# All Questions

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### Torn edge paper effect for images

In my answers to Plotting Error Bars on a Log Scale I used a so called "torn edge" effect from on one of the images. @SjoerdC.deVries commented: "BTW I liked the ripped-out look of your InputForm ...
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### Is it possible to improve Mathematica's auto-completion feature?

In this answer Brett Champion describes how one can intercept and modify the suggestions used for auto-completion. Question: Is it possible to modify the suggestion for the automatic auto-completion ...
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### How can this confetti code be improved to include shadows and gravity?

Here's some confetti: ...
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### How to check if a 2D point is in a polygon?

Background: I use code from An Efficient Test For A Point To Be In A Convex Polygon Wolfram Demonstration to check if a point ( mouse pointer ) is in a ( convex ) polygon. Clearly this code fails for ...
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### What does the construct f[x_] := f[x] = … mean?

This question mentions "x := x = trickery". What does defining a function as f[x_] := f[x] = ... do and what is it good for?
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### How can I generate this “domain coloring” plot?

I found this plot on Wikipedia: Domain coloring of $\sin(z)$ over $(-\pi,\pi)$ on $x$ and $y$ axes. Brightness indicates absolute magnitude, saturation represents imaginary and real magnitude. ...
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### How to create new “person curve”?

Wolfram|Alpha has a whole collection¹ of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica ...
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### Extract values for ViewMatrix from a Graphics3D

Under More Information in the help page of ViewMatrix the following entry can be found With the setting ...
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### Understanding CDF

Update Since more and more issues are revealed as I venture deeper into the world of CDF, I decided to make this thread more general and hopefully more useful. I know posted my findings as an answer, ...
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### Implementing a first person view of 3D objects in a scene

I've created the following scene with a Chinese-style building surrounded by trees, and a horse and a rabbit grazing on the grass in Mathematica (don't ask me why there's a bust of Beethoven in ...
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### Is it possible to customize the Suggestions Bar?

I'd like to be able to customize the Suggestions Bar in v9.0 to provide recommendations of my own. Possible example: when doing unit calculations, I'd like it to suggest converting the answer to ...
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### Creating legends for plots with multiple lines?

So I have a graph with multiple lists, for e.g. data = {{1,2}, {3,4}, {3,5}, {2,3} . . .} If I then do ...
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### Functions vs. patterns

Every time I define a new function, I wonder which construct I should use: true functions obtained by using Function, or rule-based syntax. For example, these are ...
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### How to make a 3D globe?

There are many ways to create a 3D Earth that is rotatable (see here, here, related here), but most of them have some drawbacks. These issues mainly stem from either ...
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### How can I use Mathematica's graph functions to cheat at Boggle?

This question is inspired by a Stack Overflow question that I decided to solve using Mathematica. In addition to Mathematica, I thought I'd use some of the new version's graph-related functionality, ...
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### What is the most convenient way to read definitions of in-memory symbols when we don't have the source files? (Spelunking tools)

Note: I put Simon's implementation on GitHub. Contributions welcome! When trying to read the definition of already defined (package or built-in) symbols using ...
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### How can I calculate a jigsaw puzzle cut path?

I want to generate a path to cut an arbitrary shape into a set of jigsaw puzzle pieces. All pieces must be unique to preclude placing a piece in the wrong spot. Pieces must be interlocking such that ...
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### Profiling from Mathematica

I've always wished I could do some profiling like you get in Wolfram Workbench, but directly from Mathematica, without using or having Workbench. If it is possible, how can I do it?
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### Measuring fractal dimension of natural objects from digital images

This is a useful topic. A college physics lab, medical diagnostics, urban growth, etc. - there is a lot of applications. On this site by Paul Bourke about Google Earth fractals we can get a high ...
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### Changing color of an object in an image

Consider the following image: How can I change all red colors in this image into (for example) blue.
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### Speeding up this fractal-generating code

I used the code below (which is a sample from this gist containing more similar code) in my answer to my own question about Mandelbrot-like sets for functions other than the simple quadratic on ...
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### What is the difference between Reduce and Solve?

Solve and Reduce both can be used for solving equations. Just by working with them, I know there are some differences between ...
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### What are the best practices / most common / idiomatic ways to report errors in Mathematica?

In particular, what are the best ways to report errors about incorrect arguments to a function? Checking for the correct arguments is relatively easy using patterns, but how to report an informative ...
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### Image segmentation and object separation in 3D using Mathematica

I currently work on an image segmentation scenario to detect cell nuclei in 3D using Mathematica. The data I have are image stacks in the TIFF file format. I would like to keep the sequence of image ...
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### Is Mathematica an Implementation of the Wolfram Language?

I am trying to figure out what the announcement of the Wolfram Language means for Mathematica. Is Mathematica an implementation of the Wolfram Language, or is it something else?
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### Using a PatternTest versus a Condition for pattern matching

My last question to the site resulted in several answers that involve using pattern matching in Mathematica, a feature I wasn't very familiar with at the time. I am currently reading Mathematica ...
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### How to show solid bodies using volumetric rendering?

Note: This question was asked when Mathematica 8 was latest release. Version 9 has built-in support for volume rendering through Image3D. There's an example on ...
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### How to generally match, unify and merge patterns?

This question was split from this one. While that question is now about how to match two particular patterns (mostly using Verbatim or ...
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### Updating Wagon's FindAllCrossings2D[] function

Stan Wagon's Mathematica in Action (second edition; I haven't read the third edition and I'm hoping to eventually see it), demonstrates a nifty function called ...
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### Vary the thickness of a plotted function

I know, that I can change the color of a function with the help of PlotStyle: Plot[Sin[x], {x, 0, 3 Pi}, PlotStyle -> {Green, Thickness[0.01]}] I also know, ...
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### What is a Mathematica packed array?

A simple sounding question with a few sub questions: What is the difference between unpacked vs packed array? Are packed arrays more space efficent, how much so? Are packed arrays more time ...
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### InternalBag inside Compile

Since InternalBag, InternalStuffBag and InternalBagPart can be compiled down, it is a ...
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### When I can assume that all decimal digits returned by Mathematica are provably correct?

How to Control the Precision and Accuracy of Numerical Results Arbitrary-Precision Numbers Mathematica works with exact numbers and with two different types of approximate numbers: ...
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### Animating mathematica.se logo

As we all know our site's logo was completely generated by Mathematica. I suppose it is quite natural to make the next step -- to generate the animated version of this logo. There's a lot of space for ...
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### Does Mathematica have advanced indexing?

I have two $M \times K$ arrays $L, T$ where I would like to set all the elements in $L$ to zero whenever the corresponding element of $T$ is greater than 15. The ...
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### Having used Mathematica as a “gateway” language, where to from here?

I have been using Mathematica for about a year. It is the first language that I have attempted to learn. I'm still very much a newbie, but there are moments I feel more like I am waving than drowning. ...
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### Automatic e-mail/text message when a calculation has finished?

Sometimes Mathematica takes quite a while to finish calculations and it would be convenient to be able to move away from the computer while it is working. I was wondering if there is any "clever" hack ...
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### The clearest way to represent Mathematica's evaluation sequence

WReach has presented here a nice way to represent the Mathematica's evaluation sequence using OpenerView. It is much more clear way to go than using the standard ...
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I have been working on picking expressions apart using Head and Part and encountered a little mystery. Consider the canonical ...
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### How to “Copy as Unicode” from a Notebook?

I spent some time manually editing a post replacing Mathematica ASCII \[Alpha] with Unicode α. I did this by laboriously ...
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### My donut has holes in it!

More than one hole, I mean… I’m trying to export from Mathematica into the X3D format, with the longer term goal of generating 3D figures for PDF inclusion. But I'm stuck at the first step: ...
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### Detecting grid lines in a raster image

Motivation: Last October 7 there was a presidential election in Venezuela. Although the opposition saw an unprecedented increase in its votes, the government votes increased even more resulting in the ...
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### How can this image (optical illusion) be created with Mathematica?

I came across this image the other day: and liked the sensation of it pulsing. I was wondering if anyone would know how to create something similar with Mathematica (without the Pink Floyd Dark ...
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### Creating ghost trail effects

Does anyone know how to create a ghost trail effect? For a simple example look at this screenshot: You can find the actual animation here. What I would ultimately like to see it happen is to make ...
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### Can Mathematica propose an exact value based on an approximate one?

Sometimes, I use Mathematica to do some hypothesis on homeworks to make the question easier. For instance, when I have to compute big sums when $n\to\infty$ and Mathematica can't give the exact ...
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### How can I create a function with optional arguments and options?

Is it possible to create a function with optional arguments that also takes options? Here is a simple example. I have a function f with option "g". It also has ...
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### How do I plot coordinates (latitude and longitude pairs) on a geographic map?

I'm attempting for the first time to create a map within Mathematica. In particular, I would like to take an output of points and plot them according to their lat/long values over a geographic map. I ...
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### Reconstruct text pages cut by shredder

Q1: I have a page of printed text file, but it was cut by a paper shredder (from top to bottom). You can download all the paper fragment here. There are some examples of them. How can I reconstruct ...