-1
votes
0answers
48 views

What does F[[1]] mean? [on hold]

I defined a function "F" and checked length, then I wanted to select terms I needed, and failed. One of my friends said I should typed something like that: ...
0
votes
0answers
35 views

Topics for master's project using Mathematica [on hold]

I wish to do 1 year project in linear algebra using Mathematica. What are linear algebra topics which can be implemented on Mathematica as part of 1 year graduate level dissertation.
1
vote
1answer
94 views

4th-order Runge-Kutta method to solve a system of coupled ODEs [duplicate]

I am a beginner at Mathematica programming and with the Runge-Kutta method as well. I'm trying to solve a system of coupled ODEs using a 4th-order Runge-Kutta method for my project work. I have ...
2
votes
1answer
94 views

Proving positive definiteness or semi-definiteness of a matrix

I have the following 4x4 real symmetric matrix: $K=\begin{bmatrix}3-3w & -\frac{4}{3}+a+2w & \frac{5}{12}+b-\frac{w}{2} & 0\\ -\frac{4}{3}+a+2w & -1-6a-3x & ...
1
vote
0answers
33 views

How to use RunProcess to run python interpreter

In a related question How to use RunProcess to import external function? @taliesin provides a very nice answer illustrating using RunProcess to launch a GO http server. Has anyone, or does anyone ...
2
votes
4answers
156 views

Using Map sequentially

I'm trying to simulate the probability of a balanced hand in Bridge (The Theory of Probability by Santosh S. Venkatesh, 2013) using Mathematica. The problem is solved in the textbook but I just wanted ...
1
vote
2answers
63 views

How to make legends in Graphics?

To make an equilateral hexagon, here is my code in mathematica: ...
1
vote
1answer
49 views

Writing cells from other notebooks into current notebook?

I have a large number of Mathematica notebooks which contain study notes for different topics (as opposed to actual Mathematica Code). I'm trying to develop some code to randomly pull parts of a ...
1
vote
2answers
55 views

NotebookWrite in EvaluationBox forces Input CellStyle

There is a promissing new function EvaluationBox[] and a nice last example in documentation section for it: ...
1
vote
1answer
32 views

How would I set the equation number for an EquationNumbered cell?

Regardless of how many EquationNumbered cells are above or below, every new EquationNumbered cell that I add in my notebook shows (1) as the equation number. Is there a way to correct the equation ...
1
vote
1answer
79 views

How can I simplify a triple integral with exponentials?

I want to simplify the following triple integral with exponential terms. \begin{equation} \int_0^\infty\int_0^\infty \int_0^\infty \frac{1}{R\,G} e^{-p(1+R\,a)-q\, b \frac{1+R\, a}{1+G\, x}}\, ...
2
votes
1answer
79 views

speeding up creation of SparseArray

I have to create the following sparse arrays, which are reshaped in a two dimensional matrix, so that i can use the build in Dot[] function to do a kind of ...
11
votes
5answers
423 views

Opposite of StringSplit

What is an appropriate command that does the opposite of the following. StringSplit["a b c d e f g"," "]
1
vote
0answers
248 views

Mathematica 10.1 availability [on hold]

According to this post and this page of the Wolfram Documentation Center a new Mathematica version is on the way, if not already available to some user. It'll be v. 10.1 and, as such, a rather major ...
1
vote
0answers
35 views

DateObject from AbsoluteTime broken

In the middle of a session (10.0.2 / Win64 / 2.7Gb working set - peak was over 7Gb) the form/definition for DateObject from an integer has disappeared. ...
4
votes
1answer
197 views

Lagrange Multiplier

We are asked to maximize and minimize $f(x,y)=4xy$, given the constraint $4x^2+y^2=8$, using the Lagrange Multiplier method. First, I enter the functions f and g. ...
2
votes
1answer
68 views

How can I get “custom” controls to appear and behave like “default” controls in my Manipulate?

For various reasons I need to define some controls in my Manipulate with complex behaviors that are not (or at least I don't think can be) accomplished using the ...
0
votes
0answers
37 views

Boundary Value Problem Errror [on hold]

I have a first order differential equation such as $\quad \quad d/dt (u[x,t]) = - u[x,t]\,u[x,t]$ with the boundary conditions $\quad \quad u[0, t] = 0,\ u[L, t] = 0$ where $x$ is between $0$ and ...
1
vote
0answers
23 views

Speeding Up the Numerical Integration of a Product of Numerical Integrands with NIntegrate

I need to solve a set of coupled integral equations within a self-consistent cycle. The final result will be functions, say $A(x)$ and $B(x)$, which are related to each other by some integrals which ...
1
vote
1answer
122 views

Integrated Solution Graphics [on hold]

I want to draw this nonlinear differantial equation' graphic with other solving equation (in same graphic). ...
6
votes
1answer
51 views

Solving a PDE with a spatially piecewise-constant material parameter

I would like to solve equation for the 2D distribution of an electrical potential in the conductive medium: $$\nabla\cdot(\sigma\nabla f) = 0$$ where $f=f(x,y)$ is the electric potential (in 2D) and ...
0
votes
0answers
52 views

Is there a way to create a two column page layout in a notebook? [duplicate]

I am working on a white-paper that requires a two column format. Is there an existing Stylesheet that can be used or a way to create a Stylesheet that supports this Mathematica?
4
votes
2answers
116 views

Well-defined symbolic integral leading to ConditionalExpression

I would like to determine a closed-form expression for the following symbolic integral $$ \int_{-1/2}^{1/2} \!\!\!\! \mathrm{d} x \int_{-1/2}^{1/2} \!\!\!\! \mathrm{d} y \, \frac{1 + b x + c y}{1 + e ...
1
vote
1answer
81 views

How do I smooth or remove jitter from an exported Graphics3D plot?

I have exported a Graphics3D plot as gif. But the plot shows jitter (You can see the yellow ball shows somewhat slight move around, which is expected to be still). How does this happen and how to get ...
0
votes
1answer
60 views

DensityPlot and KroneckerDelta

I have the following DensityPlot: DensityPlot[Sin[x] Sin[y], {x, -Pi/4, Pi/4}, {y, -Pi/4, Pi/4}, ColorFunction -> "SunsetColors", PlotLegends -> Automatic] ...
5
votes
1answer
90 views

Comparing memory consumption of two pieces of code

I have implemented something I want to do in two different ways, because I'm not sure which of the two approaches give best speed/memory efficiency. Comparing the speed of the two approaches is ...
0
votes
3answers
68 views

Filtering the output from Table and export it into excel

I have the following functions ...
0
votes
0answers
43 views

Call functions from a notebook inside C#

Is there a way to use functions from a notebook in C# with NETLink ? I found only this: Evaluate Notebook from .Net, but it is not of much help. Any suggestions ?
0
votes
1answer
24 views

How can i specify a NotebookSelection by a given CellObject?

My Questing is very simple. If I have a CellObject e.g. CellObject[Text], I can move the selection to this ...
0
votes
0answers
36 views

Problem in deriving general equation [closed]

I have a problem to derive a general equation in Mathematica. The code below supposedly computes the intersection area What modifications should I make to the code to derive the area in terms of ...
6
votes
1answer
52 views

DatePlus and DayPlus perform much worse than my user-defined-function

I was debugging a function speed, and discovered that the time bottleneck was in DatePlus. I tried to change to DayPlus and get ...
3
votes
1answer
44 views

Ordered associations

Mathematica 10 has introduced Associations, elsewhere known as hash tables or dictionaries. Is there Ordered equivalent like in Python, Java, .NET? The data structure should remember the order in ...
4
votes
5answers
249 views

How do I write a condition for Position that uses both the current and previous element?

For example, given {57, 3, 40, 94, 9, 84, 81, 93, 76, 5, 7, 76, 38, 9, 23, 95, 49, 0, 30, 3} I'd like to get all the indices at which the elements cross from ...
0
votes
0answers
29 views
0
votes
2answers
38 views

Defining the domain of positive real numbers

I am trying to solve an equation by assuming that all the variables are real and strictly positive. I can use the keyword Reals for the argument ...
8
votes
3answers
350 views

Turning a set of random walk data 45 degrees

I have a set of data that is just a "random" (generated by me, not by computer) sequence of length 2000 of 1's and (-1)'s. I used it to plot a 1-D random walk where +1 is step up, (-1) is step down, ...
0
votes
1answer
40 views

Plot 3D with conditions and variables dependent on each other

I m trying to do something like this: ...
0
votes
1answer
44 views

FindRoot, Loops and multivariate nonlinear system

I posted a question yesterday asking how I could get all the solutions to my system of 4 nonlinear equations with 4 unknowns. I gave up on this since it seems ...
0
votes
0answers
50 views

If the earth's rotational speed increased by 2% each day starting today…what would be the difference in age 20 years from now? [closed]

If the new adjusted revolution of the earth still equaled one day and 365 days still equaled one year, how old would someone be 20 years from now (20 years based on the current rotation of the earth) ...
1
vote
0answers
28 views

How to debug an existing notebook in Workbench

I have an existing notebook that I want to debug in workbench. This notebook is a self contained program that does not use any .m files. From what I can tell from the Workbench documentation you ...
0
votes
0answers
23 views

How to identify primary keys in an existing database table

I would like to identify the primary keys in a DB table using DatabaseLink commands trying to exclude SQLExecute. It seems like SQLTableInformation or SQLColumnInformation may not show that ...
3
votes
2answers
60 views

Memory Problem with Modules and NDSolve

I'm using NDSolve inside a module, and I appear to have a memory leak. The relevant code is: ...
0
votes
0answers
25 views

about Updating Wagon's FindAllCrossings2D[] function [closed]

I am working with the shortest version of FindCrossings2D, which was provided by Vitaliy Kaurov. Here is Vitaliy's function: ...
-1
votes
0answers
80 views

Finding R^2 and R^3 of relations [closed]

Let R be the relation on the set { 1 , 2 , 3 , 4 , 5 } containing the ordered pairs (1 , 1) , (1 , 2) , (1 , 3) , (2 , 3) , (2 , 4) , (3 , 1) , (3 , 4) , (3 , 5) , (4 , 2) , (4 , 5) , (5 , 1) , (5 , ...
0
votes
2answers
30 views

Parallel evaluation hangs before doing anything

[I use Mathematica 9.0.1.0 on OS X Yosemite 10.10.2.] I am experiencing difficulty with parallel evaluation that I am finding extremely perplexing to troubleshoot. I define the following function in ...
4
votes
4answers
130 views

Get Axes Range of Plot?

Say I have some plot plot = Plot[Sin[x], {x,0,10}] (*as an example*) Is there a way I can get the x and y axes min/max values from the "plot" variable? If I ...
0
votes
1answer
92 views

Simplified expression is different than original

I have a question regarding the Simplify command in mathematica. I am working with a 4 x 4 table called Eqs, filled with symbolic expressions. I then do ...
7
votes
2answers
131 views

Mathematica on Raspberry Pi

Can I develop BSD/MIT open-source library for Mathematica using free non-commercial version on Raspberry Pi? To state it differently: does the non-commercial limitation of Mathematica on RPi limit ...
3
votes
1answer
49 views

How to change line lengths in LineLegend

How can I shorten the lengths of the LineLegend[] lines in the following plot? Is there a way to control line spacing as well? ...
0
votes
0answers
23 views

FindMaximum slow for fixed parameters

I hope my problem can be solved by just showing you this tiny part of my code which does not run on its own. I have an optimization problem and want these functions to work on various data sets. ...

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