# All Questions

314 views

### Find names of the functions defined in a file

Lets say I have a file named file.m that contains: test[] := ( Print["test"] ) How would I go about extracting the function ...
394 views

### Combining Image3D and Graphics3D

I want to combine an Image3D and a Graphics3D using Show. Here is the code: ...
271 views

### Unencoding encoded URLs in a function

Is there a built-in function for decoding encoded URLs in Mathematica? I would like to convert an encoded URL, for example ...
210 views

### Why does array packing in Table behave like this?

Consider the following example, which generate two identical arrays. Why sometimes the array is packed and sometimes it doesn't? And why they perform differently? Here the arrays are packed: ...
394 views

### How to generate a matrix group?

I have three $7\times 7$ matrices (with real entries, lots of zeros) and I'd like to check if they generate a finite group (or, more precisely, if the group they generate is of precise order). Would ...
649 views

### How to change an expression to Fortran90 form?

I have a large expression produced by Mathematica. To use this expression in my Fortran program I need to change it to a Fortran90 form. I am not satisfied with the ...
282 views

### How to change brackets in TraditionalForm output

I'm trying to improve TraditionalForm's output by using different brackets when there are more than one. For instance, instead of $u(v(r(b))))$, I'd like to get ...
793 views

### Dynamic Graph visualization

I'm working on a C++ library that will be used to construct and study certain graphs (as in a set of connected vertices, not a function plot). These graphs will be dynamic in nature (and can ...
338 views

### How to remove ticks?

I wanted to remove the Ticks in my coding but i can't. Here when i try to remove the Ticks the number also gone. I need numbers ...
394 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 ...
247 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 ...
172 views

My code: ...
633 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: ...
546 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 ...
578 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 ...
2k views

### Inverse of a complicated function

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

### how to simplify symbolic integration

The following is the code: ...
705 views

### How to find the smallest root

I have a continuous, differentiable, monotonic, bounded function called F[t]. If t -> Infinity then ...
565 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? ...
981 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 ...
143 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, ...
838 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 ...
113 views

### How to transpose x and y axes on a LogPlot?

Consider the following simple LogPlot: LogPlot[Exp[x],{x,0,5}] Is there a nice way to switch the axes of a LogPlot? I'm aware that plotting the inverse ...
257 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 ...
238 views

### How to use Undocumented Functions Prism, Tetrahedron and Hexahedron

Taking a look at this question and this one, I checked to see if Mathematica really does not have a Prism primitive. To my surprise the function ...
239 views

### Map of Specific US States? (Isolated)

My question here is fairly basic, and I'm sure I'm overlooking something basic. I know about CountryData for creating shapes of entire countries, and it works, to ...
337 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 ...
91 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 ...
452 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 : ...
121 views

### Possible bug with FourierTransform linearity

Each component is easily transformed but the sum is not: FourierTransform[f''[x], x, k] FourierTransform[f'[x], x, k] ...
285 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 ...
495 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 ...
560 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, ...
152 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 ...
365 views

### Getting clearer StreamPlot output

When I do a StreamPlotof a rather complicated pair of differential equations, it loses some details. For example: ...
126 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))] ...
143 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 ...
484 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: ...
226 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 ...
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 = ...
176 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. ...
615 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 ...
162 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 ...
615 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: ...
286 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: ...
893 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: ...
417 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: ...
357 views

### BoxWhiskerChart with logarithmic axes

I would like to make a following chart Ideally I would also like to control the boxes position on a logarithmic x-axis. Some inspiration how to do the latter may be found in the answer to my ...