Me", a dialog ...
5
votes
2answers
643 views

Failed to connect remote Mathematica kernel using J/Link

I'm trying to connect to a remote Mathematica 8 kernel (on a Windows machine) using J/Link. On the client machine, I put the JLinkNativeLibrary.dll file in ...
5
votes
1answer
960 views

Combine multiple PDF files into one document

I have multiple single page PDFs I'd like to join together into a single file. (Obviously I mean the file format and not the probability distributions here!) I'm aware of free online services such as ...
5
votes
3answers
204 views

Scope within Context

To define some package-wide functions/variables, what approach is recommended? I tried to use contexts with the Begin function, but this failed: ...
5
votes
2answers
352 views

Cropped pdf file after export

I have plot generated by Plot[] function that I want to export to pdf file. The problem is that Export[] function somehow cuts a ...
5
votes
3answers
222 views

HoldFirst and inserting additional options into a Grid of Graphics

This is related to my earlier question, but is specific to an issue I have encountered with the use of the HoldFirst First, let's create some fake data for ...
5
votes
4answers
3k views

How to get rid of warnings when using Solve on an equation with inexact coefficients?

When I solve this equation in Mathematica 8, I can get the right answer, but with some uncomfortable warnings. Equation: ...

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