# All Questions

1k views

### Histograms with pre-counted data

I've got some large data sets which have been counted but not binned already - essentially, a list of pairs of values (not bins) and counts.* (Or, equivalently, it's been binned into too-small bins.) ...
346 views

### Dialog crashes Mathematica

I have some dialog windows in a GUI of which one regularly crashes the kernel. I managed to focus on this particular piece of code, though I don't really know what causes the crash: ...
1k views

### ArcTan expressed as a radian fraction?

This type of answer is what I'm looking for: In[58]:= ArcTan @ 1 Out[58]= π/4 This is what mathematica gives me: ...
848 views

### Importing HDF5 with compound data

I am looking to Import HDF5 data with compound data. It appears, at least from what I read, that Mathematica 8.0.4 (and previous versions) does not support reading ...
4k views

### Understanding CDF

Update Since more and more issues are revealed as I venture deeper into the world of CDF, I decided to make this thread more general and hopefully more useful. I know posted my findings as an answer, ...
1k views

### Animating a Voronoi Diagram

edit: Excellent answers have been provided and I made an animation which is suitable for my use, however, all the examples rely on bitmap/rasterized data; is there a vector based approach? I would ...
582 views

### Expression evaluation inside of FindRoot inside a Compiled Function

I'm trying to get some performance increase out of my own implicit differential equation solver using Compile[]. The uncompiled function is of the following form: ...
376 views

### Extracting equations from Piecewise expressions

Say I have a PDF: PDF[LogNormalDistribution[1.75, 0.65], x] Calculating it, Mathematica gives me an expression that looks like this: I want to extract the ...
267 views

### How to set the return type of a compiled function? (Compile::noinfo warning)

I have simple function I would like to compile, but I get a warning and a call to MainEvaluate. I would like to avoid both. ...
707 views

### How to use local variables with indices in a Mathematica Block environment?

I have the following code: Subscript[f, i_][x_] := Block[{a}, Subscript[a, i] = 3 x; Subscript[a, 1] ] If I evaluate for example ...
229 views

### Usage displays properly only after second call

If I have a usage message containig two-dimensional stuff (subscripts or formulas) and I call the usage, then sometimes I get an improperly formatted output enclosed in "...". Linebreaks are gone, but ...
781 views

### Managing formatted usage messages in Wolfram Workbench

We have numerous packages (defined in .m files) that we maintain and develop in WolframWorkbench (2.0), and in those packages, we use the traditional method of ...
185 views

### Is UndirectedEdge[a,b] the same edge as UndirectedEdge[b,a]?

Is UndirectedEdge[a,b] the same edge as UndirectedEdge[b,a]? Then please consider this. ...
298 views

### Why can't D[] be used in place here? [duplicate]

Possible Duplicate: General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it? Beginner question: Why can't I use ...
296 views

### Export long filename truncated

I am seeing a weird behavior on exporting at least one type of file (here, a QuickTime movie) to files with long names. If I do this: ...
400 views

### How to create a list of pre-defined functions?

I would like to create a list of Cauchy distribution pdf's, having different locations of their maxima, and being multiplied by different factors; then I'd like to calculate those functions' values ...
464 views

### Stationarity tests

I have the Time Series package and Mathematica 8. In the package, there is the function 'StationaryQ' to test the stationarity of a known model. Is there any function in Mathematica to test the ...
1k views

### Printing exported PDF graphics fails (version 8)

When I export even simple graphics, say, a DateListPlot to PDF under Windows, it refuses to print on any of the printers at work. Acrobat (Reader X) throws three ...
152 views

### Accept Infinity as an Integer argument

I have the following function, albeit contrived: Foo[x_Integer] := Module[{i}, i = 1; While[i <= x && i <= 10, i++]; i - 1 ]; I am ...
1k views

### My donut has holes in it!

More than one hole, I mean… I’m trying to export from Mathematica into the X3D format, with the longer term goal of generating 3D figures for PDF inclusion. But I'm stuck at the first step: ...
342 views

### Mathematica implementation of Earth Movers Distance?

Has anyone implemented in Mathematica the Earth Mover's Distance (EMD)? A concept dating back to Monge 1871, used to compare histograms and images, e.g., the CIEDE2000 Color Difference algorithm. ...
216 views

### Cases[data,Colon[key,_]] vs. Cases[data,key:_] toward XPath, XQuery

Exploring methods to index and search tree-structured key:value pairs via named-entity index (key paths) as opposed to Position-based indexing. Using Rule as ...
340 views

### Using several anonymous functions mixed together

This works: list // BarChart[#[[2]], ChartLabels -> DateString @@@ #[[1]], ChartStyle -> "Pastel"] & This doesn't: ...
441 views

### Getting lengths of sublists that sum to more than one

I have a long list of numbers, and I'm interested in finding the length of each sublist that totals to more than 1, so for the list ...
216 views

### Exporting and reimporting a list of lists changes the dimensions

Could anyone explain to me what in the world is going on here and please help me in reading in dummy.dat properly? ...
5k views

### Plotting Error Bars on a Log Scale

I have a plot with ErrorListPlot ...
203 views

...
561 views

### Stream CSV files

Ram limitations make import impractical for large CSV files. Is it possible to Stream CSV correctly? ...
4k views

### Finding real roots of negative numbers (for example, $\sqrt[3]{-8}$)

Say I want to quickly calculate $\sqrt[3]{-8}$, to which the most obvious solution is $-2$. When I input $\sqrt[3]{-8}$ or Power[-8, 3^-1], Mathematica gives the ...
188 views

### Rotate doesn't work with BarChart and BoxWhiskerChart

Rotate@BarChart[RandomReal[1, {4, 5}], ChartLayout -> "Percentile"] Even though the FullForm generated by BarChart is Graphics expression, Rotate has no ...
2k views

### Fixing quirky typesetting in plot labels

Consider this example plot. Plot[ 1-Exp[-x], {x,0,3}, AxesLabel->{"thickness (μm)","power density (W/m^2)"} ] Let us hold the typographical quality of ...
529 views

### How do I calculate the probability of reaching mean residual life

I need to understand the Survival Analysis concept of "mean residual life (MRL)" and calculating probabilities for reaching it. From another discussion: The MRL at time t is the mean additional ...
1k views

### Assigning values to a list of variable names

As part of a calculation I need to do something like this Evaluate[{aaa, bbb, ccc}[[ index]]] = {1, 2, 3, 4, 5} so if index is ...
258 views

### Plotting contours of a function for different values of a parameter

I want to draw a picture of $(x-t)^2 + (y-t^2)^2 - t^2$ in $xy$ plane, with different values of $t$. I did it in a very silly way , namely, ...
1k views

### How to visualize/edit a big matrix as a table?

Is it possible to visualize/edit a big matrix as a table ? I often end up exporting/copying big tables to Excel for seeing them, but I would prefer to stay in Mathematica and have a similar view as in ...
315 views

### Delayed evaluation of assignment

I have a set of PDE's that depend on parameters. They depend on many parameters, but for simplicity we can here assume that they depend only on one, say a. I want ...
1k views

### How to apply or map a list of functions to a list of data?

Say I have a group of functions: f1[a_] := a * -1; f2[a_] := a * 100; f3[a_] := a / 10.0; and some data in a list: ...
1k views

### Numerical underflow for a scaled error function

I calculate scaled error function defined as f[x_] := Erfc[x]*Exp[x^2] but it can not calculate f[30000.]. ...
455 views

### Integrating with multiple indicator functions

I am trying to calculate an integral involving multiple indicator functions, such as:  h(u,v,w) = -\int_0^1 J^{\prime\prime}(s) (I_{(0,s]}(u) - s)(I_{(0,s]}(v) - s)(I_{(0,s]}(w) - s)\, ...
264 views

### Getting Integrate to perform numerical integration

I am trying to calculate the mutual impedance of two antennas which is just a big integral. I defined my function in terms of my variable, but when I execute it, Mathematica runs for a while and then ...
428 views

### Finding a Specific Line in a Package

In a package I am developing, I accidentally left this line Protect[ uncompleted prior to running the package. Mathematica produced this error message ...
2k views

### Importing a large Excel file

I'm trying to import a simple Excel file containing 94,000 rows and 52 columns of various types, mostly Reals. It's a 38-MB file. I get this super helpful error ...
3k views

### How can I extract data points from a black and white image?

Consider the following graph (source): Is there any way to extract the data points from this image in a semi-automatic way? I have seen, and tried the methods suggested in this question, but they ...
744 views

### Can I simplify an expression into form which uses my own definitions?

This seems like a simple thing to do, but I couldn't find anything relevant from Mathematica documentation. So suppose I have an expression: a*b/(a + a*Cos[a/b]) ...
257 views

### Setting \$RecursionLimit across all parallel kernels

I'm trying to optimize an elliptic curve factoring method by running it in parallel. There is a recursive step which required me to set the recursion limit higher than 256, however when I try and run ...
171 views

### Difficulty catching thrown errors in asynchronous tasks

In this Question, Leonid explained that module variables can get garbage collected from a chain of asynchronous tasks unless their Temporary attribute is cleared ...
305 views

### Split a Unicode string maintaining uppercase characters

I want to split a string according to a predefined set of substrings (lowercase), though the actual text can contain uppercase characters anyplace. The task is to find the matches, longer preferred ...
2k views

### Derivative of real functions including Re and Im

When deriving functions using Re, Im or Arg (and probably some other functions as well), ...