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Very large matrices using Python and NumPy
...L-like GROUP BY aggregation at 1,000,000 rows/second. Not bad for a Python-based solution!
Accessing the data as a NumPy recarray again is as simple as:
data = table[row_from:row_to]
The HDF library takes care of reading in the relevant chunks of data and converting to NumPy.
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In Java, what is the best way to determine the size of an object?
... with piles of data rows. I give the user a summary of the number of rows based on types of data, but I want to make sure that I don't read in too many rows of data and cause OutOfMemoryError s. Each row translates into an object. Is there an easy way to find out the size of that object programm...
Why would you use an ivar?
..., gender (enum), and age (unsigned) of its owner, as well as a balance (int64_t). An account object has an init method and a compare: method. The compare: method is defined as: Female orders before male, names order alphabetically, young orders before old, balance orders low to high.
Actually there...
How to find out what type of a Mat object is with Mat::type() in OpenCV
...e CV_32S: r = "32S"; break;
case CV_32F: r = "32F"; break;
case CV_64F: r = "64F"; break;
default: r = "User"; break;
}
r += "C";
r += (chans+'0');
return r;
}
If M is a var of type Mat you can call it like so:
string ty = type2str( M.type() );
printf("Matrix: %s %dx%d ...
How to Calculate Execution Time of a Code Snippet in C++
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You can use this function I wrote. You call GetTimeMs64(), and it returns the number of milliseconds elapsed since the unix epoch using the system clock - the just like time(NULL), except in milliseconds.
It works on both windows and linux; it is thread safe.
Note that the gr...
Download data url file
I'm playing with the idea of making a completely JavaScript-based zip/unzip utility that anyone can access from a browser. They can just drag their zip directly into the browser and it'll let them download all the files within. They can also create new zip files by dragging individual files in.
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How to compare 2 files fast using .NET?
... and make more sense if you can pre-compute the checksum of the "test" or "base" case. If you have an existing file, and you're checking to see if a new file is the same as the existing one, pre-computing the checksum on your "existing" file would mean only needing to do the DiskIO one time, on the...
Android SDK installation doesn't find JDK
I'm trying to install the Android SDK on my Windows 7 x64 System.
45 Answers
45
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How to play a notification sound on websites?
...Ion.Sound GitHub Page
Advantages:
JavaScript-plugin for playing sounds based on Web Audio API with fallback to HTML5 Audio.
Plugin is working on most popular desktop and mobile browsers and can be used everywhere, from common web sites to browser games.
Audio-sprites support included.
No depende...
Generating Random Passwords
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this method (base 62) is superior than the GUID(base 16) on strength: an 8-char hex string is equivalent to a 4-5 char alphanumeric one
– Jimmy
Sep 10 '08 at 18:51
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