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How to find out which package version is loaded in R?
... LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] graphics grDevices utils datasets stats grid methods base
other attached packages:
[1] ggplot2_0.9.0 reshape2_1.2.1 plyr_1.7.1
loaded via a namespace (and not attached):
[1] co...
How do I analyze a program's core dump file with GDB when it has command-line parameters?
...2'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x0000564583cf2759 in myfunc (i=3) at main.c:7
7 *(int*)(NULL) = i; /* line 7 */
(gdb) bt
#0 0x0000564583cf2759 in myfunc (i=3) at main.c:7
#1 0x0000564583cf2858 in main (argc=3, argv=0x7ffcca4effa8) at main.c:2
So not...
Do try/catch blocks hurt performance when exceptions are not thrown?
...r version), but it was no difference in the Release version.
Conclution:
Based on these test, I think we can say that Try/Catch does have a small impact on performance.
EDIT:
I tried to increase the loop value from 10000000 to 1000000000, and ran again in Release to get some differences in the re...
How to run a program without an operating system?
...n:
an x86 Lenovo Thinkpad T430 laptop with UEFI BIOS 1.16 firmware
an ARM-based Raspberry Pi 3
We will also try them out on the QEMU emulator as much as possible, as that is safer and more convenient for development. The QEMU tests have been on an Ubuntu 18.04 host with the pre-packaged QEMU 2.11....
Best practices for circular shift (rotate) operations in C++
...motion rules mean that rotl_template(u16 & 0x11UL, 7) would do a 32 or 64-bit rotate, not 16 (depending on the width of unsigned long). Even uint16_t & uint16_t is promoted to signed int by C++'s integer-promotion rules, except on platforms where int is no wider than uint16_t.
On x86, th...
Python dictionary: Get list of values for list of keys
...
A little speed comparison:
Python 2.7.11 |Anaconda 2.4.1 (64-bit)| (default, Dec 7 2015, 14:10:42) [MSC v.1500 64 bit (AMD64)] on win32
In[1]: l = [0,1,2,3,2,3,1,2,0]
In[2]: m = {0:10, 1:11, 2:12, 3:13}
In[3]: %timeit [m[_] for _ in l] # list comprehension
1000000 loops, best of 3...
Convert timestamp to date in MySQL query
... format use date_format
date_format(registration, '%Y-%m-%d')
SQLFiddle demo
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How to play audio?
...t
soundManager.play('mySound');
});
</script>
Here's a demo of it in action: http://www.schillmania.com/projects/soundmanager2/demo/christmas-lights/
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Linux C++ 单元测试与gcov代码覆盖率统计 - C/C++ - 清泛网 - 专注C/C++及内核技术
...--rc lcov_branch_coverage=1 -r xxx.tmp '/usr/include/*' '*lib/*' -o xxx
Demo shell:
g++ --coverage demo.cpp # demo.gcno
./a.out # demo.gcda
gcov demo # demo.cpp.gcov
cat demo.cpp.gcov
lcov --rc lcov_branch_coverage=1 -c -d . -o demo_lcov_report
#all
#genhtml --rc genhtml_branch_cover...
What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?
...lt; N), finding the position (N) of the highest set bit is the integer log base 2 of that integer.
http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
unsigned int v;
unsigned r = 0;
while (v >>= 1) {
r++;
}
This "obvious" algorithm may not be transparent to everyone...