All Questions

19
votes
2answers
747 views

Efficient Generation of Random Variates from a Copula Distribution

I have a 7-asset portfolio for which I want to simulate daily log-deltas using a Student T copula. The marginal distributions are all either Stable or TsallisQGaussian. Using NMaximize, I have ...
0
votes
0answers
48 views

how to interactively select points inside certain region in a plot [duplicate]

Very often I encounter a situation that I want to select some points inside certain areas of a plot. For example, ...
1
vote
2answers
117 views

How to use SaveDefinitions when using Rasterized Frames for a ListAnimate?

In another post (Is it possible to prerender animation in Wolfram Mathematica?) I got a good way to prerender frames in order to get a smooth animation using ListAnimate. I need to save the Animation ...
1
vote
0answers
32 views

Define a second name for a function [duplicate]

I'm working with an own package of functions. During development I noticed, that my naming scheme is not that clever; for example some of my functions are starting with capital letters. But I have ...
2
votes
1answer
203 views

Print out all functions in Mathematica

Sometimes I only remember parts of a function name and I want find that function name quickly, and if I search in the document center, it will give too much informations related to that and difficult ...
22
votes
7answers
880 views

How do I get my equation to have the form $(x-a)^2 + (y-b)^2 + (z-c)^2-d = 0$?

I want Mathematica to express the equation $$-11 - 2 x + x^2 - 4 y + y^2 - 6 z + z^2=0$$ in the form $$(x - 1)^2 + (y - 2)^2 + (z - 3)^2 - 25=0$$ How do I tell Mathematica to do that?
1
vote
1answer
960 views

How do I make function A create and return function B?

My basic need is I have to take lots of data and other information and assemble it into a function (static parameters). I then need to call the function many times for numerical results for many ...
3
votes
5answers
425 views

How to combine some elements of a list?

In order to simplify my expression, I face a list manipulation problem. For example, given the input list ...
2
votes
1answer
198 views

My Data has negative and positive numbers, can I still use it to get the PDF?

I have data that reflects the arrival time of a flight. {3, -2, 16, 13, -6, 5, 4, -7, 7, 0……..n} this is for 8:45am and has 150 elements "arrivals" The positive values represent the time in minutes ...
5
votes
1answer
226 views

Is there a way to track the Simplify process?

Is there any way to track how Mathematica actually performs Simplify, so that we can see what those "Automatic" transformation functions it applies are and how it ...
8
votes
1answer
151 views

Retrieving the text of a message

Is there a simple, built-in way to retrieve the text of a message, given it's identifier (such as Power::infy)? The documentation describes how ...
1
vote
1answer
228 views
2
votes
2answers
4k views

Plot 4D data with color as 4th dimension

I have a list of 4D data (x position, y position, amplitude, wavelength). I want to plot x, y, and amplitude on a 3D plot and have the color of the points correspond to the wavelength. I have seen ...
6
votes
1answer
145 views

How to calculate only four elements per column in a block matrix?

I have a matrix generated like this : Table[Sequence @@ {f[t[[i]], j, x], g[t[[i]], j, x]}, {i, 16}, {j, 3}] where $f$ and $g$ are two different functions, $t$ ...
8
votes
1answer
270 views

Optimizing the performance of an algorithm

First - a bit of an introduction. If you're only interested in the code, you can skip this section. The following question is drawn from Dennis E. Shasha's Puzzling Adventures, and is listed under ...
2
votes
1answer
422 views

Intermediate variables in NDSolve

I'm interested in using NDSolve as an integrator for a system of differential equations that looks like the following: ...
7
votes
4answers
2k views

How to add a common color legend to a grid of density plots?

I have a grid of density plots, say something like: GraphicsGrid[Partition[Table[ DensityPlot[Sin[i x] Sin[y/i], {x, -4, 4}, {y, -3, 3}], {i, 1, 4}], 2]] I ...
2
votes
1answer
918 views

Polar Plot of a two variable function

I am trying to make a polar plot of a two variable function, which has a radial and an angular part. For instance Y[r,φ]=r^2 Cos[φ]. I can make this plot using ...
0
votes
1answer
162 views

Choosing a solution to plot

I'm solving a system of equations that gives me three solutions and then plot a series of solutions depending on a parameter. The problem is that I have to choose different solutions depending on ...
5
votes
5answers
647 views

Subdividing a polygon , equivalent fractions

I see that I was a real "doofus" here and my original question was flawed. You can't divide a polygon like you can a circle or a rectangle, except in special cases... I should have seen that right ...
21
votes
0answers
2k views

Simplify matrix algebra

I'm trying to simplify some matrix linear algebra, for example, simplify $$\big(a1\times(A1\cdot A2)\big)\cdot\Big(a2\times A3\cdot A4+(a3\times A5)\cdot(a4\times A6)\Big)^{T}$$ where lower case ...
2
votes
3answers
467 views

Selecting subsets of a list containing a specific element

I'm trying to generate all the subsets of a set containing a specific element. For example, for the set {1, 2, 3, 4}, with the specific element I want inside each subset being 4, the required answer ...
4
votes
2answers
428 views

Finding all/most roots of a discontinuous function more consistently?

I have the equation: f[x_]:=α Tan[α*a] - Sqrt[c - α^2] and ideally I want to find all of its positive zeros, given a and c, with variable alpha. The problem is ...
3
votes
1answer
323 views

System Dialog Input with Button

I am trying to create a button that uses SystemDialogInput["FileOpen"] to browse for a file and assigns the file name to a variable. For example: ...
0
votes
1answer
83 views

How do I get output size to stick? [duplicate]

I have increased size of text to something I can read comfortable. When I delete output and evaluate notebook again with any changes made, the output text size returns to eyestrain inducing size.
1
vote
1answer
110 views

LogLinearPlot, extact data to a file, part 2

My question is based on the discussion that I started: Plot, extract data to a file The method proposed works well for the Plot command, but what about ...
5
votes
1answer
170 views

How to stop Manipulate changing view point

When using the following manipulate I can rotate the plot and manipulate the value without my view point changing; ...
4
votes
5answers
139 views

Convert a list with three arguments {x0,x1, step} into an equidistant table?

How can I convert a list such as: a = {1, 2, 0.1} into sequence so that I can pass them into a function, e.g. I want to be able to do something like this ...
9
votes
0answers
1k views

Download Mathematica 8 Trial

My school uses mathematica 8 on several of their computers. I would like to download a trail version for my home computer. I would like the same version. Is there a place I can download mathematica ...
-1
votes
1answer
208 views

Improving ContourPlot and Table output

I am trying to examine the results of and NDSolve solution for a BVP, and the output is not at all "pretty". Here's the code: ...
8
votes
3answers
416 views

Multiply a list of matrices by a list of vectors

How does one multiply a list of matrices by a list of vectors, elementwise? For example, multiplying ...
15
votes
2answers
1k views

Angular Range in Polar Plot

I am trying to make a polar plot using the following code ...
9
votes
2answers
208 views

Can one affect the appearance of components of a control?

I'd like to control the appearance of the components of a TabView[] control. Such a control appears constructed of Buttons, ...
2
votes
2answers
153 views

Using DeleteCases and Map together

Given: list1 = {{"a",1},{"b",2},{"c",3}} I would like to delete any pair in list1 that does not have a first element that belongs to list2. Example 1: If ...
2
votes
3answers
1k views

How to calculate partial derivative of an unknown function

How can I force Mathematica to calculate symbolically the partial derivative of a function u[x,y] with respect to a variable ...
8
votes
2answers
470 views

Problem with ContourPlot3D

The following line works fine: ...
3
votes
2answers
162 views

Sequence and boolean And

I'm trying to figure out if a calculation result it's a valid result. As it return a matrix, I need to test that every element it's a number, so I thought this could work... ...
0
votes
1answer
314 views

How Simplify and Assume can be combined on matrix products?

What I am trying to do is to simplify some expressions involving matrices! The problem is that Simplify[] considers the simplifications based on alphabetical order and everything is Commutative. For ...
3
votes
1answer
148 views

How to get VertexDelete to work?

I'm using Mathematica 9 and want to delete a single vertex and all associated edges on a graph but can't seem to get the function VertexDelete function to work. My code is below. I declare a graph ...
7
votes
1answer
2k views

Tensor analysis

Has anybody used tensors in Mathematica? How to properly work with them? I find Mathematica not very friendly in this field, as I am defining my own functions for lowering & raising indices, ...
9
votes
1answer
213 views

Creating a number based on given conditions

In the grade 7 math curriculum here in Alberta we teach divisibility. I'm trying to write a program to create questions based on the idea of a student being given say, 4 digits, and then choosing ...
6
votes
2answers
230 views

ListPolarPlot Labelling Points on the Plot

I have created a ListPolarPlot using the code below. I need to label the lines that extend from the centre to the outer ring. I do not want to label them with the values that these lines represent but ...
7
votes
6answers
625 views

Manipulate and Turning Expressions into Functions

I've been trying to use Manipulate to do interactive plotting, but I've been running into a few problems with saved expressions. I have an expression saved as "func" and I want to work with it and ...
0
votes
1answer
805 views

Nested Nintegrate - two variable limits of integral

This is, so to say, the next part of the question: Nested NIntegrate - NIntegrate::inum: - error Now I define three functions: ...
5
votes
2answers
540 views

ListContourPlot interpolation screws up on concave set of data

I want to create ListContourPlots for sets of Data (from a physics simulation) given as Triplets {x, y, f(x, y)}. Certain parameter regions in the x-y-plane are ...
7
votes
4answers
471 views

Find list position and mapping list

Sorry, my English is not very good. I have two lists: ...
8
votes
3answers
376 views

How can I prevent kets to from growing too large?

In TraditionalForm, Mathematica formats kets incorrectly in certain expressions. For example, if used in a summation with indices indicated, a ket becomes too ...
18
votes
1answer
325 views

Copying one symbol into another

I would like to know how can I completely copy one Symbol to another. When I say copy, a refer to UpValues, DownValues, ...
3
votes
0answers
134 views

Beginner: Saving & Reloading but Preserving Input/Output [duplicate]

This is my first post on this StackExchange. I made a Mathematica Notebook with a simulated data set the other day, just to learn the basics of making different graphs and creating a linear ...

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