# All Questions

8,013 questions with no upvoted or accepted answers
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127 views

### How to determine side-effects in parallel computation? Possibly associated to Kernel not closing reliably

I have written a bunch of code to simulate some measurements. To speed things up, I intended to obtain the measurement values via a ParallelTable. However, it turns ...
42 views

### Does exist any equivalent of the function Cells?

May be I'm wrong but the function Cells is absent in Mathematica versions prior (at least) 8.0.1. Perhaps what is now natively built in was before implemented as a ...
125 views

### Kovacic's algorithm

Kovacic’s algorithm is used to find out whether or not an ODE has a Liouvillian solution, and if it has, then what that solution is. My question is: Is there any code written in Mathematica for ...
67 views

### EvaluationMonitor and variables with indices + subscripts

I have encountered the following problem while using EvaluationMonitor with NMinimize: variables that have both a subscript and ...
176 views

### Select positive elements from a list of solutions

I'm solving two equations with two unknowns ...
277 views

### Slow and laggy animation of an electromagnetic wave

I made a manipulate code of an electromagnetic plane wave which works relatively well, but is very slow and laggy for what it does (showing just a bunch of rotating or oscillating arrows). What is ...
153 views

### Solving general system of equations

I want to find the closed form solution to a general system of equations. The number of equations and variables is C. How do I specify the system of equations? If ...
75 views

### NDSolve: problem due to boundary conditions

I am trying to solve a 2nd order ordinary linear differential equation (DE==0). Here is the code: ...
78 views

### Is this problem parametrically solvable or it can just be solved for specific $\sigma$ and $\theta$?

In order to solve This problem: What is the maximum value of coefficient fv with the constraint that the matrix is positive semi-definite?, I have used the following code (Determinant is computed by ...
113 views

### How to define an exclusion zone for NDSolve

I need to numerically integrate a differential equation and define two exclusion zones to stop the integration. The Mathematica code looks like this : ...
84 views

### Fourier-style solutions to differential equations, not piecewise polynomials

NDSolve returns piecewise polynomials. Is there any way I can get a single (non piecewise) function consisting of sines and cosines instead? Sort of a "Fourier approximation" to the solution of my ...
268 views

### FindInstance—why doesn't it work with my expression?

I want to find arbitrary solution of a system of equations: ...
77 views

### Popup window shows after kernel closed when using J/Link

A popup window always show after kernelLink.close(); And this only happen after expression evaluated as graph. Such as ...
67 views

### Personal Reminder with Speak capability repeats multiple times

I am trying to create a personal reminder for myself using the Speak function in Mathematica hoping that the computer speaks the task only once at the designated time. However, I have found that the ...
283 views

### Solving Fredholm equation of the 2nd kind

While I was using the code from here to solve this integral equation: ...
157 views

### Help numerically solve this non-linear PDE with singularity

I have trouble finding a numerical solution to the partial differential equation below. It seems to be a singularity in the solution somewhere, so I searched online and found that it is suggested to ...
39 views

74 views

### Time needed to solve NIntegrate is much longer than what I was expecting

I'm trying to do the following list: tablevdip = ParallelTable[{x, y, Vdip[x, y, 6]}, {x, -1, 1, .5}, {y, -1, 1, .5}];] with ...
86 views

### Trouble solving system of nonlinear equations with piecewise

Here is my code so far ...
127 views

### Nestlist inside Compile

My question is a continuation of question1 and question2, but I think it may be considered as a self-contained one. I am interested to make the following code faster ...
49 views

### Tips on finessing Reduce[] with inequalities

Reduce[] sometimes solves inequalities I give it, sometimes it doesn't. Is there some general principles I'm missing or some common pitfalls I'm falling into? For example, here is easy problem I can'...
35 views

### Solve involving simple cancellation on both sides fails when there are too many constants

I've been working with a number of equations of the form x = A * B * x ^ C where I need to solve for x--basically, equations ...
158 views

### Overwriting a file with export[SystemDialogInput[]]

When I use the following code: Export[SystemDialogInput["FileSave", "myP1P3bmp.png"],Image[myBitMap, "Bit"], "PNG"]; I get a somewhat unexpected behavior. I can ...
163 views

### Replacing parts of a complicated expression with shorthand symbols

I have a list, each element of which contains a different complicated expression. Here is a simplified example of the first three entries of the list, displayed one above the other: \$\frac{Ey \ \mu \ ...
86 views

### Multivariate remainder of polynomial in respect to a set of polynomials

I would like to have a really fast routine that computes the so called Normal Form of a multivariate polynomial f in respect to a set of other multivariate ...