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What is exactly the base pointer and stack pointer? To what do they point?
...egisters stay where they are, only their value is sent to the RAM from the CPU. In the amd64 mode, this gets a bit more complex, but leave that to another question.
– wigy
Jan 20 '17 at 10:42
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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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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 ...
How can I repeat a character in Bash?
...llowing are timings taken on a late-2012 iMac with a 3.2 GHz Intel Core i5 CPU and a Fusion Drive, running OSX 10.10.4 and bash 3.2.57, and are the average of 1000 runs.
The entries are:
listed in ascending order of execution duration (fastest first)
prefixed with:
M ... a potentially multi-cha...
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...
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
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How can bcrypt have built-in salts?
...ext.
What is more important : There is no hashing in this process, rather CPU expensive encryption - decryption. thus rainbow tables are less relevant here.
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How much faster is C++ than C#?
...ter will be competing with your code for instruction and data cache in the CPU. We know that cache dominates when it comes to performance and native languages like C++ do not have this type of contention, by definition.
a run-time optimizer's time budget is necessarily much more constrained than th...