# All Questions

1k views

### How to read data file quickly?

I have a tab separated value file with 10 million rows each of which has three tab separated values. The first value is a string, the second an integer, and the third another string. How to read ...
1k views

### Generating graphs interactively (GUI)

I want to create graphs interactively using a GUI. I thought of using a ClickPane[] environment. The code I have (in part borrowed from the Documentation) works ...
679 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 ...
895 views

### An efficient circular arc primitive for Graphics3D

As many people have noted, the 2D graphics primitive Circle doesn't work in a Graphics3D environment. Several solutions to this ...
703 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.
1k views

### Extract current viewing parameters from a 3D view?

Is there a way to find out the current viewing parameters of a 3D view? What often happens is that I create a view, for example: ...
1k views

### Generating evenly spaced points on a curve

In the KnotData package a simple command such as points = Table[KnotData[{3, 1}, "SpaceCurve"][t], {t, 0, 2 Pi, 0.1}]; will ...
1k views

### Efficiently determining if 3D points are within a surface composed of polygons

This is the 2nd part of a previous question which I edited to make into 2 separate questions: Extracting polygons from 3D contour plot surface As an extension of my earlier question involving simple ...
2k views

### Efficient way to generate random points with a predefined lower bound on their pairwise Euclidean distance

Using Mathematica what is an efficient way to generate a list of $n$ random two dimensional points $\{x_i,y_i\}$ where $i=1,...,n$ so that no two points $p_1$ and $p_2$ in the list has an Euclidean ...
611 views

### Programmatically move the cursor to a desired location on the screen

Is it possible to set/move the mouse pointer's location directly from Mathematica without using external tools like Run["xdotool mousemove x y"]?
801 views

### Scale Insetted Characters to Plot

I am trying to place a curly brace within a plot such that the top/bottom of the curly brace line up with two horizontal lines in the plot: I have not been able to find a way to make the curly ...
969 views

### Sort lists according to the order of another

I have three parallel lists (i.e. the elements in position i of each list are related). I want to sort the first list using the function Sort and make the same changes to the other lists so that I ...
3k views

### Changing the background color of a framed plot

I frequently generate framed plots like this: Plot[Sin[x], {x, 0, 2 \[Pi]}, Frame -> True] Is there an easy way to change the background color of the framed ...
1k views

### Fastest way to calculate matrix of pairwise distances

It is a very common problem that given a distance function $d(p_1,p_2)$ and a set of points pts, we need to construct a matrix ...
2k views

### Plotting a set of trajectories (not a vector field) in 3D

Consider a set of trajectories in 3D space, that possibly converge. By visualizing trajectories as arrows the result will look crowded as each arrowhead will be placed where the attractor is. In 2D, ...
903 views

### How to speed up the function DelaunayTriangulation?

First define a function meshGrid to generate some points: ...
1k views

### Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$

Looks like a question for pupils, right? In fact if the available math symbol is limited to $+$, $-$, $\times$, $/$ then it's easy to solve: ...
3k views

### About multi-root search in Mathematica for transcendental equations

I have some questions for multiroot search for transcendental equations. Is there any clever solution to find all the roots for a transcendental equation in a specific range? Perhaps ...
430 views

### Why does Simplify ignore an assumption?

Here is the example: Simplify[x + y, x + y == a] Simplify[x + y, x + y == 5] Mathematica 9 output: x+y 5 I expect the ...
521 views

### How to get the real PlotRange using AbsoluteOptions?

The problem in general involves the unreliable behaviour of AbsoluteOptions when option values are implicitly specified (e.g. ...
1k views

### Vertically aligning two separate plots

How do I vertically align plots so that the two plots are displayed in a way that lines up with respect to the axes? The code I have so far is: ...
419 views

### Implementing a safe ValueQ that does not evaluate its argument

Mathematica has a built-in function ValueQ. Quoting the docs, ValueQ[expr] gives True if ...
731 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 ...
760 views

### Extracting the coordinate of a particular point of interest from a ListPlot

Is there a way to obtain the coordinate of a point of interest in a ListPlot? As an example, I have a list containing many sets of 2D coordinates and the plot ...
519 views

### Question about designing a particular data structure

Background: I store polygons with a color assigned at the face level. In some occasions I want to use vertex colors but I want to store data efficiently, i.e. don't want to duplicate data to the ...
1k views

### I'd like to display field lines for a point charge in 3 dimensions

I'd like to display field lines for a point charge in 3 dimensions. Not a force field (short arrows) but continuous field lines that start on the charge.
2k views

### Is it possible to prerender animation in Wolfram Mathematica?

I have a DensityPlot which is evaluated for a long time. I wish to use it with animation, but it is absolutely inapropriate. Is it possible to render animation ...
1k views

### Real Size Image Printing

I am generating a complicated graphics with Mathematica, but with objects of given sizes (e.g. a line of length 1 inch, between two points). I want to make sure that when I export the graphics, e.g. ...
455 views

### How can I conveniently call igraph through RLink?

Mathematica has lots of functions for working with graphs, but this functionality is not yet as mature as the igraph library. It is useful to have access to igraph from Mathematica, both for ...
306 views

### Custom functions by delegating options in a specific way and using core functions

I'd like to create a custom function that does essentially the same as a core function of mathematica but uses different default settings. Example: I want a Plot function that uses Mathematica's core ...
2k views

### More on combining 2d and 3d plots

This is a spin off/follow up to Can 2D and 3D plots be combined so that the 2D plot is the bottom surface of the 3D plot boundary? ... Following Sjoerd's method, I did this: ...
738 views

### Block attributes of Equal

I answered “Equating matrices (or higher order tensors) element-wise” with: ...
328 views

### Using several anonymous functions mixed together

This works: list // BarChart[#[[2]], ChartLabels -> DateString @@@ #[[1]], ChartStyle -> "Pastel"] & This doesn't: ...
483 views

### Sort+Union on a list

Probably this is too trivial question for this forum but for some reason I am not getting it on my Mathematica 7 so far. I have a list ...
373 views

### Scoping in assigning a derivative

While answering another question, I stumbled upon a problem I cannot easily resolve. To assign the derivative of a function to another function, typically one can do this with a ...
572 views

### How to make traditional output for derivatives

Hello again after some pause. i have a problem how to present partial derivatives in traditional form, not as Mathematica gave it to me in its notation. So I want to present this ...
4k views

### Flipping axis on a plot

I want to make a 2D plot where the x-axis is flipped so the higher numbers are on the right and lower numbers are on the left. I've managed to do it by flipping the data and making new ...
789 views

### How do you check if there are any equal arguments(even sublist) in a list?

I would like to set up a function which has to return True if at least two arguments of a given List are equal. So if I give {1,4,6,2} to the function it has to ...
1k 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 ...
263 views

### Copying one symbol into another

I would like to know how can I completely copy one Symbol to another. When I say copy, a refer to UpValues, DownValues, ...
1k views

### Find continuous sequences inside a list

I have a list which is something like this: {3,4,5,6,7,10,11,12,15,16,17,19,20,21,22,23,24,42,43,44,45,46} What I'd like to to is get the intervals which are in ...
1k views

### How does Mathematica integrate?

Basically, this question can be considered to be an extenstion to my other question. What I wanted to do was this integral as homework (it is indefinite BTW so no approximations using Simpson's Rule ...
1k views

### How to change the style definitions for Default.nb?

I have looked over other questions related to style definitions, and looked through the Mathematica 8 documentation, but I do not know why I am having so much difficulty setting the default font in my ...
649 views

### PolarPlot render oddities

I apologize if this is a obvious question and answer, I don't often use Mathematica to display plots or graphics in general to be honest. So, I was tutoring my cousin yesterday in relation to Polar ...
626 views

### Transparent textures don't show

EDIT For now, I'm going to accept Brett's answer. It's a way to get transparency back by having 3D calculations done in software instead of hardware. It addresses the symptoms but not the ...
2k views

### Plotting piecewise function with distinct colors in each section

I have a piecewise function that I would like to plot but I was wondering if it is possible that each part of the function that is plotted when its corresponding condition is true be plotted with a ...
618 views

### Efficient way to combine SparseArray objects?

I have several SparseArray objects, say sa11, sa12, sa21, sa22, which I would like to combine into the equivalent of {{sa11, sa12}, {sa21, sa22}}. As an example, I ...
2k views

### How to Delete Elements from List1 appearing in List2?

I'm new to functional programming of Mathematica and trying to remove one list of assorted elements from another. However I only find functions working with the Index rather than the values itself: ...
1k views

### How to use FindFit to fit an implicit function?

Now I am trying to fit some data with a implicit model function. Firstly, I tried a toy example. Toy example with input and output ...
902 views

### First positive root

Simple question but problem with NSolve. I need help how to extract first positive root? For example: ...

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