# All Questions

2answers
80 views

### Plotting logistic maps

I have a question about plotting in Mathematica in general, and this particular recurrence relation as an example: $\qquad x _{n+1} = rx_{n}(1-x_{n})$ How can I plot the following plots as shown ...
1answer
159 views

### NDEigensystem returns incorrect eigenvalues for 2D coulomb problem, eigenfunctions contain discontinuity

I posted a similar question a short time ago regarding the 3D Coulomb problem. Jens' excellent answer to this thread allowed me to obtain the correct eigenvalues and eigenenergies for that system. I ...
1answer
69 views

### Interval arithmetic for DawsonF (or other special functions)

I am currently trying to estimate a complicated expression involving DawsonF using interval arithmetic. The interval arithmetic is partially supported by ...
1answer
30 views

### A question on JordanDecomposition in Mathematica

How can I have Mathematica show me also the inverse matrix of the similarity matrix of JordanDecomposition of a matrix? Obviously I need to use here the ...
1answer
29 views

### List of Inequalities in RegionPlot with different colors [duplicate]

Starting from the example of the Documentation: RegionPlot[{x^2 < y^3 + 1, y^2 < x^3 + 1}, {x, -2, 5}, {y, -2, 5}] Which gives a nice plot with two ...
1answer
30 views

### Importing an .eps file failed in the latest version of mathematica

It was quite straight forward to import an .eps file (also pdf and other formats) into a script, with the version 10.0. that I had before; but, since I upgraded my Mathematica to the latest version ...
0answers
30 views

### differentiating an integral [on hold]

I am new to Mathematica. i hope to have the software next week so please excuse the unusual syntax. p(y) means p is a function of y. u(p) means u is a function of p . p(x) is the value of p when y=x ...
1answer
41 views

### Run several input cells in parallel

I have a notebook with several input cells that produce data which is then plotted into separate graphs. Since I do not want to save the results, because it makes the file huge, I keep the ...
1answer
39 views

### Plot for function that calculated direct with while, but is piecewise

For this question Use of {FOR, Do, If,Plot} that ..., I wrote this code: ...
0answers
25 views

### Plot3D gives an empty box [on hold]

I have two questions. I am trying to 3d plot a function like in the image below. It gives an empty box displaying no results. I tried adjusting the graphic qualities, but it does no solve the ...
0answers
17 views

### Measuring space complexity?

I like using GeneralUtilities function BenchmarkPlot for estimating time complexities, is there something similar for ...
1answer
185 views

4answers
52 views

### Matching a Table and a List and building a new Table

I have a Table which includes {Numbers, Probabilities}. For example A= {{1,0.5},{2,0.25}, {3,0.1},{4,0.9}……{100,0.1}}. Put attention that the numbers are 1,2….100 in order. I have a List of random ...
1answer
68 views

### Plotting a convex hull with a coordinate mesh

I am plotting the convex hull of some curves by extracting the curves from a contour plot and constructing the convex hull around their discretized version . It's not terribly accurate for ...
1answer
53 views

### Using Mathematica to batch-produce text files

I need to make a bunch of plaintext files, all of which differ only in a single parameter. The text I want to "copy" or "batch produce" is a little bit complex, since it contains quoted areas and ...
1answer
33 views

### An unexpected NDSolve behavior [on hold]

I observe the following. The code: ...
0answers
20 views

### Make an existing solution for monitoring parallel jobs robust against dying kernels

Is there any chance to make the solution by @David here http://mathematica.stackexchange.com/a/1562/21606 more robust in the following sense: In my case, some parallel kernels die regularly during ...
1answer
185 views

### Odd Coloring with GeoRegionValuePlot

Bug introduced in 10.0 and persisting through 10.3 or later Bug behavior is version dependent When I'm plotting data with GeoRegionValuePlot, I'm getting some ...
0answers
28 views

### Setting Initial Conditions in a System of Differential Equations that don't start at t=0

I have a system of six differential equations (linear for the sake of the discussion). I want to set the initial condition to start at time t=18 and not time t=0. I know the values of the dependent ...
2answers
230 views

### How do I encode this replacement rule?

I'm pulling a 5x5 array from a larger array. The small sub-array (call it S) can contain any combination of the symbols A, B or 0. What I'd like to do is: if the array contains any matching pairs ...
0answers
50 views

### CopyToClipboard freezes FrontEnd

This is freezing the FrontEnd: CopyToClipboard@ExampleData[{"Text", "AeneidEnglish"}] Are there system limits I'm hitting here?
0answers
27 views

### Solving Time-Dependent PDE's Analytically with no non-trivial Boundary Conditions

I'm having some trouble solving a partial differential equation that is supposed to model the propagation of a scalar field in Schwarzschild spacetime using spherical coordinates. I'm using the DSolve ...
2answers
50 views

### How to find intersection points of linear and semi-logarithmic plots

Hopefully the title depicts what I am trying to do. Below is a figure of my calculations that is shown in logarithmic scale in the x-axis. I am trying to find a way to find the intersection point at ...
0answers
29 views

### A function for replacment in mathematica [on hold]

when you have too many replacements such as a1 x+ b2y + c1 z/.{a1->s^2+b^2,b1->r^2+g^2,c1->f^2+k^2} is it possible to define a vector like this ...
0answers
28 views

### how to know two aircraft getting far away each other? [on hold]

Dataset: my algorithm is: calculate velocity vector each aircraft ...
0answers
40 views

### How to find the concave points of a point-set?

To solve the boundary of a set of planar geometry, I sampled $6$ graphs, then using RunnyKine's approach. ...
0answers
44 views

### Why can Mathematica compute numerical sums more efficiently when they are written as matrix operations?

Let $f(n)$ and $K(n,m)$ be functions such that the double sum, which we wish to evaluate numerically, $$\sum_{n=1}^a \sum_{m=1}^a f(n) f(m) K(n,m)$$ exists when $a$ is some large positive number. I ...
3answers
244 views

### Complex limit gives wrong answer

I'm evaluating $$\lim_{z\to e^{i \pi/2 n}} \frac{z-e^{i \pi/2 n}}{z^{2 n}+1}$$ with Mathematica 9.0.1: ...
0answers
37 views

### EventLocator in NDSolve seemingly hogs memory in Windows, but not Mac

I have written a function (ftest in my code) which does the following: Takes a vector {x,vx,vy} as input Numerically solves (with high precision) a specific ...
1answer
64 views

### Is it possible to find the close form solution of following Recurrence relation using Mathematica?

Example 1 F(0,t)=t F(n+1,t)=F(n,2*t) Example 2 F(0,y,t)=t F(n+1,y,t)=F(n,y+1,t*y) When I tried to manually solve above ...
2answers
161 views

### List of Recently Opened Files

If I go to the menu bar and press File I get a list of recently opened files.This would be useful except they are edited and mostly replaced by dots thus making choosing difficult. See the screen shot ...
1answer
69 views

### What's the easiest way to find the closest point in a list of pairs?

I frequently end up in this situation. I have a solution, but I suspect it's the dumbest way of doing it. Frequently, I'll have a list of pairs, for example: ...
0answers
56 views

### Learning Mathematica for Math Majors [duplicate]

I just downloaded Mathematica and I'm taking a course in Multivariable Calculus. I realize there is a lot of complexity to Mathematica and there are Many types of learning resources out there. I was ...
0answers
34 views

### EPS Files + Too many points with ListPlot [duplicate]

So, basically, I have this ...
1answer
64 views

### Output short denominator as pre-factor

How can I make the output print like the input, with the short denominator written as a factor in front of the long expression? I was messing with styles earlier today to do something else, and at ...
1answer
59 views

### what is wrong with this plotting code? [on hold]

Heres the question: The region bounded by f(x) = x+2 and g(x) = sin(x) between x = 0 and x = Pi/2 i. Plot the region on the interval [0,Pi/2], between y = 0 and y = 4. ii. Find the area of the ...
1answer
43 views

### NRoots Results: From Equations to List of Root Values [on hold]

When I use Roots/NRoots, I get a disjunction of conditions as result. The conditions are normally of the type x == value How can I convert this to the list of root values?
2answers
69 views

### Write list of strings to a file (as lines)?

I have a list of Strings, like: list = {"hello", "world", "other line"}; And I want to write it to a file, so that each item in ...
1answer
65 views

### Prevent evaluation after ToExpression

How can I produce both typesetting and evaluation of a LaTeX expression? Illustrative example: The evaluation of HoldForm[Sqrt[2.0]] == Sqrt[2.0] looks ok (aside ...
0answers
56 views

### Can you help me reduce this? WolframAlpha's search bar has a character limit [on hold]

Trying to find the pursuit curve for the following illustration: First equation of motion: ...

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