0
votes
0answers
27 views

Obtaining parametric equations through curvature and torsion

I wish to solve for the curvature and torsion functions $k_1 = \dfrac{1}{1+s^2}, k_2 = \dfrac{s}{1+s^2}$ using the Frenet Serret system and obtain the parametric equations for the curve. I need the ...
3
votes
0answers
23 views

How to use URLFetch for a https secure automated login?

With Mathematica 10.3 on Windows 10 I want to use URLFetch to do a so called 'Non-interactive/Bot login' at Betfair. The Betfair API manual gives this example in Python: ...
1
vote
0answers
17 views

Getting CUDALink (Toolkit 7.5) to work on Linux, Mathematica 10.0.2, GTX750

I want to make use of some CUDA functionality on my machine. It is running Gentoo Linux (64bit), Mathematica 10.0.2 on an Intel Xeon E5-1620v3 with a Geforce GTX750. So everything on the hardware/OS ...
0
votes
0answers
40 views

Reproducing Mathematica's Nullspace basis within c++

Using the function NullSpace in Mathematica gives a basis that has very nice properties for my purposes; for example the vectors seem to be ordered with the last ...
8
votes
1answer
94 views

What governs images resizing in the FrontEnd environment

What is responsible for the middle Row images' size? And why single image row is different? ...
0
votes
0answers
32 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 'n'. How do I specify the system of equations? If I use Solve, I can solve a system ...
0
votes
1answer
52 views

How can I implement a moving standard deviation for a time series? [on hold]

I imported the following dataset and converted it into a time series. ...
-1
votes
0answers
49 views

What is the imperative (or pseudo) code for this mathematica code?

I know Mathematica to be a powerful tool and it is impressive how much you can pack into a one line of code. I would like to use the following line, which I don't understand completely, in an ...
0
votes
0answers
26 views

Suddenly error when training SVM

I am running Classify[] function using a SVM model, suddenly I get an amazing error that I can not resolve it here is my code. The data is imported from a file *.txt ...
0
votes
0answers
72 views

Defining a function after doing several calculations inside

These things are probably very well known but I am a bit confused. After spending a long time, I was able to perform an operation on a function. Let's call the function ...
3
votes
2answers
61 views

Setting WholeCellGroupOpener

When I write WholeCellGroupOpener, Mathematica autocompletes it, but it doesn't recognize it (it stays blue instead of turning black). Example: ...
3
votes
1answer
73 views

NDSolve for optimal control theory

For an optimal control problem, I need to solve a differential equation in which (a) the system is formulated according to a function and (b) initial/terminal conditions are discontinuous. Here is an ...
3
votes
1answer
75 views

How to reconstruct a given schematic picture from color image

There is a nice website on popular Economics with stylish picture. ...
0
votes
0answers
31 views

Selection of all the objects with the same style in a notebook [duplicate]

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 do it only cell by cell.
1
vote
1answer
28 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
60 views

Help on using Solve

I tried to use Solve to solve a set of nonlinear equations and got this error: Solve was unable to solve the system with inexact coefficients or the system ...
1
vote
0answers
73 views

NDSolve: Indeterminate expression 0. ComplexInfinity encountered?

The following code give errors that I don't understand. Could you please suggest a method to solve these differential equations? ...
0
votes
0answers
23 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. ...
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 ...
12
votes
4answers
600 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 ...
3
votes
1answer
58 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: ...
24
votes
0answers
221 views

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

Bug introduced in 7.0 or earlier and persisting through 10.3.1 or later Mathematica 10 gives the following very odd result, ...
2
votes
1answer
42 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 ...
4
votes
2answers
63 views

Specify range and reverse for colordata in contourplot

The following two examples work ...
1
vote
1answer
56 views

Double arrow in the outcome

Does anyone know how do I get rid of one of the double part at the start of the outcome rh-> rh-> ...
0
votes
0answers
42 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: ...
9
votes
1answer
833 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 ...
0
votes
1answer
48 views

Issue with replacement rules screwing up a matrix [on hold]

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 ...
3
votes
4answers
185 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 ...
0
votes
1answer
52 views

Applying a formula to the data in several files [duplicate]

I am calculating with the depth data recorded in a number of files with extension .log. The depth data is like this and I loaded it by means of Mathematica: ...
0
votes
1answer
54 views

Improper Integral Difficulty [on hold]

Trying to do the problem $$\int_0^{\infty}e^{-sx}\cosh(ax)\,dx.$$ where we have the assumption that $s>|a|$ and everything is a real number. We tried: ...
2
votes
0answers
44 views

Plotting a parametric function that is highly nonlinear

Okay, so I'm having some trouble with some very badly behaved functions. I'll try to phrase the question in general terms to begin with, because the actual equations consist of about 12 numerical ...
3
votes
1answer
56 views

Do Any of the filter functions perform a LOESS or LOWESS filter?

From the Data Transforms and Smoothing guide there is a link to the Linear and Nonlinear Filters guide. Do any of these filter functions perform a LOESS or LOWESS filter on set of paired data? ...
8
votes
0answers
80 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 ...
5
votes
2answers
67 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 ...
2
votes
1answer
36 views

How to trace back to the reasons of this GUIScreenShot's behaviour?

The question I'm going to pose is surely, in some extent, version dependent, however I conjecture that it's rooted in general aspects of video manager architecture in Windows. This, I believe, makes ...
0
votes
0answers
45 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)}] ...
0
votes
0answers
33 views

Mathematica won't evaluate expressions [on hold]

Mathematica isn't evaluating a lot of expressions for me, and I'm unsure of why. Input of GeoDistance[{37, -109}, {40.113, -88.261}] gives output of ...
1
vote
2answers
107 views

Symbolic expression for recursion

Is it possible to get symbolic expression for recursive function? In particular I am checking if a symbolic expression is possible (i.e. f[n]) for the following code: ...
3
votes
2answers
72 views

Rounded rectangle with color gradient

Basically I'd like to produce a graphic like this: That is a rectangle with rounded corners, filled with a color gradient. While Rectangle offers the ...
0
votes
0answers
22 views

DerivativeFilter[] is scaling down the data by ~100 or so, not a true differentiation?

I'm running the following function vzz = DerivativeFilter[z["Path"][[All, 2]], {1}]; But if I then integrate vzz the output z is about 100 smaller than the ...
8
votes
1answer
80 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. $H^\dagger=H$) ...
1
vote
1answer
35 views

How to visualize .data files? [on hold]

I am working with simulation models trying to carrying out some predictions in ocean waves and this stuff. (MITgcm) I am able to run the program and generate output .data files, but i don't know how ...
2
votes
0answers
24 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 ...
1
vote
0answers
28 views

How to Build a Tree of Titles in a Notebook? [duplicate]

I am new to Mathematica so I am sorry if the question is rudimentary. :) When I was reading the help page, I noticed that there is a structure like the picture below for the topics in the help page ...
1
vote
1answer
54 views

Partial differential equation with infinity limit

How do I get Mathematica to solve the following partial differential equation $$ \frac{\partial u(y,t)}{\partial t} = \nu \frac{\partial^2 u(y,t)}{\partial y^2}+\frac{\partial U_0(t)}{\partial t}$$ ...
2
votes
0answers
47 views

How to implement QLearning?

I know that v10 has support for both Machine Learning and Finite Markov Processes, the Q-learning algorithm uses both. Specifically, Q-learning finds an optimal action-selection policy for any given ...
0
votes
1answer
34 views

Call user defined function from many notebooks [duplicate]

I wanted to ask a simple question. I am new to Mathematica, and I don`t find a way to call user defined functions just as I call Mathematica functions. I want to use my own defined functions, but ...

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