2
votes
2answers
409 views

How can I build a GraphicsGrid of arbitrary size?

This is actually a very simple scenario, in order to make simpler this question Part I. Consider the following piece of Mathematica code ...
2
votes
1answer
324 views

Mesh inside Plot legend

I have a plot for which I would like to create an legend that is black and white printer friendly. I have seen Jen's legendmaker but I don't know how to adapt it. I need help in making the legend for ...
2
votes
2answers
673 views

Dynamically choosing which Manipulate controls to use

I have some stuff I would like to manipulate, using two different kinds of control, one at a time, using another variable as a switch. These controls are similar in principle to ...
2
votes
2answers
887 views

Manipulate a Differential Equation result

I want to Manipulate the result of Differential Equation like : ...
2
votes
1answer
186 views

How to set PageWidth when using PutAppend to append expressions to a file?

Do[ PutAppend[Table[i, {RandomInteger[100]}], "./file.m"], {i, 100} ] I'd like each inner list to always appear on the same line, but not automatically ...
1
vote
1answer
185 views

Locating Periodic Orbits

Here is the code for the numerical integration of an orbit. First the module for the definition of the equations of motion. ...
1
vote
6answers
230 views

How to build a game board [duplicate]

I have - rather lazily - constructed a chessboard like this: ...
1
vote
2answers
332 views

3D Contour Plot parts of sphere with gradient less than 0, equal to 0 and more than 0

I want to plot only parts of the sphere of radius 1 where the gradient $\frac{\partial z}{\partial x}$ is < 0, = 0 and > 0. The full sphere is given by: ...
1
vote
1answer
249 views

Performance of compiled functions (Project Euler No14)

I was playing around with the project euler problem 14. The solution I came up with is listed below as cf1. The solution works fine but I get the compiler warning: ...
1
vote
2answers
70 views

Unintentional function memoisation via Dynamic

I needed to display edge labels of a graph in a way that allows the edge labels to be moved. ...
1
vote
2answers
502 views

Research positions of lists of varying size

I'm new to the site and I am French, so I ask your indulgence for my future mistakes in English. I would like to optimise the following code : ...
1
vote
2answers
208 views

MathLink Graphical Output (Plots) to File

In a custom Mathematica frontend based on MathLink I try to make use of plots produced in Notebooks. The idea is to write them to files whenever they get produced. According to C-code snippets I ...
1
vote
2answers
404 views

Collatz Tool Box — any speed ups possible?

I have created a tool box for experimenting with the Collatz conjecture. Info here: Wolfram MathWorld and here: Wikipedia The patterns I have found allow us to make the conjecture jump through some ...
1
vote
3answers
334 views

Fitting data without an equation

Let's say I have some data generated by anything. For practical sake, let's say I was able to generate a sequence of numbers through a recursion and I listed them out through a table of numbers. ...
1
vote
2answers
1k views

Can I improve the importing speed of Excel data?

I have data in an Excel spreadsheet that has 4 rows and 1,000 columns. I am using Import as follows: ...
1
vote
1answer
171 views

How can I create some shorthand notation for a custom control?

Per this question, I have created a custom graphical control object which evaluates to a list of values. I would like to be able to create such an object quickly, rather than typing some command, ...
1
vote
4answers
2k views

How do I plot x[t] vs. x'[t] (where x[t] and x'[t] are solutions to NDSolve)?

I have a differential equation which I solved using NDSolve. I can easily plot x[t] vs. t, x'[t] vs. t, but.... how do I plot x[t] vs. x'[t]? I tried using the Evaluate function to simplify things, ...
1
vote
2answers
421 views

Making a plotted curve interactive

Is it possible to make a plotted curve interactive in the sense that when hovering over it a line is drawn from the "hovered" point to one (or both) of the axes. I did do my homework, I just can't ...
1
vote
4answers
5k views

Creating a data1 versus data2 plot?

I have a table of data with multiple rows and columns, and I have to make a versus data table using two of these columns. Essentially, I have to set one column of data (column 3) as the y-axis and ...
0
votes
1answer
59 views

How to summarize the coefficient in Notation?

With the help from Stephen Luttrell in stackexchange, I can give an intuitive expression of quantum walk, as shown in the Mathematica codes below. ...
0
votes
2answers
164 views

Least Square Fitting

stuck on a mathematica assignment and could really use some help. A) Fit a function with the shape log(Y) = a0 + a1log(U) to the datapoints (log(Ui), log(Yi) with an least square fitting. Show this ...
0
votes
1answer
264 views

How can I build a GraphicsGrid of fixed size that rearranges the empty plots?

OK, let's make one final attempt; they say the third time is the lucky one! Following @rm-rf 's suggestions, I will try to be as clear as I can. My Mathematica code reads and plots simultaneously ...
0
votes
0answers
281 views

Is it possible to create an event handler for changes in values of variables?

I am creating a networking application in Mathematica that runs a non-stop simulation, and periodically receives new information from the remote server that affects the simulation. Whenever values ...
0
votes
1answer
796 views

Adding precision for the calculation of a function

I have some function $f(x)$ I wish to evaluate, which is yielding divide-by-zero errors for sufficiently large inputs. How do I increase the precision with which this function is evaluated in order ...
0
votes
1answer
267 views

How do I numerically solve a custom function?

Whenever I use functions like FindRoot or NDSolve, it sends x through the function and deals ...
24
votes
2answers
312 views

Bug in ArcLength?

fixed in 10.1 (windows) With Mathematica 10.0.2: ArcLength[Line[{{0, 0}, {1, 0}, {2, 0}}]] ArcLength[Line[{{0}, {1}, {2}}]] (* 2 *) (* 2 *) However, ...
18
votes
9answers
1k views

How to replace an element in a list based on the value of the next element?

I use Mathematica a little bit. I try to understand it, but it is hard I have a list of 5 numbers selected randomly from 0 and -1. I have to replace a 0 with a 1 when the 0 is followed by -1. My ...
18
votes
1answer
541 views

When exporting an (animated) GIF, is it possible to specify the size of the color palette?

I've exported an animation to animated GIF, which generated a 15mb file. I've been asked if I could regenerate the file, limiting it to only 16 colors, but I can't find any documentation on how I ...
17
votes
4answers
571 views

How do I introduce a new variable in a trigonometric equation?

I have the trigonometric equation \begin{equation*} \sin^8 x + 2\cos^8 x -\dfrac{1}{2}\cos^2 2x + 4\sin^2 x= 0. \end{equation*} By putting $t = \cos 2x$, I have \begin{equation*} \dfrac{3}{16} t^4+ ...
16
votes
3answers
406 views

Dataset seems unable to handle ListDensityPlot and ListContourPlot

If I create a Dataset: ...
16
votes
3answers
399 views

How can I set Grid alignments using numbers?

There is an example in the Alignment documentation (it also appears in the Grid documentation): ...
15
votes
4answers
596 views

HoldForm doesn't hold form

Bug introduced in 10.0.0 and fixed in 10.0.1 In Mathematica version 10, HoldForm no longer produces the same results as in version 8 (edit: I only have versions ...
15
votes
0answers
161 views

Exp is slower for some number ranges

I get a hit on performance with the Exp function depending on the range of my inputs. for example, with: ...
15
votes
0answers
131 views

How to keep the ctrl+shift+k help menu remain in display while typing?

In Mathematica 9, one can type ctrl+shift+k to display menu which has all the possible signatures/definitions for the function or command in question. One can ...
15
votes
3answers
471 views

Grabbing a number of characters around a string pattern

If I have some string data: text = StringTake[ExampleData[{"Text", "DeclarationOfIndependence"}], 400] "When in the Course of human events, it becomes ...
15
votes
3answers
1k views

Effective matrix power like algorithm

First example Suppose you want to calculate the 6th power of some matrix $A$. The brute force attempt of doing this is considering $$(((AA)A)A)A)A$$ which requires a total of 5 matrix ...
14
votes
2answers
318 views

Messages leak out from Block

fixed in 10.1 When assigning message to a symbol localized by Block, I would expect that this message is not accessible outside of ...
14
votes
2answers
531 views

PlotLegends -> “Expressions” not working when Plot given one function

I don't get a legend when I use the option PlotLegends -> "Expressions" when the first argument to Plot is a single function. It works OK when I give ...
14
votes
3answers
251 views

What's wrong with this pattern of the form Except[Repeated[…]]?

I'm trying to build a head that recognizes molecules. Here's the code ...
14
votes
2answers
4k views

Plotting vectors originating from the origin in 3D

I have an array of data with 3D elements. Ex: x = {{1,2,3}, {3,4,5}, {5,6,7}}. I want to show this data in 3 dimensions, such that each point in the space is shown ...
14
votes
1answer
571 views

Incorrect results for elementary integrals when using Integrate

There is a rather simple integral ($K_0$ is the 0-th order MacDonald function) $$\int_0^\infty e^{-x \cosh\xi}\, d\xi = K_0(x)$$ which mathematica cannot solve. This even though the documentation ...
14
votes
1answer
884 views

Why does CUDAQ (from CUDALink) download data from Wolfram servers?

I understand why functions like ElementData or CountryData need to download up-to-date data when first launched. However, when ...
14
votes
1answer
326 views

Count number of sublists with a total not greater than a given max

Suppose I have a list of positive integers: data={1, 1, 2, 3, 3, 3, 5, 5, 5, 7, 7, 8, 8, 9, 10, 10, 12, 16, 23} I want to count the number of subsets up to ...
14
votes
1answer
2k views

Parallelizing Numerical Integration in Mathematica

I have an ugly, six dimensional function that I need to integrate numerically. It works, but it currently take twelve hours to complete the calculation. Is there any good way to parallelize the ...
13
votes
0answers
197 views

What is ColorEqualSigns and how does one use it?

I'm setting up the SyntaxInformation for a package I'm writing and I'm struggling to understand what the "ColorEqualSigns" ...
13
votes
2answers
362 views

Why do NumberForm and Round apparently use different tie-breaking methods?

When rounding numbers (for example, rounding a real number to the nearest integer), the "round to nearest" rule is usually used. For example, 1.4 is rounded down to 1 and 1.6 is rounded up to 2. ...
13
votes
4answers
960 views

Evaluation of a triple sum does not finish in reasonable time

I'm trying to compute the following triple sum, but no result is produced within a reasonable amount of time. What to do? ...
13
votes
1answer
411 views

Evaluation indicator for a notebook

I have a GUI with a number of TabView and other Manipulate controls. Sometimes clicking from one tab view to the other can take ...
13
votes
4answers
2k views

How can I extract the maximum value from a Histogram?

In Mathematica 8.04 I've created a histogram of returns on a stock using: ...
12
votes
4answers
446 views

Elegant high precision `log1p`?

Sometimes it is hard to understand how numerical expressions are evaluated. I remember reading claims by Wolfram on how smart the Kernel is to evaluate expressions trees numerically by recognizing ...

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