11
votes
1answer
284 views

Is it possible to use Compile on a function with optional arguments?

My Mathematica is a little rusty, so apologies in advance. I think my problem is quite simple, but I can't seem to find the answer on my own! Simple example : ...
8
votes
2answers
200 views

How do I write a function that can be used in a rule to modify both sides of an equation? [duplicate]

I sometimes need fine grain control over equations in Mathematica in order to help me understand how to solve a problem manually. A greatly simplified example of a session might be something like ...
8
votes
2answers
513 views

Distorted graphics when using custom ticks and AspectRatio -> Full

Bug introduced in 7.0.1 or earlier and partially persists through 10.0.1 or later I am having a problem using custom tick specifications along with ...
1
vote
3answers
1k views

Finding the square root of a random number with Newton's method, using While/Do/For loops?

I am trying to construct a program that will find the square root of a number, using Newton's method, which is $$x(n+1) = x_n- f(x) / f'(x_n)$$ The number, will be a random number, generated by: ...
2
votes
0answers
114 views

Strange double evaluation using MorphologicalGraph

(MMA 9.0.0 on Mac OS/X 10.8) Please consider the following snippet (this is as SMALL as I could make it -- my attempts at making a smaller repro-case eliminated the effect that I am investigating) ...
1
vote
1answer
168 views

Efficient way to give symbolic elements symmetry

I have a symbolic expression that represents a set of operators. These operators have quite a bit of symmetry to simplify expressions: ...
16
votes
1answer
278 views

Exclude Sections/Subsections/… from evaluation

I'm working on a large notebook and I want to exclude some sections and subsections from being evaluated when I evaluate the whole notebook. Is there a way to exclude specific sections or ...
0
votes
1answer
493 views

NIntegrate Error-Estimate Question

When I do some complicated 4-dimensional integral numerically, Mathematica tells me its estimate for the value of the integral, and its estimate for the value of the error in the calculation. The ...
2
votes
2answers
2k views

How to make plot with frame and two different scales on the x-axis (CMB power spectrum example)

Let us take CMB spectrum as an example. I get data of $C_l$ as a function of multipole moment $l$. Also, multipole moment is a function of angular scale. The question is: how to make a plot with a ...
2
votes
3answers
1k views

Why doesn't Mathematica make an obvious simplification?

I am doing some calculation with summation and the Kronecker symbol. Here are my steps : ...
2
votes
2answers
2k views

Product of Fibonacci numbers using For/Do/While loops

I want to find the product of the first 20 Fibonacci numbers (the fibonorial). I want implementations using While, Do, and ...
7
votes
3answers
432 views

Piping and Replacement

I haven't been able to figure out how to use piping with certain functions. Specifically, I would like to apply a replacement at the end of a pipe, like the following: ...
2
votes
2answers
2k views

Faster way to convert real strings into numbers [duplicate]

Working with big files, I have to convert some numbers that are in string format into real MMA numbers. I know that I can use ToExpression but it's slow when ...
2
votes
1answer
251 views

Grid generation around airfoil from data

Here is the data http://wikisend.com/download/405620/datapoints.dat I have (x,y) data for a grid around an airfoil and I am trying to figure out how I can draw radial and polar lines for the grid to ...
4
votes
2answers
255 views

How can this DivisorSigma code be made fast?

Since Project Euler problems are now fair game for questions I have a question of my own. A certain problem* states: For a positive integer n, let σ2(n) be the sum of the squares of its ...
2
votes
1answer
578 views

Importing data sets from plain-text files and performing operations on them

I am working with a lot of daily weather files in the txt format. I need to calculate a daily quantity from each of them, e.g., daily light intensity, which ...
3
votes
3answers
664 views

Sum of Multinomial Coefficients

Basically, I want to write a function to compute the following sum $f(m,L):=\sum_{0\leq k_1,\cdots, k_n\leq m} \binom{m}{k_1,k_2,\cdots k_n}$ and $\mathrm{supp}(k)=L \subseteq \left \{ 1,...,n \right ...
7
votes
1answer
7k views

Quick Hessian matrix and gradient calculation?

I am absolutely new to Mathematica and I actually want to try implementing a little optimization method . Long story short assuming I have a predefined two-variable function f(x,y) I want to ...
6
votes
1answer
272 views

Obtaining standardised regression coeffiecients

Regression coefficients are the constant that indicate the rate of change in one variable as a function of change in another. Standardised regression coefficients are the same, but refer to a change ...
3
votes
2answers
142 views

Find condition under which variables fall away

I have a somewhat lengthy expression, looking like expr = 1 + x + b + Pi + 2*a Is there some way of generating a relationship between ...
0
votes
1answer
394 views

Where is KeyEventTranslations.tr in Mathematica 9?

I can't find the file in it's usual place /Library/Mathematica/FrontEnd/... was it removed?
1
vote
2answers
1k views

Parametric plot from two NDsolve solutions

I have two independent ODE systems. A = NDsolve[..., {x, y}, {t, 0, 10}]; B = NDsolve[..., {a, b}, {t, 0, 10}]; I can draw a ...
6
votes
0answers
339 views

Reproducing the Integral Definition of the Modified Bessel function

I need to simplify some integral expressions in terms of special functions, such as the modified Bessel function of the first kind. See for example Eq. (5) on this page. Notice that the real ...
6
votes
2answers
2k views

Is it possible to do vector calculus in Mathematica?

I am trying to rearrange and manipulate some vector differential equations in Mathematica. As far as I understand you have to tell Mathematica that a variable is a vector by specifying the components ...
1
vote
1answer
312 views

Summation of If statements

The following made me curious. Suppose you want to sum the if statement If[x[i] < 1., x[i]^2, 0.] over i=1,2, i.e. ...
2
votes
1answer
325 views

Directional derivative of SiegelTheta

I'm working on a problem where I have to integrate both the Mathematica function SiegelTheta and some of its second order directional derivatives. Using the function works well but something goes ...
11
votes
4answers
580 views

What is a good way to plot some difficult implicit equations?

Here are several equations, it seems that Mathematica couldn't plot them well, although I set PlotPoints>100 ...
5
votes
2answers
396 views

Improve performance and style of solution to Project Euler #32

Since I'm fairly new to Mathematica, I'm trying to learn better ways to improve my coding skills so I've turned to Project Euler and this site to speed up my learning pace. Anyways, I was trying to ...
0
votes
1answer
336 views

Create heat map from RMSD values

After looking through these forums for answers that could work for my problem, I could not find anything. I want to make a heat map comparing values that are in a nested list. That is, I have a ...
-1
votes
1answer
1k views

How can I make a plot of the Higgs potential?

I was wondering, how would could I make a drawing of the Higgs potential aka "mexican hat potential". I am quite new to Mathematica and don't know where to look to learn how to implement such a ...
23
votes
2answers
4k views

What are the possible ways of visualizing a 4D function in Mathematica?

I have a function $F$ that maps the xyz space to a set of reals, more clearly: $c = F[x,y,z]$ Where $c$,$x$,$y$ and $z$ are reals. What are the possible ways of visualizing this 3d function in ...
4
votes
2answers
142 views

Get DownValues that do not involve patterns?

Say I have a function with a few definitions that also implements memoization: f[x_] := f[x] = x^2 f[x_, y_] := f[x, y] = x^2 + y^2 I then apply the function to ...
10
votes
5answers
541 views

Best way to modify values in a list of rules?

Recently I had to solve a problem similar to this: Let's say I have a list of list of rules ...
3
votes
1answer
188 views

Evaluation order of Button[]'s action

it looks like it should be well known issue but I haven't found answer anywhere. Please tell me why the result (after clicking) of this: ...
15
votes
2answers
434 views

Why use Column with Rows instead of Grid?

In general, what are the advantages of using Grid versus a combination of Column and Row? Is Grid better in some situations but not others? For example, is there any reason why one would do this: ...
3
votes
1answer
694 views

How to label the Vertex and, or Edge labels with their weight

I noticed that the Mathematica 9.0 documentation only mentions the usage of "Name" to label the vertexlabel or edgelabel in the Graph. Is there an option to use the Weights automatically just as ...
10
votes
1answer
255 views

Forming Cone with Tube fails to work in version 9.0.1

I use two different radii in a Tube expression to draw a cone. I know for a fact that this worked in Mathematica 8, but when I reevaluated my code in versio 9.0.1 ...
41
votes
3answers
5k views

Image processing: Floor plan - detecting rooms' borders (area) and room names' texts

Here is a simple building floor plan. I would like to derive the rooms as (rectangular) components and the names of the rooms. This is very common representation of building floor plans. The ...
15
votes
1answer
2k views

Compare C++ Standard Library's Mersenne Twister with Mathematica's Mersenne Twister

The C++ standard library does contain a set of random distribution classes, among other things a Mersenne Twister engine. What I'd like to do is to generate the same random number distribution, using ...
2
votes
1answer
86 views

Plot axes invisible when projected

When I save plots made in Mathematica in PDF format and then insert them in a presentation (e.g., in Powerpoint), the plot axes are invisible in the picture created by the projector. Is there a way to ...
17
votes
3answers
873 views

How to clear parts of a memoized function?

I have a function of two variables, e.g.: f[a_, b_] := f[a, b] = something f[a - 1, b - 1] etc With the above code I used the concept of memoization to speed up ...
9
votes
0answers
224 views

Is there a way to teach integrate new solutions?

I have an integral which I can solve, but integrate cannot: ...
3
votes
2answers
149 views

An issue with formulas typesetting in Grid & Column

I tried to construct a small sheet with text and equations presented in a convenient publishing form, using Column: ...
15
votes
2answers
265 views

How do I get a list of allowed values for an option?

When using Mathematica how can I get a list of the allowed values of an option? As an example I can use the Options command as follows - ...
1
vote
1answer
296 views

EventHandler {“MouseDown”, 1} with PassEventsDown -> True not working as expected

I want my EventHandler to respond only to left mouse clicks and pass the right mouse click to the built in event handler. I have tried ...
11
votes
3answers
735 views

How to play microtonal music using Mathematica?

I am trying to model microtonal music using Play. I have only partial success because it takes such a long time to make some sound. Could you please have a look ...
0
votes
2answers
403 views

Integrating hat functions

I am trying to integrate a hat function for a project that I am doing and have found a method to do so but I find it sloppy. Currently I have the basis function ...
3
votes
2answers
328 views

How can I get WhenEvent to recognize criterion I specify?

Using NDSolve I want to solve a differential equation till a quantity which is a function of the dependent variables reaches a certain value. My functions and criteria are complicated, but I am able ...
2
votes
1answer
492 views

Can I customize a TradingChart?

What I would like to do is generate a chart similar to the TradingChart but to have two lines on it instead of the candlestick. The lines I want to plot will look something like this; And what I ...
11
votes
1answer
1k views

Load a Mathematica Package via .Net code

I'm using C# to pass data to Mathematica and return graphs: ...

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