7
votes
3answers
446 views

How do I avoid scoping collisions of iterator variables?

Yesterday I had an issue that kept for quite a while. My code wasn't producing the right results. Now I know why and I am wondering how to avoid the issue in future. Consider the following code. ...
3
votes
1answer
109 views

How could I find the singular solutions of an ODE?

Starting with the equation $$y^{\prime\prime}x^2={y^\prime}^2$$ I could only get the general solution using DSolve: ...
3
votes
2answers
350 views

How can you combine lines in $\LaTeX$ and lines in Mathematica?

Suppose that you want to make a report about the golden section algorithm, and you want to explain the process with text in $\LaTeX$, and in every iteration you want to show in that report the values ...
5
votes
4answers
2k views

How can I format a table to look nice?

I have this code, but i would like to see the results well formated, How can I obtain a well formatted data with aligment?, similar to this one insted what i obatin, you can see here Here is ...
0
votes
1answer
82 views

Question about rendering axes [duplicate]

I have data points for a circle and would like to plot it with Mathematica. ...
7
votes
2answers
4k views

Solving a system of ODEs with the Runge-Kutta method

I´m trying to solve a system of ODEs using a fourth-order Runge-Kutta method. I have to recreate certain results to obtain my degree. But I'm a beginner at Mathematica programming and with the ...
5
votes
2answers
539 views

Mapping higher dimensions to color, opacity, point size, etc

I have a set of points of dimension >3, and I'd like to modify ListPointPlot3D so that the higher dimensions are mapped to different variables, such as color, opacity, point size, etc. so for example ...
4
votes
1answer
104 views

Why doesn't my line match my barchart?

I'm trying to create a chart that has both a line and a bar chart representation of an expression. Because I'm using the same expression twice, I expect the line and the bar chart to match, but they ...
3
votes
0answers
383 views

Is it possible to marginalize one or several parameters obtained from fitting procedure?

Statistical model analysis package has a few fitting functions. Their arguments are data points, fitting model and parameters in the fit. The result is a set of best values for parameters, which ...
8
votes
2answers
435 views

Combining Two Plots to Create a Zoomed Callout

I want to combine two images to create a zoomed callout, as illustrated below. The plot on the right is the zoomed in version of the boxed area on the left. The dotted lines connect the ...
5
votes
3answers
722 views

Solving a system of equations with conditions related to the number of solutions

The equation below describes a conic with oblique axis: $$9 + 22 x + 9 x^2 + 46 y + 24 x y + 16 y^2=0$$ It is a parabola, as the coefficients in $x^2$, $y^2$, $xy$ form a perfect square. To find the ...
12
votes
6answers
1k views

Determine the Number of Lines in a Text File

I have looked and looked but I do not see a simple efficient way to get MMA to return the number of lines in a text file? I thought about reading the file until it returned the EOF marker, but that ...
3
votes
1answer
136 views

Find point at which equation stops having roots (if it exists)

I am interested in the roots of this function: f[M_, b_] := 1 - (2 M Gamma[2, 0, (1/M + b M)/Sqrt[b]])/(1/M + b M) for fixed values of b. In particular I want ...
0
votes
1answer
627 views

Colorbar doesn't appear

I have a list of data with dimensions $(2000,4)$. I plotted it using ListPointPlot3D, setting the fourth dimension as the color. As follows: ...
3
votes
0answers
473 views

Solving recursion relations using Mathematica

I want to solve the recursion relation given in equation 2.7(a/b) on page $6$ of this paper. (..the initial seed is $F_1 = G_1 = 1$ and the functions $\alpha$ and $\beta$ are defined on page $5$ in ...
1
vote
1answer
326 views

Opening multiple kernels in command line for batch operation

I have been searching around for a while, and perhaps I'm just using the wrong terminology, but I haven't found a way to do this. I have a mathematica notebook converted and saved as nobel_test.m, ...
0
votes
1answer
643 views

Keeping axes fixed in an Animate of a 3D graphic

I am using the following code to animate a 20 3D ListPointPlots: ...
2
votes
2answers
663 views

How to remove a singularity with WhenEvent

Bellow I have a differential equation which hits a singularity at low values of t. What I want to do is somehow utilize the WhenEvent command in order to replace ...
0
votes
1answer
456 views

Avoid trigonometric simplifications?

When evaluating the expression Sinh[x]^2 + Cosh[x]^2 // FullSimplify I get Cosh[2 x] That is indeed a simplification, but ...
0
votes
0answers
224 views

Finding all roots of the system of two complex equations

I need to find all roots for the system of two complex equations. Obviously I can rewrite them as 4 real however problem remains. I have looked through routines connected with using ContourPlot ...
6
votes
1answer
207 views

Style of Slideshow

So I am giving my first shot at making a Mma slideshow. But I am finding difficult to change the formatting of Sections and others in the slideshow. I can change the style of Sections in the Working ...
-4
votes
1answer
228 views

Problem with interpolation

I have a problem with the function interpolation. when I use it my points are all very shifted. Do you have an idea of the solution? ...
13
votes
3answers
1k views

Font sizes in graphics

I'm trying to find an explanation for the different sizes I'm seeing for fonts added to graphics in different ways, and haven't yet located an easy to understand explanation. Here's a minimal ...
0
votes
0answers
22 views

Conflict among Permutations and Graph utilities once Combinatorica is loaded [duplicate]

I have tried to figure out and solve the problem of compatibility of Permutations and Graph utilities of Mathematica once the Combinatorica Package is loaded, but I failed :(. Could anyone explain me ...
0
votes
1answer
106 views

Plotting query - same values on Y-axis / viewing data

I'm new to Mathematica, and have numerically solved two similar functions with the following code; ...
3
votes
3answers
106 views

How to use Show in case one of the graphics doesn't exist?

I tried to combine three and more graphics with the Show command; but sometimes there is no data, so some of the graphics are empty lists. I tried this: ...
12
votes
3answers
540 views

Simulate a simple spinner

I'm teaching some simple ideas in probability to students in grade 7. The "spinner" below works, but I'm wondering how I could make it just a bit more realistic by having it actually "spin" around a ...
13
votes
1answer
336 views

I can't use PatternSequence with Cases

I have a list of integers: s = {4, 5, 5, 6, 2, 5, 3, 2, 4, 2, 1, 1, 4, 3, 4, 3, 1, 6, 3, 4}; And if I do this, both occurrences of 4 after 3 are replaced. ...
0
votes
2answers
322 views

characteristic polynomial based on differential equation

I have this differential equation: $$\ddot{x}-\frac{1}{6} \dot{x} - \frac{1}{6}x = e^t$$ When I DSolve it looks like this: ...
3
votes
0answers
136 views

Rule transformations for compositions of tensor products [closed]

The tensor product satisfies far commutativity: $(f \circ g) \otimes (h \circ k) =(f \otimes h) \circ (g \otimes k)$. I have some replacement rules I'd like to apply to an expression containing ...
24
votes
3answers
2k views

How to find the center of a circular pattern?

I am writing an algorithm that finds the center of 500 x 500 pixels images coming from a live feed from a camera at 50 Hz. So it has to be quick! The images are images of an optical field which looks ...
2
votes
1answer
247 views

Simplify expression to Abs

FullSimplify[Sqrt[1/(a^2 b^2)], Element[{a, b}, Reals]] gives Abs[1/(a b)] How do I simplify the following expression ...
1
vote
1answer
497 views

Method used by FindFit

Using FindFit, Mathematica selects an optimal algorithm when Automatic is selected. I'd like to know the name of the method ...
4
votes
1answer
503 views

How to get confidence bands of parameters from a fitting procedure?

I have done fitting of data points with a given model that has two parameters (A and B), using NonlinearModelFit. The result of the fit is the maximum of the ...
2
votes
3answers
528 views

Why doesn't Mathematica plot $n(-1)^n$ with Plot?

I was in doubt if this question should be asked in Mathematics.SE or Mathematica.SE, but I've decided this site would be more appropriate, because I think those who read my question here will know ...
4
votes
1answer
190 views

Access curated or locally stored data with curated data functions?

Say I have a toy package, something like: ...
3
votes
1answer
1k views

Accessing Twitter API using Mathematica [duplicate]

How do interact with the Twitter API using Mathematica? SocialMediaData is a lovely function, but appears to be severely limited in what it can draw from Twitter. For example, if I want to get a list ...
2
votes
2answers
676 views

How to expand a general expression in cross and dot product in Mathematica

I am looking for a way to simply the general expression in cross product and dot product with general vectors. I got a help in How do I simplify a vector expression? but soon I find that it doesn't ...
2
votes
2answers
138 views

changing a symbol into a function variable

Struggled for a while on this problem and hopefully you can help... I have a mathematical expression that currently has a symbol where I used to have a function variable. How do I make the symbol ...
-1
votes
1answer
118 views

Sorting the element in a PDB text file

I am a new user of Mathematica and currently using version 9. I want to rearrange the element of one PDB text file with respect to another PDB text file. Suppose I have a PDB file like this: ...
2
votes
1answer
426 views

NDSolve complains about missing derivatives of dependent variables in Mathematica 9

In Mathematica 8 NDSolve[{x[t] == 1, x[0] == 1}, x[t], {t, 0, 10}] solves fine and returns ...
1
vote
2answers
241 views

build and estimate a time series process

I want to generate an EGARCH process. My problem is that I do not see how to create new processes beyond those available. The process itself is : $$\epsilon(t) = \sigma(t) \eta(t)$$ ...
1
vote
3answers
268 views

Minimize user defined function

I have a user defined function h[i_,j_] and I would like to find its minimum value over all integers $1 \leq i \leq 100$ and $1 \leq j \leq 100$ and $j \leq i$. I would just like Mathematica to try ...
17
votes
2answers
1k views

Fastest way to measure Hamming distance of integers

I am looking for a fast and robust way to calculate the Hamming distance of integers. The Hamming distance of two integers is the number of matching bits in their binary representations. I expect that ...
6
votes
2answers
370 views

How can I find if the number of subsets for a list is very large?

I'm trying to find the following; Subsets[Range[2, 2300], {4}] but my computer gave the following error: ...
10
votes
1answer
317 views

Why does Mathematica fail to series expand this simple expression?

I wanted to expand the function $(x+2)^{x+2}$ around $x = -1$, that is, using Series[(x + 2)^(x + 2), {x, -1, 2}] and Mathematica returns the same expression. ...
1
vote
0answers
37 views

How to implement a set method? [duplicate]

I'm trying to program using object orientation in Mathematica. For this i need to implement get and set methods. Lets consider that we are working with a person class, that have the fields name and ...
4
votes
1answer
176 views

How can I monitor and detect when a website has changed?

I'd like to detect when a website has changed, in particular when new products are announced on a site that doesn't change to often. Here's the code I wrote but I don't think it is perfect. Also the ...
29
votes
1answer
570 views

How can I make threading more flexible?

Threading automatically with Listable functions requires the argument expressions to have the same length (or for one of them to be atomic). For nested lists the ...
6
votes
0answers
111 views

Design considerations behind `O` (a.k.a. BigOh, a.k.a. Landau Order)

This works without any warnings: O[Log[x]]. This raises a warning: O[x^2]. I have a few questions around this: Why is it a ...

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