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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 ...
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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 ...
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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 ...
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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 ...
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176 views

Select positive elements from a list of solutions

I'm solving two equations with two unknowns ...
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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 ...
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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 ...
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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: ...
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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 ...
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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 : ...
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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 ...
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268 views

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

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

Solving Fredholm equation of the 2nd kind

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

Quickly Solving a High-Order Root System of Equations of Arbitrary Form

I have the following system of equations that involve some rather complicated exponents: $$ \left\{\frac{\mathit{a} \sigma ^{41/34}}{\mathit{m}^{8/119} \mathcal{M}^{28/17}}=1,\frac{\mathit{b}\mathit{...
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188 views

Make smooth plot from data

After some awesome tips from @qwerty I still have some doubts. As I said, I'd Like to make a smooth function with some other colors, I plot the graph, there is a lot of data. The situation is this: I ...
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50 views

Recursions where one definition depends on another. How to Block or have local variables?

I have been using Mathematica to solve a second order differential equation using the second order Verlet method. My code looks like: ...
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90 views

Eliminating one function from a nonlinear PDE

Is there any solution to eliminate function p[x,y] from these two equations which are equal to zero (diff1==0 and ...
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86 views

Maintaining working precision in my program

I am badly stuck with this program I am writing. I want output of program below to be precise up to 25 digits after decimal point. I am supplying all inputs with precision 25. But after each iteration ...
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102 views

Concerns about scheduled tasks

I'd like to know how CreateScheduledTask and StartScheduledTask work internally. When I run the following code: ...
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89 views

DSolve DAE echoing - no solution/response

I am aware that there are lots of questions about this topic but they are all slightly different. I am attempting to program a cybersecurity infection model and there are 4 states that a computer can ...
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112 views

solving an equation containing an complex integral

I want to solve a numerical equation which include an integral. The problem parameters are : w (is a complex : w = wr +I wi), <...
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223 views

Interpolation of 4D data on a triangular grid

I need to interpolate a function defined on a triangular surface (grid). The grid is defined as ...
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55 views

Problem displaying “/” correctly in exported svg file of Plot in Mathematica 8

In a plot, I use "/" on the axes labels to denote units. E.g. "t/s" meaning time in seconds. I believe this is pretty standard in Physics. ...
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166 views

Using a standalone CDF to replace a typical graphing calculator

I can use Manipulate[] to create a grapher that emulates some of the functionality of a typical graphing calculator.By using ...
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89 views

Problema with Grassmann Derivative: two solutions for the same function

I'm confused as to why mathematica is not giving me the correct answer. I'm using the grassmannOps package and defining $\theta$, $\bar\theta$ as grassmannians and $...
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115 views

LatticeReduce of a linearly dependent basis

l1 = {{-6327, 0, -2109}, {131, 0, -131}, {-6840, 0, 24929}}; LatticeReduce[l1]] returns {{1,0,0},{0,0,1}}. How do I find ...
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39 views

Why was notebook converted to single input cell upon saving?

I recently opened a notebook of mine and discovered all the various cells (input output, headings, graphics etc) had been converted into one big input cell, complete with date, time etc for each line. ...
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93 views

Can't operate on vector within a list of rules

I'm trying to set up a list of rules which includes the following: ...
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69 views

LatticeReduce question

Does LatticeReduce work with arbitrary precision arithmetic? That is, if I give it a linearly independent integer basis, but the integers are 40 decimal digits long ...
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129 views

Mathematica: Derivative appears to be wrong

I'm first getting f(x) by computing an implicit equation. Then I want to take the derivative. Later on, when I plot both f(x) ...
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82 views

Surface MeshFunction with independently spaced parameters

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130 views

How to graph the all of the possible isomorphic graph?

We can get one form of it use Graph ...
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91 views

Extract coefficients from sum

I would like to extract coefficients of indexed variables from a large sum. The following is an example motivated by linear regression to illustrate the problem. Consider the (unnormalised) log ...
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76 views

How to export heterogeneous data to single file?

I want to export structured heterogeneous data (containing images) to some standard file format. The expression to export can contain 3 atomic types: numbers, strings, images, and be nested with 2 ...
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81 views

Why does NDSolve and ParametricNDSolveValue show different memory manage in same loop?

This is a follow-up question about How to delete InterpolationFunction created by NDSolve/ParametricNDSolve?. In the previous question, J. M.♦ and Albert Retey showed $HistoryLength = 0 and Clear[] ...
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154 views

Speed up the Eliminate

I have problem of eliminating some variables from a set of equations, which contain logarithmic function, in order to obtain a differential equation. These are the parameter and functions in ...
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146 views

ensemble averaging

Herephixis $\phi_{xx}$ a coherence matrix and the angle brackets denote ensemble averaging. $E_x$ is the x component of the electric field. $$\phi_{xx}=\langle E_x^...
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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 ...
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86 views

Trouble solving system of nonlinear equations with piecewise

Here is my code so far ...
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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 ...
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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'...
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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 ...
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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 ...
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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 \ ...
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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 ...
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64 views

Non-existent PDF for combined MixtureDistribution and TransformedDistribution?

I am trying to mix two discrete distributions, one of them shifted by an integer amount by means of TransformedDistribution. When I then try to access the mix, it responds to CDF but not PDF. This ...
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88 views

How-to carry out a set of operations on a large set of three-dimensional vectors in most efficient manner?

Problem description Essentially, I am trying to carry out a set of operations on a significantly large set of coordinate data. The coordinates in the data set represent a uniformly distributed set of ...

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