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arrayfun can be significantly slower than an explicit loop in matlab. Why?
...s as fast as the fully vectorized version... That was all done on a single CPU. Results for Soln5 and Soln7 do not change if I switch to 2 cores - In Soln5 I would have to use a parfor to get it parallelized. Forget about speedup... Soln7 does not run in parallel because arrayfun does not run in pa...
Are list-comprehensions and functional functions faster than “for loops”?
...ts in this case with Python 3.6.1, Ubuntu 14.04, Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
0:00:00.257703 #Reduce
0:00:00.184898 #For loop
0:00:00.031718 #Map
0:00:00.212699 #List comprehension
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GDB corrupted stack frame - How to debug?
...rame (corrupt stack?)"; I've done something exactly like this in code in a CPU exception handler before, but couldn't remember other than info symbol how to do this in gdb.
– leander
Mar 8 '13 at 19:05
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Are Stored Procedures more efficient, in general, than inline statements on modern RDBMS's? [duplica
...cro level.
Still an advantage?
Not very noticeable at all on the modern CPU, but if you are sending a single SQL statement that is VERY large eleventy-billion times a second, the parsing overhead can add up.
Pre-generated query execution plan.
If you have many JOINs the permutations can grow qu...
How do I verify/check/test/validate my SSH passphrase?
...le slow. Most of the programs could start up in a minute or more while the CPU usage was 100%. After restarting my laptop I could log in hardly as it took minutes to see my desktop. Finally I've found this issue on Ask Ubuntu. I had to start by gnome-keyring-daemon to resolve the issue.
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Does Parallel.ForEach limit the number of active threads?
...P for any work that cannot be trivially reasoned about as being explicitly CPU bound.)
– user2864740
Apr 11 '17 at 23:31
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Find the nth occurrence of substring in a string
...actually have to copy the whole file into memory:
In [4]: %time s = mm[:]
CPU times: user 813 ms, sys: 3.25 s, total: 4.06 s
Wall time: 17.7 s
Ouch! Fortunately s still fits in the 4 GB of memory of my Macbook Air, so let's benchmark findnth():
In [5]: %timeit find_nth.findnth(s, '\n', 1000000)
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bash HISTSIZE vs. HISTFILESIZE?
... Look, my hard drive is 1 TB and largely empty, and I have gobs of idle CPU cycles and RAM, and I want to save as much bash history as reasonably possible -- so when I need to look up that stupid command I haven't run in two years, I know it's in my bash history. To make it more concrete, let's s...
Why does C++ need a separate header file?
...ough additional information to load and link the code. Then, you point the CPU at the entry point, and let it run. This is fundamentally different from Java or C#, where the code is compiled into an intermediary bytecode containing metadata on its contents.
– DevSolar
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Why should hash functions use a prime number modulus?
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@SteveJessop The number 31 is easily optimized by the CPU as a (x*32)-1 operation, in which *32 is a simple bit shift, or even better an immediate address scale factor (e.g. lea eax,eax*8; leax, eax,eax*4 on x86/x64). So *31 is a good candidate for prime number multiplication. T...