# All Questions

153 views

Lately I come across what I think not uninteresting problem which is a good exercise for the usage of Dynamic. Assume you have files in a directory structure (a ...
169 views

### How do I plot Numerical Range of two hermitian matrices

Let $A_1$ and $A_2$ be two $3\times 3$ hermitian matrices. Then their numerical range is defined as two-dimensional set \begin{align} \mathbb{S}=\{\left[u^HA_1u,u^HA_2u\right]\in ...
212 views

### Replace elements in a list

Suppose that I have a list: ...
1k views

### Write C/C++ programs calling Mathematica functions

I need to write a C/C++ program and call some functions in Mathematica especially those like Solve or NDSolve. The problem is ...
205 views

### Derivatives of list elements

Could someone explain the odd behavior of the Derivative function when drawing arguments from lists? We have, ...
96 views

### Compiled function crashes kernel when trying to list over different length arguments

I'm trying to speed up a tally/binning operation that I have to run many times. I have many lists of between 1 and 10 numbers from the range [1,5] and I want to ...
111 views

### SetPrecision with indexed variables

I have an expression as below: ...
408 views

### Infinite Expression Error from NDSolve

I am trying to solve a differential equation numerically. So I have ...
627 views

### Mathematica giving infinity as a random number!

I am trying to generate several random numbers from normal distribution using Mathematica. The following is the relevant code: ...
168 views

### Map several functions in one routine

I have several functions, let's assume they are: func1[x_]=x; func2[x_]=3*x-5; func3[x_]=0.1*x^2; and a lot more like these. For each and every one of these I ...
166 views

### List comparison in constraints for Minimize

I am trying to solve an optimization problem, a simplified version of which is as follows: ...
93 views

### shortest paths in probabilistically weighted edges? [duplicate]

I understand Mathematica can find shortest paths. However, is it also able to find the most probable paths? I mean this is a case where edges are given probabilistic wights (from 0 to 1) and the most ...
165 views

### Exploiting self-adjointness when changing basis

I am using Mathematica to analyze a real, self-adjoint matrix $H$ of the size $32 \times 32$, which comes from a physics problem. In the picture there is also a matrix $Q$ which commutes with $H$. I ...
128 views

### Nest for large value of n

I am working on a problem to find the Feigenbaum constant. In this problem I have to get $f^{2^n}(1/2)$ with $f(x) = kx(1-x)$. I use Nest to get $f^{2^n}(1/2)$ but ...
174 views

### Conjugate and simplify

I want to get a cosine from taking the real part of a complex exponential: $cos(x) = Re(exp(i x))$. What I do in Mathematica is ...
214 views

### Import large amount of data with time stamps

I have a large data file (150 000 lines) which I want to import in Mathematica. The first few lines look like this ...
99 views

### Significant platform-dependent efficiency when importing data?

I'm curious, as I understand that answer this way: If you are using a Linux derivative or something like cygwin on Windows, then this is an efficient solution for reading only the third field ...
125 views

### Solving a system of equations

Mathematica doesn't want to solve my exact system with 3 equations and 3 variables. ...
129 views

### How can I stop DiscreteMarkovProcess[] from relabeling vertices?

I'm attempting to calculate the mean first passage time between two vertices, $v_1$ and $v_2$, provided some undirected graph $G$. However, I noticed that running the following script: ...
292 views

### Problem with NIntegrate when WorkingPrecision is specified

I am trying to evaluate this integral numerically: $$\int_0^{\infty } m \exp (-m) J_1(m){}^2 \, dm$$ Everything is OK when only the integration method is specified: ...
218 views

### List plot 3D not showing correct data

I have a list of values of the form {{a_1,b_1,c_1},{a_2,b_2,c_2}...} where a goes from 0 to 30, ...
316 views

### Efficient drawing of convex polyhedron given a set of points [duplicate]

I have a set of points in the 3D space and I want to draw the bounding convex polyhedron of those points. A very naïve solution would be to draw a triangle between every three points: ...
270 views

### Mathematica not able to confirm its own solution to differential equation

I type the following into Mathematica: DSolve[q''[x] + 2 x/(x^2 - 1) q'[x] - 4*q[x]/(x^2 - 1) == 0, q[x], x] It gives me the result ...
77 views

### What algorithm is Mathematica using for FirstPassageTimeDistribution[]?

What algorithm is Mathematica 9 using for FirstPassageTimeDistribution[]? Is it attempting to use PseudoInverse[] on the ...
647 views

### Peirce's quincuncial projection

The Peirce quincuncial projection is the cartographic projection of a sphere onto a square. In short, I would like to see it implemented in Mathematica. Here is my code: ...
529 views

### How do you draw a straight line with PolarPlot?

I can't figure how to draw a line with PolarPlot. A vertical line through a is $r \cos(\theta) = a$, so ...
167 views

### iterate method to find roots

This code gives the roots (lambda-values) of eq1 by using iteration. ...
583 views

### Viewing Mathematica Demonstrations Project Code

I hope I am going insane and the I'm not seeing the snake about to bite me... How does one view the code in the demonstration projects that one can download from wolfram.com? It seems like all of ...
192 views

### Efficient Data Entry / Manipulation with Many Datasets

I currently have a simple task of graphing many different datasets (26 here, with many different instances where I'll need to do, say, 26 different ones from the same template). I'm trying to ...
455 views

### How do I create an ellipse bubble chart?

I have some data that I would like to plot as a bubble chart. The data is formatted as {{val1_mean,val1_sd,val2_mean,val2_sd},{val1_mean,......}}. What I would like to do is plot a bubble chart where ...
618 views

### Arcs of rotation for angles

How can I draw trigonometric angles of any radian measure associated with the unit circle, complete with the x-axis and y-axis? How can I draw arcs of rotation inside positive or negative angles? Is ...
293 views

### Export matrix to $\LaTeX$ with style

Is it possible to export a matrix to $\LaTeX$ with style? For example this code will create a matrix with equal spacing matrix and with background colors in some cell, is it possible to export that ...
801 views

### Importing several huge files with headers & footers

having here several files in ASCII format http://ge.tt/91rv0Jf/v/0 I want to import, while removing headers and footers and then join the several lists. ...
200 views

### How to rewrite this function to be faster: Find sub-matrixes of boolean board which imply a given boolean pattern

I have Boolean matrix A (called "board") and Boolean matrix B with smaller dimensions (called "pattern"). I am trying to find sub-matrixes C of A such that C has same dimensions as B, and ...
121 views

### Defining an Implies operation that works for Boolean matrices

I have two Boolean matrices, that both have dimensions m x n. I want to create a function TableImplies, which would return True ...
224 views

### Custom (Frame)Ticks fail when using Mathematica's script engine

I want to define my own ticks in a DateListPlot. It works quite well when I use the code in a Mathematica Notebook but breaks somehow when using it via ...
84 views

### Edit AxesLabel from an existing plot

I have a really complex function that takes a few hours to plot as a function of a parameter. Few days later I realised that I named the axes wrong. Is there an easy way to edit the AxesLabels without ...
211 views

### How to integrate ParametricNDSolve solution with respect to a parameter?

I have just upgraded to the new version of Mathematica because of its new built-in ParametricNDSolve function. I need to solve a first-order non-linear ordinary ...
306 views

### Problem with WhenEvent

I am trying to add a time dependent fraction to a parameter in NDSolve, i.e. when 10 < t< 20, add ...
33 views

### Plot derivative of integral with changing limits [duplicate]

My code is: Plot[D[Integrate[E^(t*(-x^2)),{x,t+2,t^2}],t],{t,-2,3}]. The errors/warnings are: ...
651 views

### Network database access - How do I connect to a remote database?

I am able to connect to a specific MS Access Database when it is on the same Windows computer as Mathematica via the command ...
148 views

### Manipulate keeps replaying the animation non-stop

I made a notebook with the following code, but for some reason when I evaluate it it keeps replaying repeatedly. What is causing this? Thanks. ...
2k views

### Graphics3D: Finding intersection of 3d objects and lines

I found these two nice links 1) intersecting graphics 2) Implementation of Balaban's Line intersection algorithm in Mathematica which works for 2d. However, I need to find whether a ray(line) ...
751 views

### How do I get Mathematica to show a number in non-exponential form? [duplicate]

Sometimes I make a calculation in Mathematica that produces a big number, which Mathematica shows like so: -1.52522*10^7 This is annoying to me, because I want ...
116 views

255 views

### How do I manipulate a 3D point plot?

I currently have a recursion done in 3D. At the moment, I am able to manipulate the points, but I cannot use "Joined->True" to connect them Currently this is what I have ...
59 views

### How to retroactively merge cell change history according to a merge interval

I recently noted that there is an option in the options inspector to set a merge interval for cell changes. This (I think) prevents a quick series of changes from spamming your notebook history with a ...