1
vote
1answer
194 views

How can we ensure the result of Mathematica is exactly correct?

This is an example, I plot a function and find it has a defect when x approximates 400. Plot[Cos[.3 x] Exp[-0.01 x], {x, 0, 1000}, PlotRange -> All] Another ...
3
votes
1answer
226 views

Improving ListContourPlot mesh triangulation

I have a irregularly placed measurement data. I bring here a small example. I am sorry for that. mdata = {{20., 1.6, 0.218084}, {4.02807, 1.71068, 0.227565}, {19., 1.6, 0.240074}, {18.8333, ...
1
vote
1answer
195 views

Assign values to variable names in lists

I hope somebody can help me in this (I guess) simple question: I have a list of variable names ls={w0,w1,w2} and another list of values ...
0
votes
2answers
98 views

How do I sum up p items in a sequence?

I have the following sequence list = {p1, p2, p3, p4 ....} I am summing up the p items as follows: p1 + p2 + 2*sqrt (p21*p2) = p12 p12 + p3 + 2*sqrt (p12*p3) = p123 p123 + p4 + 2*sqrt (p123*p4) = ...
1
vote
2answers
342 views

Loop until convergence of two variables

I have the following program which i need to repeat steps until until two variables converge and I want this to be printed with the number of iterations: What I have : Input variables: ...
25
votes
1answer
569 views

Is it safe to launch/close kernels in the middle of a parallel calculation?

It appears that it is possible to launch additional kernels (or close existing ones) during a parallel calculation. The newly launched kernels will be utilized for the rest of the calculation. ...
3
votes
1answer
749 views

Export high resolution figure causes missing ticks

I understand that Mathematica has a bug when exporting images. The ticks are scaled not correctly when exporting at high resolution. For example: when you do: ...
6
votes
2answers
285 views

How can I create a class of matrices programmatically?

I am trying to figure out how to create a function that can create the matrix pattern below, where: f[1] returns {{1}} ...
17
votes
3answers
2k views

How to calculate volume of convex hull and volume of a 3D object

I have a set of random 3D data points. How can I calculate the volume of the convex hull?
5
votes
2answers
488 views

How to use a ConvexHull as RegionFunction?

I have a set of data supported over a region in 2D. I want to use RegionPlot and ContourPlot on interpolations of my data, but want to restrict the Plots to the region over which my data is supported. ...
45
votes
1answer
2k views

How can I manipulate TemporalData?

Version 9 introduced TemporalData but, truth be told, the documentation doesn't suggest that one can do much with it. Many of us have probably assumed we'd be ...
2
votes
2answers
384 views

Convert DelaunayTriangulation-> Graph->AdjacencyMatrix

Is there a way to convert a Delaunay Triangulation into a Graph structure so that one can generate an AdjacenyMatrix of the Delaunay?
5
votes
2answers
154 views

Generating EventHandler using Table

I would like to change the edge color of a graph when double clicking on it, the following code works: ...
6
votes
2answers
372 views

Does Eigenvalues evaluate in a parallelized way?

I use mathematica on a computer with linux operating system. The computer has 2 cpus and each cpu has 4 cores, so there are totally 8 cores available. Now I got confused with whether the evaluation ...
2
votes
2answers
183 views

Choosing a branch of the square root when performing a series expansion

I have the following problem. Consider expression f=Sqrt[(x-2y)^2] There is an obvious ambiguity in the definition of f ...
3
votes
2answers
723 views

In a ListPlot of LinearModelFit, plot error band

This is similar to this question. The fitted line can be plotted alongside with the data with this code: Show[ListPlot[data], Plot[lm[x], {x, 0, 5}]] I would ...
7
votes
3answers
439 views

Nested list to graph

The following nested list can be regarded as a representation of a (tree) graph: ...
2
votes
1answer
187 views

Using FortranForm

I need to use in Fortran, matrices that I create in Mathematica, therefore, I need to format them, so that Fortan can understand them. I focus on the simplest example: Let's say I have tha matrix A ...
1
vote
0answers
98 views

Historical Prices via FinancialData

I downloaded the historical stock prices for some stocks in the period 1990-2013 via FinancialData some months ago and computed the financial returns. Now I downloaded the data again for the same ...
4
votes
3answers
143 views

Creating nested matrix using random integers

How do i create 15x2 matrix with 2x2 random integer elements? My code only returned identical 2x2 elements:
1
vote
1answer
415 views

Plot has red 'film', no error message

I am encountering really strange behavior: I wrote a function that plots values some data. After executing the code the resulting plot has the red 'error' colour, but only momentarily (maybe 0.1 sec). ...
0
votes
1answer
177 views

How to include constraints in `NMaximize`

I am trying to find maximum likelihood estimates of parameters for a fairly complicated multivariate distribution. The support of the distribution depends on its parameters so I need to include some ...
1
vote
0answers
78 views

Calculating the recursion at the Fourier domain

I would like to calculate the following recursion with mathematica $$f_n(x)=\int_{B}^{A}f_{n-1}(x-\omega)f(\omega)\mbox{d}\omega\quad\quad f_1(w):=f(w)$$ This is simply the convolution of $f$ with ...
17
votes
3answers
3k views

Making Axes logarithmic in 3d plots

I've been trying to get loglog plots in 3D, but to no avail. My initial approach was to take the logarithm inside the plot i.e ...
2
votes
2answers
393 views

Making a flag with six vertical stripes

A flag is to be made with six vertical stripes by using colours yellow, blue, green and red in such a way that no two adjacent stripes should have the same colour. In how many ways is this possible? ...
2
votes
2answers
123 views

Multi-legend issue in ChartLegends?

Been fiddling around with the legends and trying to place one in each corner and I bumped into an issue: ...
2
votes
1answer
139 views

how to find iso-cost contours on a 2d plot efficiently

Consider a 2D plot in which dimension 1 and 2 represent quantity 1 and 2 respectively ranging over 0 to 100. Each point in the space corresponding to (x,y) represent cost of choosing quantity 1 as x ...
4
votes
1answer
131 views

The algorithm of ListGraphs[n,m]

I'm not sure if this is a Mathematica problem, math problem or a CS problem, so if this is off-topic please transfer it. In the package Combinatorica there is a ...
6
votes
5answers
803 views

Write any positive integer as a sum of squares

With n = 17 I would like to get {4, 1} and with n = 999 {31, 6, 1, 1} so that, for example, ...
1
vote
1answer
116 views

Integrating a function forcing parameters to be real and positive

I'd like to integrate the function $f(x)=x^{a-1}e^{-b x}$ over the interval $[0,\infty)$. f[x_] := x^(a - 1)*Exp[-b*x] Then: ...
0
votes
1answer
84 views

Numerical integration with purely numerical integrand

I'm trying to perform a numerical integral with an integrand that should not be manipulated with any symbolic preprocessing whatsoever. Consider the following simple test : ...
5
votes
3answers
295 views

How to highlight the whole selected cell

Is there any way to highlight the whole selected cell? some times if I want to delete a certain cell and if the code is long and cells are without output, it is hard to know which cell that you are ...
1
vote
2answers
103 views

How to eliminate (hide) output numbers in a slide show

I am creating a slide show with several imbedded Manipulate objects. I can hide the Manipulate command by clicking on the ...
4
votes
2answers
165 views

Solve a system of M equations without specifying M

This post has been edited heavily in response to the comments: my initial question was very confusing. I am trying to write my game-theoretic model in Wolfram Language. There is only one remaining ...
1
vote
2answers
78 views

Compiling function with predefined expression

I'm using the Compile function in Mathematica to compute say the following : f=Compile[{x,_Real},Cos[x]] Then I can compute f[x] for x taking any real value. Ok, ...
3
votes
2answers
144 views

Vertex Names of Subgraph in Order of Connectivity

I extract path subgraphs $P_4$ of an undirected graph $G$. And want to list the VertexNames of the subgraphs in the same order as they are connected. Here is an example: ...
2
votes
1answer
76 views

Defining a function (but not explicitly)

I have a question that must have a simple answer, but googling and searching this website did not produce an answer, so I'm asking it here. I'm working with three variables $x, y, \theta$, and I want ...
1
vote
3answers
697 views

How can i get the solution of complicated equation?

This is the equation about zeta. NSolve[eq] could not solve this equation. (I think it is too complex to solve by NSolve.) I ...
0
votes
0answers
108 views

Change Default Font Color of Commands [duplicate]

I encountered to two problems with Mathematica: one: How can I change the default font color of commands and functions in Mathematica (which is black) to another color, so that whenever I wanted to ...
0
votes
2answers
327 views

Absolute value and argument of a complex expression

I would like to find the absolute value and the argument of the expression: $ x + \sqrt { x^2 + y^2 } $ under the assumption that the absolute values of $ x $ and $ y $ are equal. I have written: ...
1
vote
2answers
112 views

What is the 'Mathematica-way' to test a variable transform?

Hello Mathematica experts. I would like to play around with a simple variable transformation, to test some claims about it. I wonder if there is a Mathematica-like way to do this. The specific case ...
0
votes
1answer
189 views

How can I obtain the complex root of an equation with FindRoot

I want to obtain the complex roots of some equations that are similar,but each of them has a different condition. this difference is the value of α in these ...
1
vote
0answers
1k views

NIntegrate: integrand has evaluated to non numerical values

I have pasted a code that has been giving me some trouble and errors when I try to compute. ERROR: "The integrand 1435.1232 E^(-6.4703566*10^6 s^2) deEntrance[s,phi]^2 has evaluated to ...
2
votes
3answers
588 views

Tracking iterations of a function

I'm learning MMA with Wagner's book. On page 41, he uses this to display the iterative steps of a FindRoot. However, I can't seem to replicate this (code at end), perhaps due to the difference in MMA ...
3
votes
2answers
292 views

Integration and Fourier transform

I would like to calculate the distribution function from the characteristic function. There is a formula given as $$F_X(x)=\frac{1}{2}+\frac{1}{2\pi}\int_{0}^\infty \frac{e^{i w x}\phi(-w)-e^{-i w ...
26
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 ...
0
votes
1answer
156 views

Inverse of a restriction of a non-invertible matrix

Let $A∈R^{4×4}$ be a non-invertible matrix, with $2$-dimensional kernel. How can I compute the inverse of the restriction of $A$ on a subspace where it is invertible: $A^{-1}v \,\,\,\,$ where ...
1
vote
0answers
275 views

NIntegrate (multi-dimensional integral)

I am interested in the numerical evaluation of the following integral: $\int \prod_{i=1}^n dx_i \delta(\sum_{i=1}^n x_i) \prod_{i=1}^n f_i(x_i)$ where $f(x)$ is a complicated function. Unfortunately ...
0
votes
1answer
137 views

Two questions on strategies for quantifier elimination

With the help of people here I was able to solve several cases similar to IC3 but this case - unlike the other cases - does not return an answer. I will try to run it for a day with 8 processors but ...
5
votes
2answers
1k views

Calculating the area under a curve, but above a certain threshold value

so here I am with a time series of data (hours (t) and corresponding measurements (a)). ...

15 30 50 per page