13
votes
5answers
664 views

How to thread a list

I have data in format data = {{a1, a2}, {b1, b2}, {c1, c2}, {d1, d2}} Tableform: I want to thread it to : ...
12
votes
4answers
3k views

Minimizing a function of many coordinates

I'm trying to obtain a series of points on the unit sphere with a somewhat homogeneous distribution, by minimizing a function depending on distances (I took $\exp(-d)$). My points are represented by ...
15
votes
2answers
1k views

FindFit returns Infinity::indet error when data contains {0,0}

Let's consider the following data: data = Table[{q, 2*q^2}, {q, 0, 2}]; and then, do a very simple fitting to this data: ...
12
votes
1answer
325 views

Function as an option to a function

I am new to mathematica ,so this question may seem a little naive. I know how to use the option as an argument to a function, we can define an option by using ...
4
votes
1answer
224 views
9
votes
3answers
2k views

Saving high-quality graphics through commands

Say I make and display a graph in a Mathematica notebook: graph = CompleteGraph[100] If I drag the corner of the graph to increase its size, and then save it to ...
9
votes
1answer
445 views

GeoDirection and GeoDistance Memory Leaks: How to Recover the Memory?

The functions GeoDirection and GeoDistance have memory leaks. To see this, run the example functions below and watch as the Physical Memory Available in the Windows Task Manager, Performance tab, ...
4
votes
1answer
256 views

How do I use the result of Solve in a function definition?

I'm trying to adapt the following piece to the part where PowerF is a function of amax. ...
24
votes
3answers
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.) ...
6
votes
1answer
355 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: ...
4
votes
2answers
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: ...
9
votes
3answers
945 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 ...
44
votes
3answers
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, ...
27
votes
2answers
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 ...
5
votes
2answers
625 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: ...
10
votes
4answers
393 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 ...
5
votes
2answers
292 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. ...
9
votes
3answers
777 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 ...
13
votes
1answer
233 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 ...
14
votes
4answers
841 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 ...
17
votes
1answer
189 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. ...
7
votes
3answers
301 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 ...
3
votes
1answer
314 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: ...
7
votes
3answers
435 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 ...
5
votes
2answers
482 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 ...
16
votes
4answers
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 ...
9
votes
1answer
153 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 ...
38
votes
2answers
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: ...
9
votes
1answer
362 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. ...
8
votes
2answers
227 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 ...
14
votes
2answers
366 views

Using several anonymous functions mixed together

This works: list // BarChart[#[[2]], ChartLabels -> DateString @@@ #[[1]], ChartStyle -> "Pastel"] & This doesn't: ...
16
votes
4answers
446 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 ...
11
votes
1answer
233 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? ...
21
votes
3answers
5k views

Plotting Error Bars on a Log Scale

I have a plot with ErrorListPlot ...
6
votes
1answer
608 views

Stream CSV files

Ram limitations make import impractical for large CSV files. Is it possible to Stream CSV correctly? ...
32
votes
6answers
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 ...
3
votes
2answers
193 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 ...
21
votes
6answers
3k 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 ...
7
votes
1answer
565 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 ...
6
votes
3answers
2k 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 ...
5
votes
2answers
278 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, ...
30
votes
6answers
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 ...
4
votes
3answers
333 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 ...
27
votes
7answers
2k 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: ...
12
votes
4answers
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.]. ...
4
votes
3answers
494 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)\, ...
6
votes
1answer
276 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 ...
10
votes
1answer
486 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 ...
14
votes
2answers
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 ...

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