All Questions
89,798
questions
3
votes
1
answer
481
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:
...
- 10.7k
7
votes
3
answers
844
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 ...
- 173
7
votes
4
answers
1k
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 ...
- 173
16
votes
4
answers
2k
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 ...
- 34k
9
votes
1
answer
214
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 ...
- 1,162
42
votes
2
answers
2k
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:
...
- 10.7k
12
votes
1
answer
918
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. ...
- 15k
10
votes
2
answers
515
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 ...
- 15k
20
votes
2
answers
857
views
Using several anonymous functions mixed together
This works:
list // BarChart[#[[2]], ChartLabels -> DateString @@@ #[[1]], ChartStyle -> "Pastel"] &
This doesn't:
...
- 69.5k
22
votes
4
answers
762
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
...
- 18k
13
votes
3
answers
861
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?
...
- 477
39
votes
5
answers
22k
views
9
votes
2
answers
607
views
12
votes
2
answers
2k
views
Stream CSV or TSV files
RAM limitations make import impractical for large CSV files. Is it possible to Stream CSV correctly?
str = OpenRead["EU.csv"];
Read[str, "CSV"]
Read::readn: ...
- 1,201
53
votes
6
answers
11k
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 ...
- 1,412
3
votes
2
answers
340
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 ...
- 15k
26
votes
6
answers
7k
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 the ...
- 7,680
7
votes
1
answer
1k
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 ...
- 14.2k
16
votes
3
answers
9k
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 ...
- 711
5
votes
2
answers
1k
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,
...
- 185
45
votes
6
answers
3k
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 ...
- 10.9k
7
votes
4
answers
2k
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 ...
- 7,046
43
votes
7
answers
8k
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:
...
- 24.2k
19
votes
5
answers
4k
views
Numerical underflow for a scaled error function
I calculate a scaled error function defined as
f[x_] := Erfc[x]*Exp[x^2]
but it can not calculate f[30000.]. ...
- 193
4
votes
3
answers
3k
views
Integrating with multiple indicator functions
I am trying to calculate an integral involving multiple indicator functions, such as:
$$ h(u,v,w) = -\int_0^1 J^{\prime\prime}(s) (I_{(0,s]}(u) - s)(I_{(0,s]}(v) - s)(I_{(0,s]}(w) - s)\, dF^{-1}(s)$$...
- 141
6
votes
1
answer
315
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 ...
- 63
15
votes
1
answer
2k
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
...
- 33.7k
37
votes
7
answers
8k
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 ...
- 7,680
56
votes
5
answers
11k
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 did ...
- 7,419
60
votes
4
answers
10k
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])
...
- 971
7
votes
1
answer
443
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 ...
- 655
10
votes
1
answer
279
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 ...
- 8,641
14
votes
2
answers
563
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 ...
- 46.4k
20
votes
3
answers
8k
views
Derivative of real functions including Re and Im
When deriving functions using Re, Im or Arg (and probably some other functions as well), ...
- 19k
8
votes
1
answer
339
views
Module variable scoping in Scheduled Tasks?
I ran across a scoping puzzle while experimenting with ScheduledTasks, and I'd be grateful for an explanation from the sages here. I found a workaround by intuitive horse sense, but was unable to ...
- 8,641
16
votes
1
answer
922
views
Is it possible to colorize brackets in the notebook editor to see matches more easily?
I've seen that if I click on a square bracket [, I can then use "Check Balance" in the right click menu to see where the matching bracket is.
Is there a way to see ...
- 6,288
14
votes
3
answers
2k
views
How to evaluate the $0/0$ type limit in Mathematica?
When I use Limit to evaluate the limit
$$\begin{align}\lim_{k \to 0} \frac{ (k+2)(\alpha^2 - \sqrt{\alpha^4 + k}) + k}{\alpha^2 - \sqrt{\alpha^4 + k} + 2 k}\end{...
- 141
9
votes
3
answers
440
views
Can this code be written in a more functional style
Referencing this question, I wonder if the following code can be written more concisely using a functional style, i.e. without For loops or ...
- 34k
12
votes
6
answers
11k
views
Notation of partial derivative
I want to write partial derivatives of functions with many arguments. Why is it that when I type
f[x,y] ctrl+6 (0,1)
it turns out to be bad syntax? The output of
...
- 7,046
11
votes
2
answers
1k
views
Handling vector comparisons in "Piecewise" function
Is it possible for the Piecewise function to process a vector comparison? For example, my input vector is
x={0,1,2,3,4}
I would like to define a function that ...
- 163
4
votes
4
answers
2k
views
recursively solve equation and saving the values
I am new to Mathematica. I am trying to recursively solve an equation and saving the values into a Table. Since I need the real solutions only I use ...
- 141
17
votes
4
answers
1k
views
How to determine the convex hull of some text?
How can I get the co-ordinates of the convex hull of a piece of Text?
- 1,700
9
votes
1
answer
729
views
Way to find color at a point in a Graphics?
I need to figure out a way to find out the RGB color value at a certain coordinate in a Graphics object. The Graphics object I am dealing with is continually Dynamically updated, so it is made of ...
- 185
7
votes
1
answer
754
views
Color linear interpolation of ParametricPlot3D
I am looking for any ideas about how to colorize an ellipsoid with a custom gradient style or by a Blend function. I would like to colorize ellipsoid as follows:
...
- 73
8
votes
1
answer
260
views
How do I re-direct FilePrint's output?
I recently wanted to use FilePrint to print the contents somewhere else but in the notebook I was using. However, the obvious-seeming solution doesn't work at all:
...
- 18k
3
votes
0
answers
127
views
How do I direct output to a specific notebook or cell? [duplicate]
Possible Duplicate:
How to pipe a stream to another notebook?
Is there any way to create a stream so that all output to the stream (from Write or something ...
- 18k
34
votes
1
answer
7k
views
Autorotating 3D plots
These days, I have to produce quite a few 3D surface plots (mostly functions of the type $\rho(\theta,\phi)$ plotted with SphericalPlot3D). To exchange these ...
- 10.7k
9
votes
2
answers
952
views
Function Interpolation with Automatic / Algorithmic Values Mesh
I have an underlying function f(x,y,z) that is computationally intensive, but is smooth and continuous. I'm needing to find the function values along a line in xyz. Currently, I'm calculating f at ...
- 133
5
votes
1
answer
127
views
Changes in Handling of Real Zeros
I recently upgraded from Mathematica 5 to Mathematica 8 and I have a number of notebooks that no longer work correctly. The problems relate to the use of units. I don't need complicated unit ...
- 53
22
votes
4
answers
18k
views
How to change the axes' origin and direction?
I have manipulated an image and want to ListPlot it. However, the result is not to my liking because the conventions for drawing images and plots are different. ...
- 1,700