0
votes
0answers
2 views

Selection of all the objects with the same style in a notebook

In a notebook, I would like to select all the cells with the "Text" style to change their style. How is possible to do this with a automatic process ? For the moment, I can to do it only cell by ...
3
votes
2answers
165 views

How do I plot a space curve as a ribbon?

I know Mathematica has a built in Tube function, but I want to be able to change the parameters of a ribbon and visualize that. Is this possible? How do I do this? ...
0
votes
0answers
4 views

Button to close cells

I want to have a button that closes cells with a specific tag. The following code does what I want: ...
0
votes
0answers
14 views

using solve command

I used solve command to solve a set of nonlinear equations and got this error: Solve was unable to solve the system with inexact coefficients or the system obtained by direct rationalization of ...
0
votes
3answers
297 views

Solving an equation takes too long

I am trying to solve the following equation func[a, b, c, d, e] == 0 where ...
2
votes
1answer
58 views

Combine three 2D graphics with animation

I am trying to simulate three kind of points (different color) entering a 2D rectangular region from different sides with animation. Below is my code: ...
0
votes
0answers
71 views

Schrödinger equation for Hydrogen atom

I'm trying to solve Schrödinger 1D equation for hydrogen atom but I found several difficulties. To get in context I want to solve this equation For Z and l real and arbitraries. To start with I ...
11
votes
1answer
2k views

How was Mathematica built?

I've been wondering this for a while now: How was Mathematica built? Is it written in Haskell? C++? I'd love to get a taste of the wizardry behind this incredible software.
1
vote
1answer
58 views

LinearModelFit: How to compute R-squared? [on hold]

Is there a simple way to computed the R-Squared(adjusted and not adjusted), from the LinearModelFit? It has so many options, but none for the R-Squared, that I suspect there's a simple way to compute ...
0
votes
2answers
65 views

Expression of an integral

I am doing the following integral in Mathematica with $a>0$, $\iint e^{ -\left ( x_{1}+x_{2}-2b \right )^2/\left ( 4a \right )}dx_{1}dx_{2}$. My code is ...
8
votes
7answers
533 views

Brackets around each item in matrix

I have a matrix where every item in the matrix has its own brackets that I do not want. How can I remove the brackets around each item?
5
votes
0answers
40 views

Contour labels on SliceContourPlot3D?

SliceContourPlot3D doesn't seem to come with the option of putting contour labels on the plots as far as I can see. I'm using the ...
4
votes
3answers
172 views

sum involving binomial coefficient

To evaluate $ \sum_{\substack{\text{even }k\\ 2\leq k\leq m-2}} \binom{m-2}{k-1}(k-1) $, where $m$ is an even integer. Running the following in Mathematica 10.3.0 (October 9, 2015) ...
1
vote
1answer
86 views

How to Minimize an NIntegral

My problem is to minimize in Mathematica a numerical integral. The command FindMinimum[With[{R=2.5},NIntegrate[(R*r1*a)*Sin[r1*a],{r1,1,R}]],a] does calculate ...
4
votes
1answer
68 views

Is it possible to recover the efficiency of ListConvolve when generalizing the convolution?

I've noticed that, while ListConvolve is very fast, it becomes much slower when you use anything but the standard Times,Plus as ...
0
votes
1answer
37 views

Issue with replacement rules screwing up a matrix

I am pretty new to using Mathematica as more than a calculator. Essentially my problem is that I am trying to calculate a quantity vector quantity $x=x_0 - A^{-1}F(x_0)$ where $x_0$ is a 3-entry ...
2
votes
0answers
33 views

Reaction-diffusion PDE with NDSolve: either very slow or very inaccurate

I am struggling to have Mathematica 10.3 solve a system of PDE's (with periodic boundary conditions and random initial conditions), but either it produces a set of very noisy InterpolatingFunction ...
0
votes
0answers
46 views

NMaximize is not doing what I intend [on hold]

Why does NMaximizegive the wrong answer in following script: ...
12
votes
2answers
199 views

upper envelope of data

Here is a ListPlot[] of some data. Clearly, there is a fairly smooth upper envelope - the question is whether there is an nice way of extracting it...
4
votes
2answers
54 views
2
votes
1answer
127 views

Simple code to write differential equations in a matrix formulation

Is there a simple code to transform the following differential system equations : ...
10
votes
3answers
223 views

Reproduce image effect in Mathematica

How do I create the "dotifying" effect below in Mathematica? I have tried to use Rasterize first to get the image pixelated, but how do I get the disc/circle ...
0
votes
0answers
21 views

comments to a contributor of an answer [migrated]

How is it possible to alert a contributor of an answer of your post that you have answered to him ? In other words, to put his name in color in comments. I didn't find back the manipulation to this. ...
12
votes
2answers
1k views

NIntegrate error bound

I am trying to evaluate a highly oscillatory integral using NIntegrate. I fear that due to limited resources (time and/or memory), I will not be able to evaluate the integral to the desired precision. ...
0
votes
0answers
7 views

Linear vs. bilinear [migrated]

I'm tripping over something elementary: Suppose $f:\mathbb{R^2}\rightarrow X$ is linear, then $f(x+y)=f(x)+f(y)$ for all vectors $x$ and $y$. Now suppose that $f$ is also bilinear and in particular ...
0
votes
1answer
52 views

Plotting a function based on complicated integral

I have this function : f[Lambda_] := K Integrate[x Exp[- x^2-Lambda x] HypergeometricU[-Lambda,1/2,(x+ Lambda/2+2)^2],{x,0,Infinity}]; where ...
8
votes
1answer
72 views

UnitaryMatrixQ function not returning true for a unitary matrix

So I know this matrix is unitary. It's a well proven fact in quantum mechanics and you can even check for yourself on pen and paper, Heres a quick proof: Assume $H$ is hermitian (i.e. $H^\dagger=H$) ...
0
votes
1answer
45 views

Off[FinancialData::notent] fails on first run but works thereafter

Off[FinancialData::notent] fails on first run but works thereafter. So what good is it in this case? Is there a trick to force first time success? I've tried ...
18
votes
0answers
146 views

Why does Mathematica report that $\int_1^\infty\frac{\sin(\sqrt{x})}{\sqrt{x}}dx$ = $2\cos(1)$?

Mathematica 10 gives the following very odd result, Integrate[Sin[Sqrt[x]]/Sqrt[x], {x, 1, ∞}] (* 2 Cos[1] *) which seems unintuitive. The integrand has an easy ...
5
votes
1answer
5k views

What does “Tag Integer is Protected” message mean?

(Newbie question) For every function I define I get this message: When I close and reopen Mathematica, and re-enter the function definition, I don't get the message anymore. What does it mean?
3
votes
1answer
51 views

Densityplot: isolines

I'm plotting a densityplot map from interpolated data. I need to draw lines in which the value of my function is constant (isolines), but to be constant is not the function itself but a manipulation: ...
18
votes
2answers
5k views

Can Reduce *really* not solve for x here?

Sometimes I get the feeling I'm just flailing blindly with Mathematica. Is solving for $x$ in the equation $$ \frac{\cosh (x/2)}{x} = \sqrt{2} $$ really beyond the scope of Mathematica? I try to ...
9
votes
1answer
759 views

Why is this 2D plot so slow?

I first do a 3D Plot of four surfaces (eigenvalues of a $4\times4$ matrix) over $kx,kz$ (setting $ky=0$ all along). And then I try to give a 2D plot along three connected particular lines in ...
19
votes
2answers
4k views

How do I work with Root objects?

I want to solve the trigonometric equation : $$(3-\cos 4x )\cdot (\sin x - \cos x ) = 2.$$ I tried Solve[(3 - Cos[4*x])*(Sin[x] - Cos[x]) == 2, x] It returns the ...
3
votes
4answers
179 views

ParametricPlot3D for only part of a sphere

I want to plot the region of a sphere that satisfies the equation $$ \tan\theta\geq-\frac{z}{x\cos\phi + y\sin\phi} $$ where $x$, $y$, $z$ are my parameters. The spherical coordinates $\theta$ and ...
6
votes
2answers
162 views

How to draw a family of planes and its envelope?

Motivated by a question in MSE, I have the following question: How can I visualize the envelope of the family of planes $$ 2ax+2by-z+a^2+b^2=0, a,b\in\Bbb{R} $$ which is given by the ...
37
votes
4answers
2k views

Compiling more functions that don't call MainEvaluate

I would like to use Compile with functions defined outside Compile. For example if I have the two basic functions ...
0
votes
0answers
43 views

Definite integral evaluation

I want to evaluate the following integral: g[T_] := Integrate[(x^4*Exp[x])/((((A*(x^4) (T^4) a^4)) + (v/L) + (R*T*x)) (((Exp[x] - 1)^2))), {x, 0, (d/T)}] ...
3
votes
2answers
813 views

video image recognition [closed]

Has anybody experience with video and image recognition? I've made a video of two teams playing soccer. Now I would like to translate each soccer-player to a (x,y) coordinate and follow them during ...
106
votes
12answers
5k views

What are some useful, undocumented Mathematica functions?

There have already been some questions about some undocumented functionality in Mathematica. Such as (please add to these lists!) How can one find undocumented options or option values in ...
2
votes
1answer
76 views

Error propagation code

I have a code for error propagation :- ...
7
votes
2answers
164 views

How can I get the solutions of $x^n-x-t=0$ in hypergeometric form?

$x^3-x-t=0$ has three roots that can be expressed in hypergeometric form $$x_1=-1-\frac{t}{2}{_2F_1\left(\frac{1}{3},\frac{2}{3};\frac{3}{2};\frac{27t^2}{4} \right)}+\frac{3t^2}{8} ...
2
votes
1answer
35 views

Reading an exported List

I have exported a list of 2d coordinates as a List: Export["F:\\coordinates.dat", coordinates, "List"]; You can access the ...
8
votes
0answers
75 views

Differential equations with rational functions as solution

I have some families of nonlinear, first order differential equations. When I try to use DSolve, I usually get a mess (if anything at all) in terms of ...
8
votes
2answers
188 views
2
votes
0answers
22 views

Can JLink return a structured object?

What I want to achieve seems obvious but I cannot figure it out: I need to find a way that when I send an expression to be evaluated from a Java back end to a Mathematica kernel, I can live with it ...
6
votes
2answers
188 views

Plotting a function with three real arguments using transparency

I would like to plot a real function with three real arguments by assigning a transparency and color to the function values. The smallest value in the plotting range should be fully transparent, the ...
6
votes
1answer
186 views

Rendering a 3D volume with Image3D

I have 2D JPEG images, of 1024 x 1024 pixels, corresponding to a 500 x 500 square micron section. These images are taken from slices of tissue, each slice seperated by 10 microns. I've been trying to ...
5
votes
2answers
64 views

Small World network on a square grid

My aim is to generate a 2D Small World network on a square grid. i.e. 20x20. With a probability of 5%, one node rewires from an adjacent node to a random node of the grid, allowing some long distance ...

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