# All Questions

1k views

### First positive root

Simple question but problem with NSolve. I need help how to extract first positive root? For example: ...
3k views

### Can Reduce *really* not solve for x here?

Sometimes I get the feeling I'm just flailing blindly with Mathematica. Is solving for $x$ in the equation $$\frac{\cosh (x/2)}{x} = \sqrt{2}$$ really beyond the scope of Mathematica? I try to ...
2k views

### extract values from replacement list

Solve returns a list of replacement rules In: Solve[x + y == 3 && x - y == 6, {x, y}] Out: {{x -> 9/2, y -> -(3/2)}} I am only interested in the ...
8k views

### Creating a table/Matrix during a For loop

I have a For loop (with i as a counter), which calculates different values (y1, ...
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 ...
377 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 ...
1k views

### Combined numerical minimization and maximization

I want to numerically calculate the maximum of a function defined by the minimization of another function, like the following: ...
776 views

### Automatically load packages at startup

I'm a physics student and I try to simplify my day with Mathematica. Every time I use Mathematica I need Div[], Grad[], ...
2k views

### The difference between 0. and 0

I have a function for which 0 is a special case: f[A___, 0, B___] := 0 But since I am doing numerics, sometimes in the course ...
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 ...
10k views

### $\LaTeX$ and Mathematica

I quite often would like to draw graphics in my $\LaTeX$ documents using Mathematica. I have encountered three problems. I would like to know if there are any workarounds to these problems I would ...
1k 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?
1k 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 ...
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 F and G F[x_] := x + 2 G[x_] := x And I want ...
3k views

### How to find circular objects in an image?

How could I use morphological processing to find circular objects in an image? More specifically, I need to detect road signs. I need to get the "80 speed limit" sign from this image:
911 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.
668 views

### Placement of Condition /; expressions

It is my practice to place Condition expressions on the left side of := and :> in almost ...
4k 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 ...
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 ...
977 views

### What tools can help in realizing tail recursion?

I had nice discussions with Leonid and Rojo that got me interested in tail recursion. Tail recursion is not always easy to realize with Mathematica, so it would be nice to have some tools to help with ...
1k views

### “Covering up” text in Graphics

Consider the following code: ...
758 views

### Can a function be made to accept a variable amount of inputs?

I have a function that takes two inputs and processes them for a single output. What I need is one that can take a varying number of inputs. and process them to a single output. Is this possible in ...
8k views

### Is it possible to export the equations from Mathematica to MATLAB?

Is it possible to export the output expressions from Mathematica computations (e.g., equations) in valid MATLAB syntax?
3k views

### Given a Table of Plots with some parameter, how would I mark each of the plots with that parameter

I've got a two variable function that I'm plotting against one axis for a few different values of a parameter ...
628 views

### How do you set attributes on SubValues?

SubValues, as discussed in a previous question, are declared as follows ...
3k views

### How to create a heatmap from list of coordinates?

I have a list of coordinates in form {{x1,y1},{x2,y2},...} Is there a way in mma to builds density plots based on position ( ...
563 views

### How do I obtain an intersection of two or more list of lists conditioned on the first element of each sub-list?

Given two lists like list1 = {{1, 1}, {2, 4}, {3, 9}, {4, 16}}; list2 = {{2, 6}, {3, 9}, {4, 12}, {5, 15}}; I would like to produce an output like ...
530 views

### Returning an unevaluated expression with values substituted in

Let's say I have a function formula[x_List] := (x[[1]] - x[[2]]) + (x[[3]] - x[[4]]); and I want to pass it a variable and get back the unevaluated formula with ...
404 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 ...
3k views

### What does # mean in Mathematica?

I asked Mathematica to compute the following Solve[c (1-x)^2-x^(1/4) == 0, x] and it returned this: x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 ...
2k views

### About the number format in ticks

I want to LogPlot a function, but I have the trouble in the number format in the ticks. For example, ...
959 views

### How do I perform string matching and replacements?

What are, and how do I use Mathematica's string matching and replacement tools?
749 views

### How to extract the numerical value of a dynamical variable

I want to inspect interactively an image by selecting points by the mouse pointer. This is easily done by LocatorPane - here is a simplified example: ...
1k views

### RevolutionPlot3D: but NOT revolving about the z axis

I want to demonstrate generating a solid of revolution by revolving a planar region about, say, a horizontal axis. However, RevolutionPlot3D doesn't seem to have an ...
1k views

### Select/Delete with Sublist elements?

Probably easy and short question, I still didn't fully figure out how to easily select/delete sublists from a list. Example: tt = {{2, 4}, {4, 8}} I want to delete/select all the elements where ...
2k views

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974 views

### How Can I use Solve/Reduce Output

Suppose I want x and y to be rationals Solve[ x^2 + y^2 == 1, {x, y}, Rationals] I am ...
261 views

In the ideas shared in my answer to this post Struct equivalent in Mathematica? at the end I propose a solution that changes the way Set works in a particular case that can be expressed in plain words ...
628 views

### Solve an equation in $\mathbb{R}^+$

How can I solve this equation (both numerically and literally) only in the positive reals $\mathbb{R}^+$? Solve[x == (v0 - (A CD t v0^2 ρ)/(4m)) Cos[θ] t, t] And ...
2k views

### Fixed color scale in multiple density plots

I think there should be a simple solution for my current problem, but neither StackOverflow (or the help of Mathematica) or Google have it. I have to plot multiple density plots with a color ...
525 views

### Evaluating an If condition to yield True/False

I would like to decide whether an option passed to my custom function has the value Automatic or something else. This is my attempt: ...
342 views

### Help on evaluation control?

I want to plot series of slopes: x, 2x, 3x, 4x, 5x, 6x... I'm trying to do this: ...
237 views

I don't understand the following: f[a_, b_] := a + b ls = {1, 2, 3}; MapThread[f, {ls, {10, 20, 30}}] This yields ( as expected ) {11,22,33} If I change ...
7k views

### Resources for beautiful Mathematica Stylesheets

When the Wolfram Demonstrations were introduced and the Documentation-Center was redesigned, I remember it was the first time I thought someone had put some effort into creating a beautiful ...
1k views

### Syntax highlighting for your own functions

Mathematica has a useful feature that for functions and special constructs getting passed local variables (for example Minimize or ...
4k views

### 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. ...
3k views

### 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 ...
4k views

### How can I extract data points from a black and white image?

Consider the following graph (source): Is there any way to extract the data points from this image in a semi-automatic way? I have seen, and tried the methods suggested in this question, but they ...