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How do browsers pause/change Javascript when tab or window is not active?
...stribution: setInterval vs requestAnimationFrame
Note: This test is quite CPU intensive. requestAnimationFrame is not supported by IE 9- and Opera 12-.
The test logs the actual time it takes for a setInterval and requestAnimationFrame to run in different browsers, and gives you the results in the ...
JSON and XML comparison [closed]
...erformance reports, conducted by the W3C, as efficiency and low memory and CPU footprint, is also a matter for the XML area too: Efficient XML Interchange Evaluation.
Update 2015-03-01
Worth to be noticed in this context, as HTTP overhead was raised as an issue: the IANA has registered the EXI enc...
物联网入门 · App Inventor 2 中文网
...钮，并拖动亮度滑块。LED 应响应开关和亮度变化。
常见问题
扫描不到 Arduino
确认固件已经上传，Arduino 供电正常，手机蓝牙已打开；连接时不要同时运行多个 BLE 实验 App。
连接成功但没有数据
检查连接事件中是否调用了对...
Bash tool to get nth line from a file
...huge, you'd better exit after reading the required line. This way you save CPU time See time comparison at the end of the answer.
awk 'NR == num_line {print; exit}' file
If you want to give the line number from a bash variable you can use:
awk 'NR == n' n=$num file
awk -v n=$num 'NR == n' file ...
Explain the use of a bit vector for determining if all characters are unique
...cause operations with bits are very low level and can be executed as-is by CPU. BitVector allows writing a little bit less cryptic code instead plus it can store more flags.
For future reference: bit vector is also known as bitSet or bitArray. Here are some links to this data structure for differen...
Evaluating a mathematical expression in a string
...rbitrary commands
eval("9**9**9**9**9**9**9**9", {'__builtins__': None}) # CPU, memory
Note: even if you use set __builtins__ to None it still might be possible to break out using introspection:
eval('(1).__class__.__bases__[0].__subclasses__()', {'__builtins__': None})
Evaluate arithmetic expr...
What does it mean to hydrate an object?
... for your current operations. So there's no reason to waste bandwidth and CPU cycles loading, transferring, and setting this data when it's not going to be used.
Additionally, there are some ORM's, such as Doctrine, which do not hydrate objects when they are instantiated, but only when the data is...
How do I replace NA values with zeros in an R dataframe?
...am running these tests on fully numeric dataframes.
Hardware Used
3.9 GHz CPU with 24 GB RAM
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How to append rows to an R data frame
...t(r)
For 1E5 rows (measurements done on Intel(R) Core(TM) i7-4710HQ CPU @ 2.50GHz):
nr function time
4 data.frame 228.251
3 sqlite 133.716
2 data.table 3.059
1 rbindlist 169.998
0 placebo 0.202
It looks like the SQLite-based sulution, although r...
Why does changing 0.1f to 0 slow down performance by 10x?
... sets FTZ (flush to zero) and DAZ (denormal are zero) in the MXCSR, so the CPU never has to take a slow microcode assist for denormals.
– Peter Cordes
Jan 16 '19 at 10:23
add ...