1
vote
2answers
296 views

Importing numerical data from RTF file

This might be a very simple question but I have been struggling with it for a couple of hours, so thought maybe someone here can show me a quick way of solving it. I have a file in rtf format (...
4
votes
1answer
290 views

How could I improve this Central Limit Theorem demonstration speed- and content-wise?

My purpose is to demonstrate the Central Limit theorem by assuming two custom distributions, taking some random samples, calculating their means and ploting the results. Ideally, the histograms should ...
4
votes
2answers
354 views

How to make the computer consider two numbers equal up to a certain precision

My problem is that I have a matrix A and the computer says is not Hermitian (self-adjoint). Then I check which elements make A ...
5
votes
2answers
753 views

Problems with Symbolic summation over unknown values

I'm having some real trouble with Mathematica wrongly evaluating various symbolic sums at the moment. I have this function: $$h_{ij}(x) = \binom{j-1}{i-1}-\sum_{r=0}^{j-x-n-(k+1)/2-1}\binom{r+x+n+(1-...
0
votes
1answer
113 views

Truncate a fractional value to particular number of bits?

If I have a fractional value, how can I truncate (not round) that to a certain number of bits, like 8? For example, for Pi 3.141569265359... the fractional part is 0.141569265359... ...
3
votes
1answer
265 views

Read C-formatted hexadecimal numbers?

I have a lot of 32-bit numbers in hexadecimal symbolized as they are in C (for example, 0x1230abde). How can easily read these in Mathematica?
8
votes
2answers
551 views

No builtin function for bitwise rotation?

There appears to be no builtin Mathematica function for bitwise rotation. Is that true? I suppose I can write my function: ...
3
votes
3answers
100 views

How to get different items in a list to interact to get a result?

I have two lists, for example (the real lists are much longer): list1 = {1, 2, 3, 4, 5, 6, 7}; list2 = {9, 10, 11, 12, 13, 14, 15}; I want to create a single ...
7
votes
1answer
318 views

Limit for Matrix expression

Let's assume that $Q_0$ is $3\times 3$ matrix with $\det Q_0\neq0 $ and $$ Q_{i+1} = \frac{1}{2}\left[ Q_i+(Q_i^{-1})^T \right] $$ I need to find next limit: $\lim _{i \to +\infty}$$Q_i$. In other ...
-2
votes
2answers
626 views

Problem with convert matlab function into mathematica version of euler angle

I've wrote a function that will extract euler angle from matrix according to Matlab's function in AeroSpace toolbox's dcm2angle package file. But not quite right. ...
1
vote
1answer
302 views

Manipulate with variable number of sliders plus variable number of functions

I'm trying to setup a Manipulate where I have a variable number of sliders similar to this one, where every slider controls a function. In my case, there will be an additional slider which sets the ...
3
votes
1answer
372 views

How can I produce a branch cut in a surface plot based made with ListPlot3D?

I need to create some surface plots, based on a function that is computationally expensive (a few minutes per point). The function has some branch cuts. The command ...
1
vote
1answer
116 views

Document settings for online viewing

I'm trying to figure out how to prepare a notebook for NICE online viewing when it's been converted to PDF form. The students I am working with (sadly!) will not be able to use the CDFPlayer to view ...
5
votes
1answer
522 views

Why is Plot3D giving me a surface with gaps?

I am trying to get plot for the band structure for graphene. ...
0
votes
1answer
607 views

How to force Mathematica not to use Erf and DawsonF functions in its output

In ODE solutions Mathemathica uses Erf and DawsonF functions instead of the integral expressions they represent. How can I force ...
0
votes
0answers
67 views

kernel shuts down during listplot [duplicate]

In at least the following situations, I have experienced that the kernel has shut down during evaluation. The thing is that there is no message at all when it shuts down. ...
3
votes
4answers
847 views

I want to calculate the pixel values of an image and export to a standard format

After finishing a few tutorials, I thought I was ready to calculate the pixel values of a large (smaller numbers 20x20 used here) image and export to a standard format (.jpg) but my code doesn't work. ...
0
votes
1answer
98 views

Issues FindRootPlot command

I've had some fun playing around with FindRootPlot for a simple system of equations: ...
0
votes
0answers
103 views

creating some smooth density functions

I would like to create some density functions based on some distance measure $D$. As a base density function lets say I have a Gaussian density $f$ with mean $-1$ and variance $1$. I would like to ...
5
votes
3answers
204 views

Preserving a bijection between arrays when shuffling elements in one array

Imagine I have two lists of elements like the following: listOne = RandomReal[{0,2}, {100,2}]; listTwo = RandomReal[{0,2}, {100,2}]; Let $f: X \to Y$ be a ...
1
vote
1answer
139 views

Bound on number of function evalulations in FindMinimum

I am minimizing a nonlinear constrained problem using FindMinimum. The problem involves about 200 variables and the function is a black-box which cannot be compiled/...
2
votes
1answer
233 views

Writing NDSolve-like functions

I've been using Mathematica for a while now, and there are multiple common tasks that I end up doing. I'd like to learn how to convert them into functions so that I can store them in some file and ...
1
vote
1answer
655 views

Hex Representation in Mathematica and Python

I want to convert a code from Mathematica to Python. I am using the following code to convert a code to hexadecimal, binary and so on: ...
4
votes
2answers
2k views
0
votes
1answer
119 views

Configure initial directory

How can I configure the initial directory? By configure, I mean set it so that when Mathematica starts the initial directory is one of my choosing. By the by, what exactly is the significance of the ...
8
votes
2answers
473 views

How can I get $(r^{1/x})^x$ to simplify to $r$?

Simplify and FullSimplify do not simplify this kind of expression: $(r^\frac{1}{x})^x$. Consider ...
9
votes
5answers
2k views

How to render a 3D ellipsoid with Graphics3D?

With Graphics3D[Sphere[{0, 0, 0}, 1]], I can render a uniform 3D sphere, but how can I render an ellipsoid? I would need to specify the rotation of the ellipsoid ...
5
votes
4answers
424 views

Display a number in Mathematica 9 in periodic form

I want to display a rational number in Mathematica in periodic style. PeriodicForm isn't working anymore. It worked in Mathematica 5 and now I'm using Mathematica 9....
6
votes
1answer
262 views

Iteration process involving several functions

I would like to carry out a following iteration process: Apply function f1[a_,b_,c_,d_] to a starting list l1={a1,b1,c1,d1}, ...
5
votes
1answer
289 views

Omitting singularities from plot by specifying them in range

See the Mathematica 'basic plotting' documentation: http://reference.wolfram.com/mathematica/tutorial/BasicPlotting.html Scroll down to the third plot on that page, which says the following: "The ...
5
votes
2answers
368 views

Provided an array of 2D point clouds, can we quickly replace distance- and index-based cliques of points with their median or mean values?

Imagine I have $N \approx 10^5$ clouds of points in an array of the form: UPDATED ...
5
votes
1answer
128 views

Why DateDifference returns machine number?

Is there any specific reason why DateDifference cannot give an exact number in this case? ...
48
votes
1answer
1k views

Export Code to Pseudocode?

I'm writing a paper and all my code is in Mathematica. The snippets are mostly simple, and consist of loops, maps, variables, and conditionals. I'd like add it to my paper, however, not many academic ...
2
votes
0answers
124 views

Question about Solve

I don't understand what Mathematica is doing to get these solutions. I ask it to solve two equations, the left hand side of both expressions are the same, the right hand sides differ by a ± sign. I ...
2
votes
1answer
127 views

Function to differentiate between date pattern and specific string format

I'd like to write a function that behaves one way when the argument is a Mathematica date, such as {2013,12,15}, or with added hours, minutes and seconds if ...
2
votes
0answers
135 views

How to solve system of differential equations of arbitrary order (symbolic tensors)?

I am interested in solving systems of ODEs symbolicly, keeping things with arbitrary dimensions for clarity. For example, assume that $x, f(x) \in R^N$ and $A \in R^{N \times N}$, how do I solve $f'(...
4
votes
2answers
109 views

Cell copy results in jaggy, aliased output

When I copy a cells by selecting them from the collapse bars on the right, then using the context menu option "Copy", the pasted image of plots is not anti-aliased and in general the text seems to ...
3
votes
3answers
605 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
1answer
121 views

Frontend coloring of Table[x, {x, 0, x}]

I have a small question about how the Mathematica frontend colours in the variables that appear in (wrongly written) iterators. More specifically, I'm intrigued by the colour of the third ...
2
votes
2answers
83 views

Optimize recurrence output

I have recurrence and I need to calculate first $N$ members of the sequence ...
5
votes
1answer
439 views

Symbolic linear algebra

I would like to know how I can ask Mathematica to expand (and simplify) such an expression : $$ (\alpha A + \beta B)^\top (\alpha A + \beta B) $$ where $\alpha,\beta$ are two real numbers and $A,B$ ...
14
votes
3answers
309 views

How do I put my packages into Dropbox

I don't want to necessarily put my packages in Mathematica's $UserBaseDirectory, which is on my local hard drive. Can I somehow tell Mathematica to look for ...
1
vote
1answer
104 views

Evaluating an ItoProcesss function

The following is my Stochastic D.E.: ...
2
votes
0answers
114 views

Error message from V6.0.3 on Mavericks

With Mavericks, everything works fine except saving documents -- then I get this error: Internal self test error MacDialog | c | 2 Fixes? Ideas? Any help appreciated.
2
votes
1answer
267 views

How to create a SparseArray satisfying multiple conditions on Parts and Elements of a Matrix?

I have a matrix m1 of size $3 \times 19$. Rows $1$, $2$ and $3$ represent $3$ different groups, and columns represent $4$ different blocks: block1 - columns $1$, ...
1
vote
1answer
274 views

Mathematica won't simplify multiplication by zero

I'm getting a huge output, but it appears that almost every term should actually be zero, unless I'm misunderstanding the expression. For example, part of the output reads ...
4
votes
2answers
152 views

how to load packages on local computer when using remote kernels

I usually works remotely using kernels on our hpc and front-end on my local laptop. This enable me do relatively large computation within my laptop(IP address of my laptop may change frequently). But ...
4
votes
1answer
199 views

Forcing optimal solution for FindShortestTour

I use FindShortestTour as explained here and it works nicely for a small number of cities. However when I try this with as little as 16 cities, the given tour isn't ...
3
votes
2answers
135 views

Mathematica regex equvalent of \l

In normal RegEx \l will make the character to the right lowercase. However, it seems like the RegEx in Mathematica does not have this functionality. For example <...
12
votes
9answers
1k views

How to partition a list of numbers in two lists of numbers such that each lists elements sums up to the same number?

I have the following list of squares. {1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256} Their sum is $1496$, I want to make two partitions ...

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