1
vote
4answers
388 views

ListPointPlot3D seen from above

I have a couple of {x,y,z} points a = {{0, 1, 0.}, {50, 1, 0.018931}, {100, 1, 0.02}, {0, 2, 0.}, {50, 2, 0.131}, {100, 2, 0.2}}; and I'm visualizing them with ...
3
votes
1answer
154 views

Problem with | operator in pattern matching

My first question here as I only got into Mathematica programming recently. Basically I have a large symbolic algebraic expression where I know certain variables with head pε appear with degree 2 in ...
-5
votes
1answer
292 views

plotting an equation with double summations

Thank you so much for the helpful comments. Now able to manage to plot all the functions. ...
7
votes
1answer
573 views

Compiling 64bit MathLink code under cygwin on Windows 7

I am aware that building MathLink executables is not without its challenges. However, I am trying to compile the MathLink example 'addtwo' from a makefile within cygwin on a 64 bit Windows 7 machine. ...
5
votes
2answers
270 views

How to dynamically update Locator[] constraints?

I need to visualize Menelaus' theorem for a triangle with moving locators for each of six points. So the vertexes of the triangle can move in any possible way, and the three points on the sides of the ...
4
votes
0answers
81 views

Is there a way to check whether two notebooks share the same variables?

When I code in Mathematica, I often re-use code from old notebooks which fulfilled a specific purpose; for example, one testing for soft matches in strings, or one that identifies outliers on a graph ...
0
votes
1answer
897 views

DSolve fails to solve second order PDE

I have a very simple example of a second order PDE: eqn = D[u[x, y], x, y] + u[x, y] == 0; sol = DSolve[eqn, u, {x, y}] and Mathematica cannot solve it! What is ...
1
vote
3answers
118 views

Placeholders for map inside a map

I have a list structured like list1 = {{"header1","header2","header3"}, {0,1,2}}; and I'm using a custom function to find the number of the column with a ...
1
vote
0answers
47 views

How to insert expression matching the format?

I would like programmatically to insert/write an expression at the current insertion point, but matching the current format, such as font size and style, so that it looks like the user typed it. ...
1
vote
1answer
634 views

Extract attribute data from an XMLElement

I'm trying to come to grips with parsing an XML file but I'm having difficulty working out how to extract specific attribute data from an XMLElement. Sample XML file below: ...
0
votes
1answer
281 views

Automatically shrink stretched images back to their original dimensions

We all sometimes find images on the web that are carelessly stretched to larger dimensions than original, which results in nothing but a reduction of the detail / dimensions ratio. See Original vs ...
0
votes
1answer
205 views

Dynamic boundaries for FindRoot

As documented FindRoot[f[x], {x, xs, min, max}] searches for a solution, stopping the search if x ever gets outside the ...
4
votes
1answer
1k views

How can I draw the transition diagram of a Markov chain?

I apologize for my heaviness as I am a Mathematica novice. Is there a kind soul who can tell me how to draw diagrams like those shown on page 158, 160 and 161 of this document.Chaine de Markov I ...
5
votes
3answers
530 views

Parameters for the CIE XYZ Color Space in Mathematica

In Mathematica, producing a color based on its RGB parameters is easy; one can use (for example) ...
3
votes
2answers
545 views

Adding and subtracting from elements in a list

I'm trying to solve an aparently simple problem. Given a list of length n, {a1,b1,c1,d1...} I want to perform two simple ...
8
votes
2answers
1k views

How to approximate a given WAV file with trigonometric series?

I'd like (together with a few people) to prepare a presentation about Fourier series for middle/high school students. I thought it might be quite cool to play a violin sound from, say, a WAV file, ...
9
votes
1answer
484 views

Modular arithmetic - efficiently calculating the remainders of factorials

When working on this question regarding the divisibility of the sum of factorials, I decided to write some code to test "small values" of the problem using the following code. ...
3
votes
2answers
1k views

Define a color function using Piecewise

How can I define a ColorFunction for my ContourPlot using Piecewise? For example after ...
3
votes
1answer
445 views

Adjacency List representation of a graph

I am looking to draw a graph knowing a simple adjacency representation of the graph like: A = {{1, 3}, {2, 3}, {3, 4, 5}, {4, 5}, {5}} Where ...
15
votes
4answers
409 views

How to remove duplicates from set of machine precision 2D points?

I have a set of 2D points with machine precision coordinates. I need to remove all duplicates. Performance is important. This is the most obvious fast solution: ...
1
vote
1answer
205 views

What do these error messages mean when numerically solving differential equations?

I am using Mathematica to numercially solve the following equations: ...
-2
votes
1answer
177 views

Fortran kind of matrix creation [closed]

I want to create the matrix H of dimensions nxn and matrix elements H(i,j). Because of the physical problem I am dealing with, it is necessary to build it in the following not trivial way. I know how ...
7
votes
1answer
200 views

Why does simplification in Mathematica depend on variable names

Mathematica fails to put the following into an obvious simplest form: ...
3
votes
2answers
807 views

Empirical Cumulative Distribution Function

I have a data set of the form $d=\{(y_1,x_1),(y_2,x_2)...(y_n,x_n)\}$ for a large $n$. A non-parametric plot of this data (a scatter plot where all observations are sorted along $x$ and joined with a ...
3
votes
1answer
194 views

How to build and operate a master Notebook?

Suppose you have some notebooks, they work for a family of related tasks, each one doing a certain task. Lets say Notebook 1 gets two inputs from its variables in11 ...
3
votes
1answer
292 views

Sum and NSum gives different solutions

I'm working on a Mathematica lab for Calc. 2, and I ran into a problem last night. I was trying to calculate the midpoint approximation of the definite integral of ...
2
votes
1answer
171 views

Can we give Mathematica hints for symbolic sums and products?

I have this question at MO and I would like to know if we can give hints to get the symbolic sums and products to come out as $\frac{6}{\pi^{2}}\pm\epsilon$ instead of $0.60792710...$ accurate to ...
1
vote
1answer
125 views

How to apply multiple format to a list

I have a nested list like matrix = {{1.2345664, 2.38673956, 3.567846}, {0.00034554, 124.4554654, 6.34543}, {0.0000233, 244.34454, 2}} and I want to apply ...
1
vote
3answers
1k views

Write a table to a file

I want to compute a multidimensional table in Mathematica and write it to an external file. Here is a simple example. I have three lists x, ...
35
votes
9answers
7k views

Generating a Sierpinski carpet

I am trying to draw a Sierpinski_carpet. I have code that works, but I think there is a more elegant way to do than my way. Maybe I couls use Tuples or ...
1
vote
3answers
220 views

How to select interactively datasets to plot with Manipulate

I'm using Manipulate to visualize three datasets: Manipulate[ListPlot[WHAT -> what], {what, {dataset1, dataset2, dataset3}}] Now with this solution I can only ...
5
votes
1answer
446 views

NestList and Euler's method

I am new to mathematica and so just experimenting with various programming constructs. Recently have been looking at NestList and how I could use this to implement ...
4
votes
2answers
1k views

Gram Schmidt Process for Polynomials

I want to implement the Gram Schimdt procedure to the vector space of polynomials of degree up to 5, i.e. I want to find an orthogonal basis from the set of vectors $v=(1,x,x^2,x^3,x^4,x^5)$. The ...
0
votes
1answer
81 views

Given a sequence of expressions, how can I convert them all into functions?

I have a sequence of expressions 1, x, x^2, ..., x^5 I want to define a sequence of functions out of it, what should I do? Namely I want to define a vector of ...
2
votes
1answer
94 views

Is there a convenient way to localize all variables in a new notebook? [duplicate]

I often digress to test some others’ code when working on my own problems. Usually, I have to check if there are conflict variables. Of course, it is not a wise way. By contrast, all the variables in ...
3
votes
1answer
113 views

Find root approximants for low-precision numbers

I want to be able to find low-complexity algebraic approximants to decimal numbers. For example, 1.41 can be approximated as a solution to the polynomial x^2==2. ...
0
votes
1answer
166 views

Simplify expressions that contain full derivatives

The best way to show what I want is by giving an example: How to go from ...
8
votes
4answers
142 views

Mark selected sub-lists in the list they were selected from

I've got this simple problem with two lists. I select some items from a list, but I want to visualize the difference between the previous list and the list that I create with ...
2
votes
2answers
131 views

How to make Mathematica returns the exact expression I typed

I'm using Mathematica to compare some constants. Before playing around with those constants, I would like to check that I didn't make any mistake in typing them. So my question is the following: "What ...
1
vote
1answer
130 views

Evaluate code to some point

How can I evaluate my code, up to some point? I don't want to evaluate all of my code always. I have to use Shift - Enter for every line from the first cell up to the point I want to be, and it's not ...
2
votes
1answer
361 views

Changing default range for x- and y-axis in ListPlot3D

How do I change the default values for the x- and y- axis in this example without altering the z-axis values? For instance, I want the x-axis to follow a range based on "x= 0.01 i+3" (not just i) , ...
-1
votes
2answers
453 views

How to simplify expressions containing derivatives

Is there a way to reverse the application of derivative rules in order to simplify expressions including derivatives? e.g. in Mathematica code: Want to go from ...
5
votes
3answers
1k views

Travelling salesman with start and end points for 30 points

I am doing a route optimisation for delivery vehicles and failing dismally. Please see problem statement below. My current solution uses FindShortestTour, but this does not have defined start and end ...
10
votes
5answers
685 views

Building a continued fraction

I've completed a problem that involves approximating $e$ by a continued fraction: $$\frac{N_1}{D_1+\frac{N_2}{D_2+\frac{N_3}{\ddots+\frac{N_k}{D_k}}}}$$ with the $N_i$ being the list ...
14
votes
2answers
358 views

Equidistant points on a polyline

Set of 2D-points connected by a polyline B-spline function: ...
5
votes
1answer
124 views

Scaling an image with “Drawing Tools” primitives on it

Imagine I doodle with the "Drawing tools" pen, or place lines on an image after importing it. Now say I want to scale this image by some constant factor $C$ while maintaining the same aspect ratio. ...
10
votes
1answer
311 views

How do I seamlessly migrate from the older Units package to Mathematica 9's Quantity objects?

I have several notebooks that make use of the Units package and would like to be able to work simultaneously with the older units and ...
2
votes
2answers
261 views

Introduction of bias during brightness and contrast manipulation of an image

Quoting from Nature magazine's "Image integrity" guidelines: Processing (such as changing brightness and contrast) is appropriate only when it is applied equally across the entire image and is ...
2
votes
2answers
231 views

How do I determine the original aspect ratio of an imported image?

Say I import a TIFF, JPEG, or PDF image. How can I quickly determine the original aspect ratio of the image so that I can properly scale its size? I have thus far been unable to find an answer ...
2
votes
1answer
128 views

Snapping two “Drawing Tools” objects together while decorating an image

I'm using "Drawing Tools" to decorate an imported image (a TIFF file). I need to create a set of regularly spaced parallel lines, and my solution for doing this is to create a pair of parallel lines ...

15 30 50 per page