3
votes
1answer
134 views

How to remove recursion, and write it functional and efficient way?

I wish to implement the following recursion efficiently. ...
3
votes
2answers
198 views

Difference between double quotes

I have a notebook and I enter something like PlotLabel->"my label with dynamic number "<>ToString[strange] and I get errors like However, the double ...
3
votes
4answers
273 views
3
votes
1answer
71 views

Computing kernels of a matrix in distinct cases

I have the following matrix: ...
3
votes
2answers
137 views

Change font of formula number in DisplayFormulaNumbered

I am trying to change the font of the formula number in a cell which has style DisplayFormulaNumbered. I can easily change the font of the formula I enter by selecting it and using the format menu. ...
3
votes
0answers
141 views

Generating function for Newton series?

The function GeneratingFunction gives generating function for Taylor series. Is there a similar function for Newton's series? $$f(x) = \sum_{k=0}^\infty \binom{x}k \Delta^k [f]\left (0\right)$$
3
votes
2answers
146 views

Expectation of a composite Markov-Gamma distribution

In a model I have a discrete two-state first order Markov process, defined by a (2x2) transition matrix with two free parameters. If the first state occurs then the process outputs zero for that ...
3
votes
5answers
365 views

How to add periodicity to condition?

Is it possible to set the following function f[a], where a can be any real number? $$ f(\alpha) = \begin{cases} 1 ...
3
votes
3answers
95 views

Replacing a sum of expressions

I have an equation which Mathematica solves but gives a huge output. However I notice in this output that the same expression occurs many times. Namely: $E=864 a^6 - 432 a^4 b^2 + 54 a^2 b^4 - b^6 + ...
3
votes
1answer
192 views

How to smoothly change the radius of a circle by dragging its circumference?

I am attempting to set an EventHandler to change the radius of a circle by dragging on its circumference. But the response to the dragging is terribly slow. What is ...
3
votes
1answer
213 views

How does epilog position work in logplots?

I'm trying to use Epilog in my plots but the position of the Epilog isn't making much sense. As a minimal example consider, ...
3
votes
1answer
87 views

Registering/detecting an importer by file name extension

I've developed an importer and exporter for FreeSurfer's MGH/MGZ file format; the specific format isn't important, but I was ...
3
votes
1answer
436 views

Solution given by Wolfram Alpha but not _Mathematica_

Why will Mathematica not give a soluion to Solve[Log[x] == Log[j, Log[j, x]], j], but Wolfram Alpha will?
3
votes
1answer
848 views

Plot a function based on Derivative - Gradient field

I'm trying to plot the gradient field of a function in such a way that is possible to change it easily, only editing the function. Consider the code: ...
3
votes
1answer
143 views

Is it possible to get AltGr key to work in Math.exe?

For some reason when you run Math.exe form windows command line, Mathematica disables the AltGr key. This is a bit annoying since my keyboard locale has the keys [, ], {, }, @, $, \, | located under ...
3
votes
1answer
751 views

Select row from a table by column value [duplicate]

I have the following: animals = {{dog, black, 200}, {cat, white, 100}, {moose, brown, 500}, {zebra,black,100}} If this came from a SQL table called animals, ...
3
votes
2answers
866 views

Intersection of surface with parallel planes

Consider the code (adapted from here) ...
3
votes
4answers
561 views

More elegant way

I read ReplaceOrRemoveInvalidOrMissingData Mathematica documentation, and I tried to apply the same approach to my dataset. I've got two problems, but one is only a style problem! There is one more ...
3
votes
1answer
513 views

ReadList with header and foot lines

I want to do some large data analysis, and i want to be able to import files in a fast way. I tried Import, but it is quite slow; ReadList takes half the time. This is the code I was using: ...
3
votes
3answers
169 views

Performance on Multinomial Deviate is slow

Most of the time in my program is spent on this single line of code: out = RandomVariate[MultinomialDistribution[nt, tmp]]; ...
3
votes
1answer
213 views

Simplify equations with pattern assumptions

When simplifying an expression using Simplify[expr, assumptions], the assumptions has to be explicit. Is it possible to simplify an expression with pattern ...
3
votes
3answers
314 views

How to do Cases with multiple related patterns?

I would like to write a function similar to Cases, but can search for a group of related patterns together. For example, ...
3
votes
1answer
191 views

Prevent Mathematica from “romanizing” a string of letters?

When I'm authoring in text style (Alt-7), I'll often include inline math. Whenever I enter two or more consecutive letters (e.g., $ax^2$), Mathematica will automatically "romanize" (or "un-italicize") ...
3
votes
3answers
418 views

Animation is jerky, but slider is not

When I do the following simple animation (from the book Mathematica Navigator, p. 316) the slider control changes the image smoothly, but when I play the animation it is jerky. Is there anything that ...
3
votes
2answers
356 views

Assigning an analytical approximation to the error function erf(x)

Working with some iterative integral equations, I have Gaussian density functions involved therein. Integrating the Gaussian function I obtain the error function. When I take the second integration, ...
3
votes
7answers
379 views

Concise way to generate multiset lists

I wrote the following to generate a multiset with the same number of items over a fixed range: ConstantArray[#, 3]& /@ Range[9] // Flatten ...
3
votes
4answers
719 views

Recursive function for calculating the arithmetic mean of a vector

I want to write recursive function for calculating the arithmetic mean of a vector. For $X(n)=\{1,2,3,\ldots, n\}$, the formula is ${\rm Mean}(X(n))=((n-1)\, {\rm Mean}((X(n-1))+X_n)/n$. My ...
3
votes
2answers
151 views

Cannot change ImageResolution after applying ImagePad

I want to export high-resolution images of a plot I'm making. The trouble is, the plot has a lot of extra white space around it which I get rid of via ImagePad (I ...
3
votes
2answers
238 views

Exporting graphics without X server

I have a Mathematica installation on a Linux server that is intended to be used for batch processing. Some of the things that will be processed will include rendering of graphics. However, if I use ...
3
votes
2answers
133 views

Moving a locator based on the movement of another

My problem is: I want two Locators to simulate a vector in the following sense: The first Locator is the base and the second ...
3
votes
2answers
418 views

Color of a plane in Contourplot3D

I have the following code example: ...
3
votes
2answers
197 views

Interpolating a sparse list of two-dimensional coordinates

I've run into a problem where I have an ordered array of sets of coordinates, for example: ...
3
votes
1answer
668 views

A rotation-like transform on a matrix

Do not be confused with comments, those are for previous version of the question - Kuba Imagine I have a matrix of the form: ...
3
votes
2answers
993 views

Units, plotting and empty plots

maybe I'm completely newbie but I can't understand the behavior of units and the command plot. I'm doing some easy plotting of the state equation for gasses: ...
3
votes
1answer
155 views

Issue with scope of variables

For the definitions, t = 1; f[x_, y_] := t (x + y); v[3] := {1, 1}; g[u_] := f[v[u][[1]], v[u][[2]]]; the following two expressions yield different results, ...
3
votes
2answers
486 views

RecurrenceTable with a recurrence function of two variables

I have to calculate the cool down process of a regenerative heat exchanger. I solved the problem in Excel before, but now I want to do it with Mathematica. I want to create a table with the variables ...
3
votes
1answer
270 views

Equating two lists, element by element

Say you have two lists: listA = {a, b, c} listB = {d, e, f} How would you produce a listC that equates each of the two's ...
3
votes
1answer
314 views

How to configure two Mathematica in different places with different settings

For some reasons, I should use two language versions Mathematica. The most reason is I want to see the comparison of Help page(English version and Chinese version) to improve my English, both are ...
3
votes
3answers
190 views

Picking certain pairs according to a condition [duplicate]

I'm a Mathematica beginner and can't find out a solution to my problem. I have a list of pairs of numbers, for example something like this, but much longer: list={{2., 3.}, {3., 2.}, {5., 4.}, {4., ...
3
votes
2answers
797 views

How can I consistently get a good logistic regression fit?

I'm executing the command NonlinearModelFit[data, c/(1 + a Exp[-b x]), {a, b, c}, x] with the data being ...
3
votes
1answer
1k views

Plot FindRoot for non-trivial function

I would like to plot the results of FindRoot over certain range of inputs. I tried to do this with the code: ...
3
votes
2answers
343 views

How can you combine lines in $\LaTeX$ and lines in Mathematica?

Suppose that you want to make a report about the golden section algorithm, and you want to explain the process with text in $\LaTeX$, and in every iteration you want to show in that report the values ...
3
votes
1answer
1k views

Join a piecewise plot

I wrote some code to get a piecewise plot which is displayed correctly. Now I'd like to join the various parts of the plot, using some kind of interpolation, to get a continuous chart even though it's ...
3
votes
2answers
752 views

Save variables values and definition

I used to do a lot of programming in R and recently switched to Mathematica. One thing that bothers me is that I haven't found a way to save variables, their values and definition! Let's look at an ...
3
votes
1answer
823 views

How do I read a CSV file and remove comments from it

I have very recently started using Mathematica 9.0 Home Edition and am trying to understand it as best I can so please be tolerant ;). I have a file of data (sugar.csv) which contains blood sugar ...
3
votes
2answers
514 views

Combining and separating sums

How can I combine or separate sums in Mathematica in the way that Together or Expand work for rational expressions? For ...
3
votes
2answers
815 views

How can I control the number format of exported data?

I'm having issues while exporting a tables of numerical values to "*.dat" data files. Here's the thing, sometimes when I export a table, I get more decimals on some random values. The problem is that ...
3
votes
5answers
587 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 ...
3
votes
1answer
772 views

Trying to plot a velocity profile in x-y plane

I have a velocity profile for two liquids on top of each other in a pressure driven channel. The profile is supposed to be parabolic. I plotted them up, but I can't manage to plot them in the x-y ...
3
votes
2answers
506 views

Deleting Print results

While playing around with $Pre and $Post I created this very annoying piece of code: ...

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