3
votes
0answers
98 views

Optimizing a bubble art code [duplicate]

Based on that website I wanted to recreate the same effect using Mathematica but with any picture given by the user. Thus I came up with the following code: ...
3
votes
3answers
514 views

For-loop not working as I expect

I want to do this: When 10 <= t < 130, give t -> 1; When 130 <= t<300, give ...
15
votes
2answers
698 views

Extracting angles from a simple picture

I'm not sure if this is even possible with Mathematica, but I want to extract the angles between all lines in this picture: It consists of $12$ lines, so I want a matrix with $144$ entries. I ...
6
votes
4answers
514 views

FindInstance (and Solve, …) abysmally slow on a fully determined system of linear equations and inequalities: why?

I took a quick look for FindInstance and Solve-related questions but came up empty for the aspect that I am curious about. So ...
0
votes
1answer
139 views

Holding Input Windows

I am creating a Mathematica document which contains a list of proofs in various fields of Mathematics so that I can easily review whenever I would like. First, I create a large set I call 'proofs' ...
5
votes
3answers
1k views

cross-correlation with time lag

I have two lists with some data. a={1,2,3,4,5} b={5,4,3,2,1} Now I want to compute the cross correlation of the two lists with a time lag of 1, like it is ...
-6
votes
1answer
148 views

Alternative closed forms for digamma expressions

What commands should I use such that Mathematica / W|A express $$\psi(1+i)+\psi(1-i)$$ exclusively in terms of trigonometric functions?
0
votes
0answers
105 views

Exponential function Integral

I have tried to solve this integral: Integrate[E^(-((a^2 b c^2)/(a^2 + b)))/(a^2 + b)^2,a] Mathemathica is not able to solve it, I have tried the integration by ...
2
votes
1answer
123 views

NDSolve with different function lengths over time

I'm working on a cops & robbers game, and there is one single event that is very very important, the event of catching someone. I'm trying to do when any robber is catched, delete it from the ...
1
vote
1answer
97 views

Why TensorReduce not working here?

I would like to use TensorReduce to work on the tensor contraction $y_{ib}y_{ia}$ (where index $i$ is summed). However, ...
3
votes
1answer
165 views

How to vary thickness of line on the plot? [duplicate]

How to plot the function f(x) so that one part be a thicker line than another depending on the value x? (Curve is efficient frontier - portfolio optimization)
2
votes
2answers
111 views

Return only one numeric solution to equation [duplicate]

Consider a simple plane equation 2x-3y+4z==7 I just want some position vector on that plane. For example, {7/2,0,0} would be ...
3
votes
3answers
441 views

Is Mathematica compatible with primusrun?

I use Mathematica 9 on Ubuntu 12.04 LTS x86 (64-bit). My computer has an Nvidia graphics card, for which I installed primus and ...
0
votes
0answers
78 views

densityplot + world map overlay [duplicate]

I can make a world map, and I can make a density plot, but I can't seem to get them to overlay. Was trying to use Show to overlay: ...
3
votes
2answers
149 views

Exploiting a relation among constants

Say I have two arbitrary real constants $p,q$ that satisfy $p^2+q^2=1$. Is there any way to easily declare this relation in Mathematica? Edit More specifically I have this (among others) expression: ...
0
votes
2answers
135 views

Handling output that was returned unevaluated from a function

When evaluating functions, including those described in this post, how do Mathematica users handle values returned from a function that are unevaluated? For example (based on 1): ...
4
votes
1answer
194 views

What is the correct way to provide Mathematica with a path to Python user scripts?

What is the correct way to provide Mathematica with a path to Python user scripts? Simply executing Python as a shell command, using something like ...
0
votes
1answer
120 views

Binomial sum identities

How do you persuade Mathematica to give simple identities involving binomial sums. For example Sum[Binomial[a,i]*Binomial[b,i],{i,0,n}] where n is bigger than ...
5
votes
1answer
102 views

Clean webMathematica Kernel

On my webMathematica server, certain input values are being saved between page loads on different computers. I assume this is because the kernel is not clearing the values after it finishes loading a ...
9
votes
1answer
319 views

Is there a way to see the result of NIntegrate's symbolic preprocessing?

NIntegrate can do a number of different types of symbolic preprocessing on the integrand before starting the numerical calculations, including changes of variables. ...
0
votes
1answer
94 views

How to show an exclusion limit [duplicate]

I would like to show an exclusion plot, by having a filling made of parallel tilted lines. Any ideas? Something along these lines
5
votes
1answer
174 views

How to impose control over vertex-to-vertex Graph edges?

I’m working on a Markov Chain and hope there is a way to impose control over how Mathematica places edges to connect vertices in a Graph. My Markov Chain currently consists of 4 vertices with 2 of the ...
15
votes
0answers
201 views

Graphics`Mesh`FindIntersections[ ] fails to detect intersections

Graphics`Mesh`FindIntersections[ ] is an undocumented function for, well, detecting intersections very efficiently. Take a look: ...
1
vote
2answers
420 views

Mapping functions over multiple lists

I am not sure if this is a duplicate. Spent some time looking over list-manip questions. I’d like to know the Quickest Way to achieve the following Mapping of a function over multiple lists. ...
2
votes
1answer
394 views

Rank functions of n by their order of growth

I'd like to rank some functions according to their order of growth (e.g. n^2 < n^3). I'm not sure how to do order of growth in mathematica, so I was trying to ...
3
votes
2answers
331 views

Replacing values above a threshold with 1 [duplicate]

I have a list with some values and I want to replace a value which is greater than 1 with 1 otherwise keep the value. In this case 10562: ...
1
vote
2answers
87 views

Unknown limit of an array of area integrals

Could someone explain why Mathematica can't finish computing this limit (this is a limit of an array, when n -> Infinity (n ...
7
votes
5answers
327 views

LengthWhile until first duplication

I have the need to trim each of a large number of potentially very long lists (10^6+ elements) to the length where the last occurrence of any distinct element happens, or said another way, where the ...
1
vote
1answer
73 views

How can we tell Series to treat the expansion parameter as an integer?

It is simple for Mathematica to find an asymptotic expansion for $\frac{1}{-1+p}$ as $p \rightarrow \infty$. However, if we want to restrict $p$ to be an integer and also include some terms that ...
2
votes
2answers
234 views

ContourPlot - plot only one connected component

How do I plot only one component in ContourPlot when specifying a height. For example, ...
3
votes
1answer
509 views

Parallel evaluation and memory use

I have never used Mathematica's parallel evaluation before and have some trouble getting it to work properly. For the record, I am running Mathematica 9 on Linux with an Intel Core i7 processor (4 ...
9
votes
2answers
406 views

Why do I get a different value when I change the order of integration?

I think the following two-dimensional integrals should be equal, since they both integrate the function over the half plane defined by $t>\tau$. $$\int_{-\infty}^\infty \mathrm{d}t ...
0
votes
1answer
59 views

Function output of two lists are only diagonal elements

I'm having a little crysis over here. What I basically want to do is some sort of 3D-Plot, but I'm only interested in the resulting values. I have two vectors x and p: ...
7
votes
1answer
257 views

Better way to get Fisher Exact?

I want to perform a Pearson's $\chi^2$ test to analyse contingency tables; but because I have small numbers, it is recommended to perform instead what is called a Fisher's Exact Test. This requires ...
1
vote
1answer
98 views

Experiment with TagSetDelayed involving Part

Reading Associating Definitions With Different Symbols, I was intrigued by this: You can think of upvalues as a way to implement certain aspects of object-oriented programming. A symbol like ...
1
vote
1answer
120 views

Improper mutiple integral

I would like to solve the following integral: ...
5
votes
2answers
168 views

FactorInteger over UFDs

How can I factor 'integers' over other quadratic number fields (not just gaussian integers). For instance, how could I factor $7 = (3 + ω)(2 − ω)$ over Eisenstein integers ($ω = \frac{-1+ I ...
3
votes
2answers
800 views

Add Point to Plot3D

I'd like to simply add a nice thick point in $(0,0,0)$ to Plot3D[(y^2/x), {x, -3, 3}, {y, -3, 3}]. The solutions I came across to add anything to ...
1
vote
1answer
400 views

How to manipulate some list-plot in Mathematica

I have two separated matrices in the form X[[i*dx,j*dt]] and V[[i*dx,j*dt]] where i & j are integers from (1 to N) & (1 to M). V & X are velocity ...
1
vote
1answer
132 views

OpenSQLConnection error

I used to be able to connect to a SQL Server database. I haven't run this program for a few months. I tried it today and it failed, so I went back to try OpenSQLConnection[] and got the following ...
0
votes
1answer
94 views

Constraining some rows from LeastSquares to lines

For two matrices, A and B, with dimensions {n,p} and ...
0
votes
1answer
279 views

Using an image as a moving object in an animation

I have following animation: ...
0
votes
2answers
170 views

Define a function on a parameter argument set to zero

Say I have an expression (matrix) that depends on several variables. f= {{a, b+c},{2a-b^2,c^5+a b}} I want to define new matrices with the single parameter ...
0
votes
1answer
69 views

How to ignore terms containing in the summation of multiplications

n=4;L=3; p0[n_Integer]:= Product[ Sum[Subscript[r, k][l, l], {l, L - 1}], {k, n}] // Expand; How to ignore terms containing three or more multiplications of [2, ...
3
votes
1answer
78 views

Table doesn't replace inside conditionals (If, Which) [duplicate]

This: Table[If[cond, y], {y, 1, 3}] outputs this: {If[cond, y], If[cond, y], If[cond, y]} The ...
1
vote
0answers
34 views

custom precedence for custom infix operator with InfixNotation [duplicate]

I am trying to define several custom operators with custom precedence to implement geometric algebra. Loading the notation package << Notation` I can ...
1
vote
3answers
144 views

More elegant/efficient solution to browse through an array

I have an array of lists and want to correlate every list with each other like this: ...
1
vote
0answers
112 views

Load a Mathematica Notebook using .Net code

I have gotten a tremendous amount of information from the question posted at (Load a Mathematica Package via .Net code), which my application is very similar to. Specifically in that thread, the ...
0
votes
0answers
68 views

DSolve cannot solve for certain branches of the solution help pls

I get an error message while trying to compute this code.. help pls ...

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