# All Questions

26k views

### What are the most common pitfalls awaiting new users?

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...
13 views

### How to show user-defined level set when using ListContourPlot3D [on hold]

I want to display the level sets of a 3D point data.(e.g. data values equal 2 and 4 respectively) The provided examples of RegionFunction option for ...
269 views

### Why does a comma insert a line break in a comment?

I like to include capital letters and punctuation in my comments. But when I put a comma into a Mathematica comment of the (* ... *) type, it usually causes the comment line to break, with a new line ...
26 views

### I need help with Bifurcation curve in a RQ parametric space [on hold]

I am doing a Spruce Budworm analysis and trying to make a diagram of the bifurcation. The original equation, after applying dimensionless quantities, reads, ...
330 views
+100

### Adapting “Find and Replace” functionality to work with Patterns

I was thinking if there is something like Find and Replace (Crtl+F) functionality adapted to work with patterns. Probably not, but it seems possible to create this with some effort and skills in ...
58 views

### Eigen energies of 2D time independent Schrödinger equation

Firstly, I am aware that a similar question of this type was asked, but it was not helpful as it was only one dimensional (so please don't mark my question as a duplicate) The trouble I am having is ...
166 views

### Saving a source file adds (* ::Package:: *) to the first line

I am running Mathematica 9 on a linux machine and I've encountered the following behaviour that I am trying to understand. When I'm editing multiple source (.m) files using mathematica saving adds a ...
255 views

### How to draw multi curves in a graph with errorbars

The curves are composed by several 2*n nested lists. I want these curves be placed in a 3d way, like the xy plane is for the data, different curves are located in several parallel xy planes with ...
83 views

### Using Runge-Kutta method to find arc length [duplicate]

I don't know much about using the Runge-Kutta method in Mathematica, so I have to ask a straightforward question: How can I use Runge-Kutta to numerically approximate the parameter t of this curve in ...
39 views

### Solve on parametric equation produces inequal results

I have a parametric (parameter t) equation in two dimensions (vectors). s = Solve[pt[t] == qt[t], {a, b}] Both pt and qt are parametric lines using a and b as ...
41 views

### Can association be used to find the maximum key less than a specific number?

Suppose we have an association assoc. assoc = <| 1 -> 1, 3 -> 2, 5 -> 3, 7 -> 4, 20 -> 5|>; Instead of ...
23 views

### Error Exporting STL --insufficient elements to export

I am trying to export the following code as an STL file: ...
53 views

### Series with a specified number of terms

I'm doing calculations with Series where I don't know the power of the leading order term. I would like to keep a specified number of terms, but since I don't know the leading order this is proving ...
582 views

### How to identify chemical substance from tattoo?

A friend of mine made a tattoo on his chest of some chemical substance formula. He challenged us to identify which substance is that. I thought that perhaps a combination of: Mathematica image ...
984 views

### How to plot Error Bars in a 3D scatter plot

This is a simple problem which is proving difficult to solve. I want to plot error bars on points in a 3D scatter graph. I plot error bars on points within a 2D scatter by: ...
31 views

### ListLogLinearPlot with Legends

I need to plot this data in Log scale for both axes, and also need to add a legend. But since they are joined dots, the legend that appears is just a dot instead the plotstyle I choose. ...
2k views

### How to save all data in all variables so that loading it is fast?

I've got this CSV file I've imported that has tens of millions of lines in it. It takes around 20 minutes to import. I've been working with it for a while and have the processed data spread out in a ...
20 views

### Generating a list consisting of function values like in a triangular matrix

A goal is to generate a SymmetrizedArray of dimension n^k with specified symmetry (let it to be ...
70 views

### Unnecessary free space under the figure

Here is the data ...
87 views

### MinMax function (Mathematica v10.1.0) conflicts with NDSolveFEMMinMax?

Some problem in v10.1.0 (Windows 8.1 x64) and the new MinMax... ...
132 views

### How to plot the graph of the equation F[x,y]=0 if y is real number, x is complex? [on hold]

I have an equation F(x,y;a,b,c,...)=0, where x and y are variables, a,b,c,... - parameters. y is a real number, x - complex. For every given y I need to solve this equation, i.e. to find Im(x) and ...
530 views

### Multiple notebooks in Mathematica

While working with multiple files in Mathematica, is there a way to have the names of the files appear along with the minimized window of the file. I mean that sometimes I forget which file was places ...
2k views

### Character edge finding

The following line of code finds the edge of a character: ...
68 views

### SetOptions for CoordinatesToolOptions for DateListPlot?

DateListPlot does not respect my Options setting for CoordinatesToolOptions: ...
359 views

### Most efficient way of making pair list from a list

I have a bunch of datasets which looks like: 3 7 1 6 5 8 2 4 1 2 8 1 5 2 5 ... and I need to make a list of pairs such that the first element makes a pair with ...
69 views

### Plotting points on the horizontal line

I have list such as list = {1, 5, 2, 6, 3,...} and I need to plot the numbers from the list on a horizontal line such that there will be on a place on horizontal ...
34 views

### Create a random 2x2 matrix with a repeated eigenvalue and single eigenvecor

Does anyone have a good technique for creating a random $2\times 2$ matrix that has one eigenvalue of multiplicity two, but only a single eigenvector? And more generally, has anyone written a ...
70 views

### Is Sow/Reap compatible with Composition?

I'm trying to figure out why these two pieces of code return different results. As expected, f[Reap[Sow[x]]] gives ...
105 views

### Issue in NDSolve and unknown error

I try to solve a simple BVP: $A {v}''(t)+B v(t)=f(t)$ where $A, B$ — $5\times 5$ matrices, $f(t)$ — 5-dimentional vector-function with the use of NDSolve. Each component of $f(t)$ is a combination ...
24 views

### Export PDF margins different in V9 & V10 compared with version 7

PDFs in version 9 and 10 have bigger margins than in version 7. I can't find any differences in the settings. I'm using A4 paper and it looks like version 9 might be trying to use letter size. ...
19 views

### Controlling scaling of multiple vector fields in VectorPlot3D

I'm trying to plot the electric and magnetic fields of a relativistically moving electric charge using VectorPlot3D, and apply "Manipulate" to change the velocity. The code I'm using is as follows: ...
56 views

### Approaches to solving non-linear systems of equation with assumptions

The specific type of system looks as follows: \begin{align} (r-r')x+4d_1 x^3+4d_{12}xy^2 &= 0 \\ (r+r')y+4d_2 y^3+4d_{12}yx^2 &= 0 \\ \end{align} Where $r,r',d_1, d_2, d_{12}$ are all real ...
99 views

I would like to solve numerically the following PDE: $$\frac{\partial}{\partial t} p(x,t)=-\frac{\partial}{\partial x}p(x,t)+\frac{1}{2}\frac{\partial^2}{\partial x^2}[x^2\,p(x,t)],\;x\ge0,\;t\ge0, ... 0answers 29 views ### Problems with my units? [duplicate] I have my own unit is called "Euros" Input:5 Euros -3 Euros Output:2 Euros Input:5 Euros - 5 Euros Output:0 How can I make to get 0 Euros? Output: 0 Euros->That I want to get.!!!!!!!! 0answers 51 views ### Does anyone have a debugger that works in version 10.+? The debugger from mma version 10.0 to 10.1.0 is broken for me. I have Windows 8.1 64-bit. When I step through a function using the debugger then the function is run several times. This problem didn't ... 3answers 73 views ### Express block matrix in terms of matrix basis I'm trying to construct a function that returns the multiplication table of a matrix Lie algebra. Assuming a basis of matrices, my definitions: ... 5answers 6k views ### How to ask Mathematica to imitate Andy Warhol's pop-art painting? I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe's portrait so that it looks like Warhol's world famous pop-art painting. However, the result shown below is far from ... 2answers 153 views ### Are there any good mass row/column swapping functions for matrices? I have the following matrix Keeping the 20 row and 20 column fixed (so the 21st rows and columns because I started at 0)...how do I push each row and column back one spot? I need to push the 0th row ... 0answers 19 views ### Problem of HTMLFragment, strange output In the help page of HTMLFragment ... 3answers 152 views ### About the wrong evaluation of an integral Here is an integral I've been studying in my research and I've just realized that Mathematica 8.0 is unable to correctly compute it. I have 2 simple questions to ask: Is my code below correct? ... 1answer 54 views ### Efficient way to perform local Otsu thresholding on image I have images of cell nuclei that have locally varying intensity distributions. Therefore, I need a robust local threshold algorithm. LocalAdaptiveBinarize works ... 1answer 76 views ### Double integral over normal pdf gives inconsistent answer I am using Integrate function to do the following double integral ... 0answers 69 views ### How can I use L.Shifrin s code formatter package better in the document of HoldAllComplete, it says: Evaluate cannot be used to override HoldAllComplete.. for example, when I'm ... 1answer 31 views ### Creating a stream plot of nonliner diff equations [on hold] How would I create a stream plot (of eccentric closed curves) out of the following two equations ... 1answer 67 views ### an Integral that should be doable: Integrate[Cos[\[Beta]] Exp[I z Cos[\[Beta] - \[Alpha]]], {\[Beta], 0, 2 \[Pi]},Assumptions -> z \[Element] Reals] correct answer is [ I think ]: ... 0answers 42 views ### Optimal placement of points in 2D system [on hold] I woluld like to ask, how to arbitrarly place i.e. deploy (points) in 2D system, in such way to be with the nearest distance to previusly defined paths? Thanks! 0answers 49 views ### Double integral not evaluating in mathematica,though the functions in the integral give definite value [on hold] I tried integrating this: ... 3answers 194 views ### Writing code to update a large matrix? How can I write a code to update a matrix based on certain rules? I plan on constructing a large matrix, and I cannot submit entries one by one. The rules for the matrix are as followed:$$ ...
I want to integrate $$\int_{0}^{2\pi} dt_1 \frac{a + b*\cos(t_1 - t_2)}{c + d*\cos(t_1 - t_2)}$$ where $a, b, c, d, t_2$ are real numbers and $c + d > 0$ & $0 \leq t_2 \leq 2\pi$. I used ...