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14
votes
2answers
242 views

What algorithm do the Compress and Uncompress functions use?

Compress and Uncompress are used internally by Mathematica to compress things like 3D data in notebook files - data that I'd like to read independently. Does anyone have any idea if the compression ...
0
votes
1answer
69 views

How to zip a folder? [duplicate]

This straightforward approach doesn't seem to work: In[42]:= cmd = StringSplit@"zip -r ~/data.zip ~/test/*" In[43]:= RunProcess@cmd Related: How can I ...
6
votes
1answer
327 views

How to correctly import data zipped with the “deflate” algorithm?

I'm writing an importer for the GIFTI file format. The details of the format are not particularly important, but the basic idea is that it is a relatively simple XML file which includes binary arrays ...
5
votes
1answer
213 views

HOWTO encode/decode large chunks of Mathematica code/results e.g. for posting on sites?

At times, we as questioners would like to post huge Mathematica-expressions to websites (e.g. mathematica.stackexchange.com), or have an easy way to get such code from a site. Above a certain size, ...
8
votes
2answers
144 views

Compress uses too much memory and sometimes crashes the Kernel

Using Compress is a good idea to save memory when working with large expressions. The problem is that Compressing large ...
4
votes
0answers
100 views

Monitor progress of ZIP file extraction

Importing a ZIP file containing potentially many individual files in a (custom) format using Import[filename, {{"*"}, "Gaussian"}] takes quite a while. How can I ...
2
votes
0answers
430 views

Is there a way to use video codecs for avi files in Mathematica?

I would like to use Mathematica to create compressed .avi video files from image sequences. I read the documentation on .avi but couldn't find a solution. In the documentation it says: ...
0
votes
1answer
884 views

Union::normal: Nonatomic expression expected when using Uncompress

I saved a expresion to a file like this Export["file.dat",Compress@myExpression]; Then (i don't know why) when I import the file i get the compressed expresion ...
15
votes
4answers
1k views

Plotting data points: Optimizing size and visuals

The following problem is one that may have showed up to you while plotting a large data collection. Suppose you have a data set of say 1 million points. ...
10
votes
3answers
611 views

DataEncoding and compression in HDF5 format

I would like to export data in HDF5 format with Mathematica 9. The Mathematica manual about Import and Export of this format can be read here. As I'm dealing with large arrays, export often lead to ...
7
votes
2answers
558 views

DatabaseLink`: MySQL query with client/server compression

I'm trying to reduce transfer time when accessing rows of a mysql table over a network, where each row has a lot of data. Is there a way to enable client-server compression when accessing a mysql ...
3
votes
2answers
100 views

How to uncompress only the compressed elements in a matrix

I have data in a rectangular structure – something like matrix={{a,b,c},{d,e,f},{g,h,i}}. The problem is that some of the columns consist of uncompressed data and ...