0
votes
1answer
7 views

Is the MaximalBy function still used

On the mathematica reference website it gives examples using the MaximalBy function, However when I am using it, I see no desired output. This leads me to wonder if mathematica has stopped using this ...
0
votes
2answers
22 views

Plot a one-dimensional list of numbers as a column/row of labeled colored squares?

I have a list of numbers, and a matching list of labels. I want to plot a column of colored squares, with the color of each square matching (in some color scale) the value of the corresponding number. ...
0
votes
1answer
75 views

Plotting Time Series with call to Wolfram Alpha

I am trying to plot stocks showing some of the local maxima. As an exercise I first tried to load Apple's stock data from Wolfram Alpha with the following code: ...
3
votes
0answers
18 views

Operator and VariationalMethods

I'm trying to get the variational derivative $\delta E$ respect to $\Phi$ of this functional $$ E[\Phi] = \int d^3r\ \left[ -\frac{\hbar^2}{2m}\nabla^2\Phi + V(\vec{r})\Phi^*\Phi + ...
1
vote
1answer
60 views

Numerical error in Mathieu functions

Consider the MathieuCharacteristicA function, which is a piecewise function according to the documentation. The discontinuity happens at integer number. ...
0
votes
1answer
160 views

Defining a new matrix product of matrix function

Suppose I have two matrices A, B, whose entries are functions of x. Suppose they are 2*2. In the product, each entry is of the form $\sum_k A_ik B_kj$. There are two summands corresponding to k=1,k=2. ...
0
votes
0answers
6 views

Probability in a knock-out tournament [migrated]

Maths newbie so please go gently. Imagine if you would: 4 teams in the semi-final of a soccer tournament A,B,C,D. A,B and C all have 20% chance of winning the tournament. D however, is the favourite ...
1
vote
3answers
54 views

Alternatives to Append/AppendTo for generating a list in an interactive DynamicModule?

I have a stack of timelapse microscopy images that I am trying to segment frame-by-frame using some of Mathematica's image processing functions. I have created a little interactive DynamicModule with ...
0
votes
1answer
49 views

Is it possible to build/simulate/extract data from a System Modeler model completely inside a notebook using the MathModelica language syntax?

See examples in: http://www.mathematica-journal.com/issue/v10i1/contents/MathModelicaPaper/MathModelicaPaper_2.html It seems to be ruled out by the statement (Chapter 2 intro): "The subset of the ...
0
votes
0answers
28 views

On the order of rules specification

I wanted to understand how Mathematica parses function definitions in rules-based programming, so I started with the simple code: ...
7
votes
1answer
278 views

Color ramp banding in PDFKit when exporting Raster image Inset to PDF

Here I produce a Raster image with large uniformly colored rectangles and put it in an Inset: ...
4
votes
1answer
101 views

Format-Size-Larger/Smaller shortcut disabled in M10?

It seems that the keyboard shortcuts for enlarging/reducing the font size (ALT+= / ALT+-) don't work anymore in M10 as it did in M9. If I select the text (or code) inside a cell they work. But if I ...
2
votes
2answers
51 views

Local variables whose definitions depend on each other [duplicate]

Consider the following (pseudo-)function definition: f[l_] := Let[{ a = Length[l], b = First[l], c = b/a, }, c*10] So for ...
0
votes
0answers
19 views

Hypergeometric Function of Matrix Argument

I am looking for the evaluation of a Hypergeometric function with a matrix argument as for example in Ploev and Edelman: http://math.mit.edu/~plamen/files/hyper.pdf or as showcased in the Wikipedia ...
5
votes
1answer
48 views

ListPolarPlot: 0 Degree at vertical axis

Is it possible to have ListPolarPlot start plotting at the vertical axis? By Default ListPolarPlot gives this result: ...
19
votes
2answers
225 views

Object separation from a 2.5D surface

I'm trying to identify the shape and the boundaries of objects. The data was generated with a laser scanner and represent the surface of an area in which many boulders lay on the ground and making up ...
6
votes
2answers
94 views

Export MatrixPlot graphics to PDF

I am trying to export a plot generated by MatrixPlot to PDF but am having problems with the way the exported PDF is rendered. ...
2
votes
1answer
20 views

ExportString and HTML: where are saved images?

I want to use ExportString to generate HTML expression. Here is an easy example: ExportString[x^3, "HTML", "FullDocument" -> False] gives ...
1
vote
0answers
50 views

Interpolating function into an actual function

I numerically solved an integral equation and the result is an InterpolatingFunction. I plotted it to see how the function behaves but I also need an actual ...
5
votes
2answers
90 views

Numerical value of physical constants Mathematica 10

Is there a way to use the physical constants in calculations and have Mathematica 10 figure out the final unit and numerical magnitude? When I try ...
2
votes
0answers
80 views

Power::infy: error using FindFit

I have a 2D data to fit (the Airy type pattern from diffraction of Gaussian beam on the circular aperture). Please see the attached picture. I was going to use a function like ...
0
votes
1answer
72 views

Specifying initial conditions for a PDE

I have simple diffusion equation with point source at c(0, t) = 1 and initial condition c(elsewhere, 0) = 0. How should I apply ...
3
votes
2answers
38 views

Filling dependence on order of points in ListPlot

ListPlot[{{{1, 0}, {0, 0.5}}, {{1, 1}, {0, 1}}}, Filling -> {1 -> {2}}, FillingStyle -> LightGray, Joined -> True, Frame -> True] Results in no ...
17
votes
0answers
376 views
+50

Proving the hairy ball theorem using xAct

I would like to formally prove the hairy ball theorem in Mathematica, initially just for $S^2$, and then see about generalizing. An approach I thought about to use the xAct package to define $S^2$ ...
2
votes
0answers
35 views

Some global variables are defined even at the start of a fresh session

In a fresh Mathematica session evaluating Names["Global`*"] doesn't give an empty list. The result is either {rhs, z} ...
4
votes
2answers
44 views

Problem with general assumptions

I hope I am not to redundant with my questions. As part of solving a physical problem, I want to assume once and for all that all my variables and parameters are real, positive and finite. Is it ...
0
votes
0answers
16 views

How to deal with matrices involved in system of SDEs?

This question is in continuation of the the previous posts enter link description here and enter link description here. What I want to do is numerically solving the epidemic model which can be defined ...
9
votes
8answers
387 views

UnFlatten an array into a ragged matrix

Trying to unflatten an array that was part of ragged array of sub matrices. As input we have flattened array: ...
10
votes
5answers
345 views

Plot the plane so different condition has a different color

I have a list of functions defined on the plane, and I want to know which one of those functions is smaller than the other functions at particular points. Currently, what I do is ...
3
votes
3answers
95 views

Transformation of Derivatives under change of coordinates [duplicate]

I have an expression depending on the two variables z and t, and the derivative of a known function $f(t,z)$. Something like: $$myexp \ =\ t\ z\ \partial_z\ f(t,z)$$ Now I want to make a change of ...
3
votes
1answer
63 views

What is the order of execution of Animate?

I used to think the execution order of Animate is the same as For until I find: ...
4
votes
0answers
98 views

Menu commands on Palettes and other windows without menu bars?

In the Version 10 interface, at least by default, there is no longer a common menu bar in a separate window, and menus appear to be localized to individual Notebook windows. If I select a Palette and ...
6
votes
5answers
266 views

Find patterns in a list

again, I have a list like this: ...
2
votes
0answers
29 views

Efficient processing of Special Ordered Sets with LinearProgramming

I'm playing with integer linear programming, especially problems involving lots of constraints which would appear to be special ordered sets. Below is a toy example, three last rows of the matrix ...
1
vote
2answers
145 views

Permutations with restrictions

I have a problem that can be modeled as: there are 8 boxes in total, and 60 different items. I want to put all items into boxes (all of them can be put into a single box). Now I want to find: 1) ...
7
votes
5answers
288 views

What is my problem with MeshFunction?

I want plot the max value in a sine plot. We can use the following code ...
6
votes
2answers
49 views

Recursive function with array of variables

I am trying to create a recursive function which works with an increasing array of variables. Since the formula is quite complex, i will try to simplify my example to the core of my problem. The ...
6
votes
1answer
217 views

Tuples without self-loop

I have a simple question coincerning the Mathematica function Tuple. Currently, I apply the following code ...
1
vote
2answers
75 views

Enabling/disabling individual locators within a Manipulate

This post helped me out somewhat but it is missing a piece that I really need for something that I am working on that's more complex than what I've shown below. I want to disable a ...
3
votes
2answers
122 views

Selectively updating individual graphics in a dynamic, multiple-plot Show

Suppose Show contains multiple graphics objects that differ markedly in the amount of computation needed for their display. Hence, when dynamically updating only ...
10
votes
3answers
78 views

How to limit number of user-defined messages issued per evaluation

I have written code such that if it runs into a particular function, a warning message is issued. However, it is common for the program to call this function several times in a single evaluation, but ...
2
votes
1answer
362 views

How to create these famous surfaces in topology with the desired color effects?

It was said such real objects of famous topological surfaces were plotted by the cooperation between mathematician Richard Palais and artist Luc Benard, and published as the cover page of Science ...
0
votes
1answer
51 views

NDSolveValue producing message: Input is not an ordinary differential equation

I have an urgent question for my program because I get always an error output for it. I have a partial differential equation that I want to solve with NDSolveValue. ...
1
vote
2answers
1k views

Tricks for solving (lots of) coupled nonlinear equations numerically?

I have a system of 6 non-linear (quadratic) coupled equations with 6 complex unknowns \begin{align*} |x_1|^2 + |x_2|^2 + |x_3|^2 &= a\\ x_1 x_4^* + x_3 x_5^* &= b + c i\\ x_1 ...
0
votes
0answers
50 views

What is the meaning of a result of {{}}? [on hold]

What does an output of {{}} mean in Mathematica after solving a system such as: $e^{x}=e^{x}$ for $x$?
2
votes
0answers
62 views

How to solve three equations with four unknowns iteratively?

I have three equations of the form $\quad \eta = f(N1L, N2L)$ $\quad N1L = g(\eta, R)$ $\quad N2L = h(\eta, R)$ I want to eliminate $\eta$, so that I can get $N1L$ and $N2L$ for a range of $R$. I ...
0
votes
0answers
42 views

Extract the minimum positive root from a quintic [on hold]

I need to compute the values of ϵϵ and x2 from the following sytem: ...
1
vote
2answers
89 views

How to do a region plot with many functions [duplicate]

Hello i am trying to compare many function, i want to see witch one as the lowest value depending on 2 variables. My solution so far is something like this: I have 7 function: P1 P2 P3 P4 P5 P6 P7, ...
10
votes
2answers
276 views

Find maximum value of interpolation function - obviously wrong result

Minimizing and maximizing interpolation function has already been asked and answered, see here for example. Yet, I observe a strange behaviour. Well, I can understand that the wrong guess of ...

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