7
votes
3answers
405 views

How to Gather a list with some elements considered unique

I have a list of the form: list={{0,...},{1,...},{1,...},{0,...},{3,...},{3,...},{0,...},{0,...},{5,...},{5,...},{5,...},{0,...},{5,...},{0,...},...} So when we ...
7
votes
1answer
248 views

How to wrap this dynamic code inside a Manipulate?

My goal is to set up a Ising-type simulation, where many fast simulation steps are done in the background, and a visualization of the current state is displayed as the simulation evolves, being ...
7
votes
1answer
173 views

Is this a good way to assign a Solve result to a function?

My code: ...
7
votes
3answers
648 views

How to rotate TickMarks in DateListPlot?

Is there a way to rotate TickMarks in DateListPlot to avoid overlap, eg: Part of the code used to generate this is: ...
7
votes
2answers
551 views

Simplifying the derivative of $|x|$

Context In[855]:= D[Abs[x], x] /. x -> 1 Out[855]= Derivative[1][Abs][1] In[856]:= D[x, x] /. x -> 1 Out[856]= 1 Question Why is ...
7
votes
6answers
596 views

Using a built-in symbol as a variable

I want to produce a Mathematica Computable Document in which N appears as a variable in my formulae. But N is a reserved word in ...
7
votes
2answers
2k views

Inverse of a complicated function

Mathematica is struggling to find the inverse of this function f(r): ...
7
votes
3answers
1k views

how to simplify symbolic integration

The following is the code: ...
7
votes
1answer
731 views

How to find the smallest root

I have a continuous, differentiable, monotonic, bounded function called F[t]. If t -> Infinity then ...
7
votes
1answer
568 views

Efficiently deleting rows in many large text files

I have 500 text files each of about 200000 rows. I need to delete one row in each of them as fast as possible (later such operations will repeat). What is the best way to do this with Mathematica? ...
7
votes
4answers
1k views

Force function to make assumptions about its input variables in Mathematica

I'm trying to force a Mathematica function to make an assumption about its input variables. In my case, I'm trying to define a function to return the pdf of a Gaussian. But let's use a simple toy ...
7
votes
1answer
144 views

Organizing similar datasets using Contexts or otherwise

I often import several long time series to analyze something about a city. When I have multiple cities, I use contexts. As a simple example, ...
7
votes
3answers
639 views

Efficient image Import

I have several sets of 20 images I need to import. Each time they have different categories. "Name"<>"Cat"<>"No" Electric B 1 for example. I need to create lists that contain the images ...
7
votes
1answer
844 views

How do you get high resolution plots in applications using the Mathematica MathService?

This is for Mac users only using MathService (MathService it seems, given that it was created back in 2004, is a power pc code and requires Rosetta to run on Intel). If I type a plot command in ...
6
votes
1answer
104 views

Can't plot rotated region

I was experimenting with the code from this question when I ran into another problem with regions. ...
6
votes
2answers
261 views

How to color edges of a graph which has multiple edges connecting certain vertices

I'm studying BIBD(Balanced Incomplete Block Design) and want to draw some graphs by coloring their blocks in different colors, respectively. A block is a collection of edges (or vertices). For ...
6
votes
1answer
347 views

Find the eigenvector associated with the smallest eigenvalue, not smallest in magnitude

I am trying to find the eigenvector of a $20000 \times 20000$ sparse matrix associated with the smallest eigenvalue. I realized that the smallest eigenvalue might be negative; for example, if the ...
6
votes
1answer
94 views

How to understand shared passing of a MTensor in LibraryLink?

According to the documentation, there are four different type of memory managing when passing a MTensor with LibraryLink: Automatic, "Constant", "Manual" and "Shared". The Automatic and "Manual" is ...
6
votes
3answers
461 views

How to randomly erode a 3D distribution of points with Mma 7.0?

Suppose we have a 3D distribution of points, like the spherical ball example below : ...
6
votes
1answer
75 views

Is it possible to find a function from first few terms in the expansion

Is it possible to find a function if first few terms of the expansion is known. For example if I have this series $f(x)=\frac{k^3 x^2}{6}-\frac{k^5 x^4}{120}+\frac{k^7 x^6}{5040}-\frac{k^9 ...
6
votes
1answer
293 views

Having trouble fitting data using NonlinearModelFit

I'm trying to fit data = {{2002, 45000}, {2004, 90000}, {2005, 120000}, {2013, 211000}}; to an exponential function ...
6
votes
9answers
518 views

combining and comparing lists

I have 2 lists (of lists), where most of the contained lists match. That is, the lists contained in list1 mostly match the lists contained in list2. In this simplified example each of the inner ...
6
votes
4answers
632 views

Removing empty sets from lists

If I had a list, say, names= {"Andy", "Bob", "Carly", "Sandy", "Jeff", "Tim", "Tom", "Zach"} and I decide to pick a characteristic only a certain of them have, ...
6
votes
1answer
154 views

The third argument of the Root function

Consider the roots of an arbitrary indecomposable polynomial: sol = Solve[x^5 + 2 x + 1 == 0, x] The returned expression is ...
6
votes
1answer
376 views

Getting clearer StreamPlot output

When I do a StreamPlotof a rather complicated pair of differential equations, it loses some details. For example: ...
6
votes
1answer
180 views

Behavior of Graphics`Mesh`InPolygonQ with self-intersecting polygons

Playing around with some of the answers in the question How to check if a 2D point is in a polygon? I noticed that: Graphics`Mesh`InPolygonQ[poly,pt] Displays ...
6
votes
3answers
127 views

How to simplify my expression to the style of “a+b*I”?

How to simplify my expression to the style of "a+b*I"? Expand[(E^(I θ) (-1 + E^(I n θ)))/(-1 + E^(I θ))] ...
6
votes
4answers
145 views

Hold expression with RandomInteger

One more question for today: I'm trying to show two random integers with a plus (+) sign between them, in an unevaluated form. I know how Hold and HoldForm work, but they hold everything, including ...
6
votes
3answers
792 views

Circular Plot and Circular Histogram

The spherical or circular data arises when we measure data in degree e.g wind direction, clock and compass etc. Then representation of such data we need to plot circular plot, circular histogram and ...
6
votes
3answers
489 views

Expression of uncertainty in measurement.

I have a problem with writing a Mathematica function. I have been requested to show the results of my experiments with the measurement uncertainty (mu) like below: ...
6
votes
1answer
229 views

String pattern search and replacement — it works, but produces error messages only the first time it is called

I defined a function in Mathematica to process a pre-generated string. More specifically, I'd like to process some parts of C codes generated from MMA. Basically what my function does is to expand the ...
6
votes
2answers
1k views

How do you put conditions on indices in a sum?

I'm relatively inexperienced with mathematica, so I apologize if this is a trivial question. I want to take a double sum over a function $f(i,j)$ of two indices, of the form $$ \sum_{i = ...
6
votes
3answers
177 views

Is it possible to Import urls not type “”

These days I often copy urls from Internet Explorer's address bar. When I paste the url into a Mathematica cell it is neither a string nor a expression. ...
6
votes
2answers
627 views

Manipulating plot of random iterated function system fractal

I'm generating the Sierpinski Gasket by implementing a chaos game in mathematica. What I'd like to do is create an interactive manipulation with a slider, whereby moving it forward, plots all the ...
6
votes
1answer
165 views

Importing images from the web using ImportString & URLFetch

I can bring images from the web using the Import command like this: Import["http://blog.wolfram.com/wp-content/uploads/2008/06/se-30.jpg"] Sometimes the web ...
6
votes
4answers
635 views

data visualization on a lattice grid

Is it possible to visualize an array whose elements are angles as actual angles on a lattice grid? E.g., say, if the input is: ...
6
votes
2answers
290 views

How can I find if the number of subsets for a list is very large?

I'm trying to find the following; Subsets[Range[2, 2300], {4}] but my computer gave the following error: ...
6
votes
1answer
120 views

Using enum values with J/Link

How can I pass enum values to a function when using J/Link? What is the correct syntax for typing an enum value? For example, call normalize() using ...
6
votes
6answers
903 views

Image of first quadrant under $f(z)=(z+i)/(z-i)$

I'm able to plot the region where Im[z] > 0 and Re[z] > 0: ...
6
votes
4answers
427 views

How do I display an expression with negative powers?

How do I display an expression with negative powers? Mathematica seems to always invert a term with a negative rational power. None of the following work: ...
6
votes
1answer
301 views

How can I define a function that can accumulate its parameter?

For example, write a function add: add[3] return 3 add[4] return 7 add[10] return 17
6
votes
1answer
276 views

PlotStyle does not work when plotting a non-evaluated list of functions [duplicate]

When a list of functions is passed to Plot in an unevaluated form (e.g. with Through), the result is a plot with single color. ...
6
votes
1answer
206 views

Under what conditions does FinancialData return a ::notent message?

I tried retrieving FinancialData for a few companies but when I tried doing it for NTDOY, I couldn't. As of 25/12/2012, querying ...
6
votes
3answers
198 views

How to rename a built-in function?

I want a built-in function renamed without loss of any properties, I want the shorter name to appear in all results and to be recognized as input. Is it possible?
6
votes
1answer
361 views

BSplineCurve Interpolation

Can I get interpolated values from this B-spline, (shown in red)? ...
6
votes
2answers
133 views

Prevent front-end from reformatting long fractions while editing

I am editing an expression containing wide fractions (typeset with fraction boxes): But if, while editing the equation, the fraction exceeds some threshold (seems to be approximately the window ...
6
votes
1answer
139 views

Problem overloading D[] using UpValues

First I define an entry of UpValues overloading D[] for expressions with head ftest: ...
6
votes
2answers
221 views

How do I Export through a standard system file save dialog activated by a Button?

As near as I can tell, Export cannot be configured through arguments or options, to present a standard system file save dialog to the user, so that he can specify a ...
6
votes
2answers
188 views

Can Tuples help simplify this?

I have a list {1, 2, 3, 4} and wish to form {{{1,2},{3,4}}, {{1,3},{2,4}}, {{1,4},{2,3}}} I ended up doing it manually ...
6
votes
3answers
357 views

How can I stop the blinking when rotating a Graphics3D? [closed]

I wrote a function interactiveDesign that returns different Graphics3D items in a list. Then I call the function ...

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