1
vote
2answers
306 views

Fourier series for rectangular wave incorrect, why?

I'm trying to get the fourier series function(s) to work for a square wave with duty cycles other than 50% ie rectangular wave. ...
2
votes
3answers
400 views

Marking specific points on a 3D curve

Here is the curve below. (written as a position vector) r = {Cos[7 Pi*t], Cos[6.2*Pi*t], 2.5*t} ParametricPlot3D[r, {t, 0, 2}] I want to know how I can mark ...
8
votes
1answer
556 views

Control BarLegend size

I want to plot a big 2D array of experiment data. I need plot axes and tick labels as well as a bar legend using BarLegend: ...
0
votes
1answer
364 views

Finding all maxima and minima of a function

To find all (global and local) extrema of a function in R3 I have written: Example-function ...
2
votes
1answer
426 views

Solution given by Wolfram Alpha but not _Mathematica_

Why will Mathematica not give a soluion to Solve[Log[x] == Log[j, Log[j, x]], j], but Wolfram Alpha will?
0
votes
1answer
504 views

Obtaining the envelope of an oscillating function and perform fitting

There is an elegant way to obtain the envelope of an oscillation function explained here http://mathematica.stackexchange.com/a/27854/15966 My question is how to modify the code below so I can fit ...
2
votes
1answer
118 views

Trying to combine an image with a Plot

I've got this picture: The image has a resolution of 2001x2001. The left most pixel has an x-value of -2, and the right most pixel has an x-value of 2. Same goes for the y-values. Now I am trying ...
0
votes
0answers
46 views

Automatic Cuda/CPU code; Fast programme run [duplicate]

I have developed my thesis codes by means of Mathematica software in a .nb file format. Despite using the available Parallel code capabilities and doing all the numerical integrations by means of ...
0
votes
0answers
15 views

How can I set global computation options ($MaxPiecewiseCases) for parallel kernels? [duplicate]

I'm trying to do a calculation in parallel that requires setting $MaxPiecewiseCases. How can I do this? This small test case doesn't work for me: ...
4
votes
1answer
309 views

How to get better quality EPS graphics

Yesterday, I was doing any Tables of 15 graphs similar to the next example, to save .eps and use in latex. In the generation of the graphs Mathematica spends many time. Is possible to reduce this ...
2
votes
2answers
115 views

What is wrong with my use of Flatten? [duplicate]

Why does Flatten[f[g[a, f[b]], f[c, d]]] result in f[g[a, f[b]], c, d] I expected the answer to be ...
1
vote
4answers
142 views

Plot roots of B(z) according to angle small to large

I have the following function: B[z_]=((z*(z - 0.5)*(z + 0.5))/((1 - 0.5*z)*(1+0.5*z))) I want to plot the roots this polynomial according to angel like below ...
1
vote
0answers
124 views

How to construct a coordinate system that owns detailed calibration in the 3D enviroment?

Recently,I write a program to demonstrate the forward kinematics of the SCARA robot.The code showed as below: Using this function to construct the BigArm and ...
1
vote
1answer
82 views

Is this the expected behaviour from Partition when padding is inserted at the start of the list?

The documentation for Partition shows an example of partitioning without padding, so that no elements are dropped, but the last sublist can be shorter. ...
3
votes
2answers
113 views

Find Lists with intersecting sublists

I have a list of the following form: ...
0
votes
4answers
346 views

Plot graphs with ListPointPlot3D and different colours and size of points

Hello I am New in Mathematica. I have a set of points and I want to visualize in Wolfram Mathematica. I want to see big blue points and small green points in one picture. Big Blue points ...
1
vote
1answer
60 views

What domain does Resolve assume by default?

Consider the statement: $\forall x\left(x<7\Rightarrow \exists a\exists b\exists c(a^2+b^2+c^2=x)\right)$ This is true provided the universe of discourse is $\mathbb{N}$ Now I use ...
1
vote
2answers
194 views

Selecting parts of a matrix via indices given by a vector

I have a column vector of the form $\{1, 1, 2, 3, 2, 3\}^t$ and an associated matrix that has the same number of rows as the column vector, $6$, and a number of columns that is equal to the maximum of ...
0
votes
1answer
163 views

Inverse Laplace transform

For this expression: $ (1 - Exp[-Sqrt[1+s] x])/(1+s)$ How to make the Inverse Laplace Transform analytically? ...
1
vote
1answer
331 views

Is this function convex?

How can I determine convexity of the function f = Log[ x, 1 + (x^a - 1) (x^b - 1)/(x - 1)] with the parameters $a,\,b$ belonging to the interval $(0,1)$ in ...
8
votes
2answers
596 views

How to get UV mapping of 3D tube

Here is cylinder data: file We can mesh the surface, thanks to lalmei, Belisarius and Simon (link) How to achieve uv mapping from a 3d straight and curved tube? Working code: ...
0
votes
2answers
59 views

How to output (anything) if any error happens

I have long code which goes through iteration process. some times I get error messages. I want to get the iteration numbers (or any kind of output indications) when errors happen. for example, how ...
1
vote
1answer
95 views

Noninteger indices for tables

Is it bad programming practice to use non-integer values to label data tables? For example, ...
1
vote
2answers
560 views

How to make Mathematica use the chain rule?

Lets say I have the following PDE: $$x^2 u_{xx} - u_{yy} + u_y = 0$$ And I have the following change of variables: $$ s(x,y) = x e^y \, \, \, , \, \, t(x,y) = x e^{-y}$$ How can I use Mathematica ...
3
votes
3answers
244 views

Algorithm to generate a certain matrix

I am looking for a convenient way to generate a matrix of the following symmetric form (numbers could also run from -3 to +3 or just from -1 to +1): Tips, anybody?
25
votes
3answers
1k views

Smooth Peter de Jong attractor

Today I was playing with Peter de Jong attractor. At the bottom of the page I've linked there are beautiful examples like: My attempts are not so great: It is around 10^5 points. For more than ...
1
vote
2answers
283 views

On Parameter Estimation using FindDistributionParameters

I am a novice of Mathematica and have recently started my self-study of maximum likelihood estimation (MLE) using Mathematica. I would like to estimate the parameters associated with a distribution ...
1
vote
2answers
93 views

Numbering of cases implied by a subset of Boolean vectors

In the course of a programming problem I stumbled upon the following sub-problem. Given an arbitrary, but fixed, number of Boolean variables, I would like to be able to pick a subset of the ...
6
votes
3answers
481 views

RK4 Gravity Simulator

I have the following RK4 solver which splits the two 2nd order ODEs, used to calculate x and y positions under the influence of a gravitating body where $$x''(t)=\frac{G m ...
5
votes
1answer
784 views

Is there a free version of the Springer book “Mathematical Statistics with Mathematica”?

Is there a free version of the Springer book: $$\text{Mathematical Statistics with Mathematica}$$ by Rose and Smith ... available on the internet?
2
votes
1answer
290 views

Euler's method for a 2nd order ODE

This is my first post on this site. Also, I'm new to Mathematica. I'm trying to solve my first problem with Mathematica. It's about solving a 2nd order differential equation. I dont have the explicit ...
2
votes
1answer
195 views

Moment central of a binary image

I am implementing the Hu set of invariant moments detailed here Hu set of invariant moments. I implemented the moment Image like this: ...
0
votes
1answer
117 views

shade plane with a color function color(x,y)

I am making a RGB color function which assigns an RGB color to each point in the plane. To check if it does what I think it should do (i.e. debugging it), it is helpful to be able to plot the function ...
0
votes
2answers
171 views

Simplifying an expression containing radicals

Now I'm trying to use Mathematica to simplify an expression like this: $P \sqrt{-P + \sqrt{M^2 + P^2}} + \sqrt{(M^2 + P^2) (-P + \sqrt{M^2 + P^2})} - M \sqrt{P + \sqrt{M^2 + P^2}}$ where ...
2
votes
3answers
123 views

Extract memoized results in the form of a rule

Lets say I define a function f with memoization. Is there some way to extract the memoized values? For example, ...
2
votes
2answers
122 views

Rounding only coefficients

does Mathematica have built in functionality to round the coefficients of a polynomial to a certain accuracy. Say, we do Print[0.2134320980x^2+0.0023432x] Can ...
0
votes
1answer
281 views

How to open Mathematica from the terminal in OS X

So far, when I was working in Linux, I would open my Mathematica files from the terminal by typing: mathematica filename.nb & But now, I got a mac, and when ...
0
votes
3answers
172 views

Why does Maximize return a wrong answer?

I want to find the maximum of the following function, but get a wrong result. What am I doing wrong? ...
1
vote
2answers
156 views

How to plot partial derivative of an integral vs. another variable?

Just to take an example, because my original numerical integral was too complex: T[t_] = NIntegrate[Exp[(eta - 1)*t], {eta, 0, 4}] But when I am using ...
0
votes
3answers
163 views

Automatically evaluate next cell

I am new to Mathematica. I am trying to achieve the following: I need one input cell in which I set parameters, then another input cell where functions are defined and calculations are performed. ...
17
votes
3answers
849 views

How can I list all the 'countries 4000 km far from current location'?

A friend said to me on Facebook that she is 4000km away. So I want to try to guess where she is. How can I find which countries are a given distance from my current location?
1
vote
1answer
136 views

Check every list element for appearance

I'm used to MATLAB so this might be a stupid question but Mathematica is freaking me out. I have a big matrix with the following format: ...
1
vote
1answer
115 views

Open parent cell groups of selected cell

I wrote a small script for a palette, which allows me to highlight a specific cell in a notebook by using SelectionMove[mycell, All, Cell]. The cell is selected as ...
1
vote
1answer
112 views

How can I make a ContourPlot3D with inequality constraints?

I need to plot a function in implicit form as below: ...
8
votes
1answer
834 views

Schrödinger eigenvalue problem in two dimensions (Harmonic Oscillator)

I read here the discussion about how to solve a one-dimensional eigenvalue problem. I am wondering, how can one generalize these methods to two dimensions? For example: ...
4
votes
1answer
156 views

Importing malformed XML: Import[… “XMLObject”] vs ImportString[…, “XML”]

It appears that Import[ url , "XMLObject" ] is more forgiving of improperly formatted XML than ImportString[ string, "XML"]. For ...
3
votes
2answers
137 views

Labeling vertices by number in Graph: Getting text to display at the right size

Minor aesthetic question here. I was playing around with Graph's and decided to render a cute-looking family of directed graphs, with the vertices being the number ...
-1
votes
2answers
176 views

Solving partial differential equation with DSolve does not give a result [closed]

I am trying to solve the equation: $-(d^2/dx^2+d^2/dy^2)\psi+(x^2+y^2-2)\psi=0$ Here, is my code: ...
3
votes
1answer
154 views

RegionPlot3D and Texture

I'm getting a white solid instead of a solid with texture, I'm not sure what is wrong: ...
5
votes
1answer
254 views

Can I automatically stop operation that is too slow?

I need to write code like this: Do operation 1, but if it takes more that 5 seconds then stop it and do operation 2. Is it possible to do this somehow without manual interruption?

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