25
votes
3answers
895 views

Common subexpression from two expressions

I am working with some unpleasantly tedious polynomials, which need to be manipulated in various ways (integrate with respect to some variable, differentiate with respect to another). Since these ...
12
votes
3answers
489 views

Why do buttons with ChoiceDialog freeze the front end?

Pressing the button below will freeze my front end. An unpainted white dialog box comes up, then it completely freezes, and I need to forcibly kill the front end. CPU usage stays at zero during ...
9
votes
1answer
325 views

Confused by (apparent) inconsistent precision

$$ e^{\pi \sqrt{163}} \approx 262537412640768743.99999999999925 $$ E^(Pi Sqrt[163.0]) N[E^(Pi Sqrt[163.0]), 35] NumberForm[E^(Pi Sqrt[163.]), 35] returns ...
58
votes
1answer
2k views

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?
57
votes
6answers
9k views
58
votes
4answers
2k views
64
votes
3answers
2k views

Automatically generating a dependency graph of an arbitrary Mathematica function?

Has anyone written a function to pull the function dependencies of a function? That is, it would be nice to have a function that returns a list of function dependencies as a set of rules, terminating ...
29
votes
4answers
3k views

How can I make an X-Y scatter plot with histograms next to the X-Y axes?

I just saw a nice plot there: How could I implement that in Mathematica — by which I mean the plot structure, not so much the styling.
47
votes
1answer
1k views

Incompatible Changes since Mathematica Version 7?

There is documentation of the incompatible changes made to Mathematica with each major release: Incompatible Changes since Mathematica Version 1 Unfortunately that documentation simply stopped ...
26
votes
5answers
1k views

What is the complete list of valid Front End Tokens?

What is the complete list of valid Front End Tokens? Preferably, by version number. Keywords: FrontEndToken, ...
29
votes
6answers
2k views

Extruding along a path

I'm trying to render a 3D image of a path by extruding a circular cross-section along the path, creating a "snake-like" path. Here is an image I found to illustrate: I can't seem to figure out if ...
28
votes
2answers
996 views

Can a Trie be implemented efficiently?

What is the most space and time efficient way to implement a Trie in Mathematica? Will it be practically faster than what is natively available in appropriate cases?
23
votes
5answers
2k views

Partition a set into subsets of size $k$

Given a set $\{a_1,a_2,\dots,a_{lk}\}$ and a positive integer $l$, how can I find all the partitions which includes subsets of size $l$ in Mathematica? For instance, given ...
22
votes
4answers
840 views

Resource management in Mathematica

I am using a library that has functions like createSomeObject[] and deleteSomeObject[obj]. It is an interface to a C language ...
23
votes
3answers
1k views

How to load a package without naming conflicts?

This question applies to any package, but I encountered this problem while working with graphs. There are symbols in the Combinatorica package (such as ...
20
votes
5answers
1k views

How to splice together several instances of InterpolatingFunction?

I have a set of InterpolatingFunction returned by NDSolve which are valid over different (but overall continuous) domains. How ...
19
votes
2answers
717 views

How to inject an evaluated expression into a held expression? [duplicate]

I know that there are methods to structurally manipulate held expressions (discussed e.g. here), but I failed to apply those for this particular problem: ...
23
votes
3answers
2k views

Reading periodic elements from a large file

I have a large binary data file (big endian) with 100+ million "rows" of 11 elements, combination of floats and integers. This is the format: ...
21
votes
1answer
524 views

Shorter syntax for Fold and FoldList?

I find it tedious to write out the following: a = {1, 2, 3, 4}; Fold[f, First @ a, Rest @ a] f[f[f[1, 2], 3], 4] It ...
28
votes
2answers
1k views

How does Plot work?

I considered the following function: sin[x_] := Module[{}, Print["x=", x]; Sin[x] ] in Mathematica. Next, I tried to plot it using: ...
19
votes
5answers
2k views

How to pass a symbol name to a function with any of the Hold attributes?

Given a function with the attribute HoldFirst, HoldAll or similar, and a variable, list, how ...
15
votes
2answers
1k views

How do I automatically evaluate a cell when a notebook is opened?

I'm trying to put together a GUI in Mathematica and need to evaluate one cell to kick that off. Is there a way to automatically evaluate that cell when the notebook is opened? Here is an example of ...
18
votes
3answers
1k views

Removing unwanted appearance of underlying mesh

Let us first define two positive definite matrices: M1 = {{2, -6}, {4, 8}}; M2 = {{2, 3}, {4, 8}}; then set two points ...
17
votes
5answers
2k views

Having the derivative be an operator

How do I create an operator which acts like a derivative to everything to the right of it: for example: $ \left( \partial_x + \partial_y + z \right ) x \psi $ How do I make that evaluate to: $x ...
6
votes
5answers
1k views

sliding a tangent line along a curve

I am confused by Dynamic. I am trying to slide a tangent line along a curve, without using DynamicModule, so that I can include ...
27
votes
2answers
1k views

Meaning of backtick in floating-point literal

If I compute, say, 1/3//N, Mathematica displays 0.333333 as the result. When I copy that output to use elsewhere, the paste ...
13
votes
1answer
1k views

Plot showing discontinuity where it shouldn't

I was trying to integrate a continuous function with a kink and I did it two ways and both ways the plot of the result shows a discontinuity. I also later want to differentiate the Integrated ...
15
votes
1answer
499 views

Using Evaluate and Evaluated -> True in Plot

A few use cases: (1) This, as expected, returns (almost) immediately: f[x_?NumericQ] := Evaluate[(Pause[1]; x)] Plot[f[x], {x, 0, 1}] (2) This takes ...
8
votes
2answers
1k views

Create complicated text formulas in graphics

I want to put somewhat complicated, or at least non-standardly formatted, text on some of my graphics. For example, I'd like to be able to use f^[4](x) (where the ...
476
votes
6answers
163k views

xkcd-style graphs

I received an email to which I wanted to respond with a xkcd-style graph, but I couldn't manage it. Everything I drew looked perfect, and I don't have enough command over ...
54
votes
3answers
4k views

Metaprogramming in Mathematica

Being functional, and having no "quotation", i.e. essentially treating data and programs semantically same, Mathematica seems naturally capable of doing metaprogramming. But could anyone construct a ...
47
votes
1answer
2k views

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 ...
40
votes
4answers
5k views

How to change the default ColorData used in Mathematica's Plot?

This question leads on from the recent question What are the standard colors for plots in Mathematica? There it was determined that the default color palette used by ...
35
votes
4answers
1k views

Compiling more functions that don't call MainEvaluate

I would like to use Compile with functions defined outside Compile. For example if I have the two basic functions ...
34
votes
6answers
2k views

How to plot ternary density plots?

How can I get a ternary density plot just like the plots from OriginLab? ContourPlot and DensityPlot seemingly can accept the ...
46
votes
3answers
1k views

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 ...
37
votes
3answers
2k views

How to distribute proprietary Mathematica code

If I want to make package-code completely unreadable, in a way that the end-user can only call my functions, but has no way to re-engineer my definitions, how would I do that? I know I can use ...
36
votes
6answers
1k views

Items known by CurrentValue

CurrentValue can be used to poll the state of numerous system values such as the mouse position. Its help page doesn't list all possible items, though. An item like ...
33
votes
3answers
797 views

Are there guidelines for avoiding the unpacking of a packed array?

Packed arrays are very useful because they save memory and generally allow speedier and more efficient calculation times. If a list of data currently stored as a packed array is unpacked, it can slow ...
36
votes
2answers
949 views

Why is the new PositionIndex horribly slow?

This issue has largely been mitigated in 10.0.1. New timings for the final test below are: ...
30
votes
12answers
2k views

Map a function across a list conditionally

It seems that this is a really basic question, and I feel that the answer should be obvious to me. However, I am not seeing. Can you please help me? Thanks. Suppose I have a list of data ...
19
votes
2answers
6k views

How to calculate contour integrals with Mathematica?

How to calculate the integral of $\frac{1}{\sqrt{4 z^2 + 4 z + 3}}$ over the unit circle counterclockwise for each branch of the integrand?
37
votes
5answers
761 views

Placement of Condition /; expressions

It is my practice to place Condition expressions on the left side of := and :> in almost ...
27
votes
6answers
2k views

How to select minimal subsets?

I am a newbie, so please point me in the right direction if you feel this question has been answered somewhere else before. Here goes: Suppose I have a list like this: ...
33
votes
4answers
2k views

Aborting evaluation when the memory exceeds a certain limit

Sometimes when generating a lot of data the memory usage shoots beyond its physical realm and my laptop freezes. There is no way to stop Mathematica when this happens. Task manager (or its equivalent ...
28
votes
4answers
6k views

Density plot on the surface of sphere

I would like to make density plots of a list of (size 2 or 3) spherical harmonics on the surface of a sphere. I'd like to plot it so that each element of that list is using a different color (red ...
26
votes
6answers
584 views

Constructing symbol definitions for With

I would like to be able to define two arrays, one containing symbol names and one containing the values of those symbols, for use in constructs such as With. For ...
21
votes
4answers
1k views

How to collect result continuously (interruptible calculation) when running parallel calculations?

This is the most common pattern to compute a table of results: Table[function[p], {p, parameters}] (regardless of how it's implemented, it could be a ...
24
votes
3answers
632 views

How to flush machine underflows to zero and prevent conversion to arbitrary precision?

I'm working on some pretty intense computation in Mathematica; when my code started running slowly, I tracked the source of the problem to Exp[]. I need to ...
20
votes
5answers
972 views

How do you programatically load data into symbols?

I am trying to convert a list of string names into symbols, which will then be used to store data. I have 24 files (where the name of each file is a member of the list mentioned above) that I need to ...

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