[task #16114] Print warning where integer overflow happens

[Mohammad Akhlaghi]

Follow-up Comment #16, task #16114 (project gnuastro):

Thanks a lot for the nice work Siyang! I reviewed the commits and made some
additional changes in the
[https://gitlab.com/makhlaghi/gnuastro-dev/-/tree/overflowcheck overflowcheck]
branch of my development fork. Have a look at the commits messages and changes
(the good news is that the compile time is now almost identical to the
'master' branch).

To get a good statistical feeling of the effect of the overflow checks on the
run-time, I wrote the following script after installing the Gnuastro of this
branch (note that the script has to be run as root to allow cleaning the RAM).
I chose 64-bit integer to best show the difference:


type=int64

astarithmetic 10000 10000 2 makenew 100 u8 + \
              20 mknoise-sigma $type -onoised-1.fits
astarithmetic 10000 10000 2 makenew 100 u8 + \
              20 mknoise-sigma $type -onoised-2.fits

for i in $(seq 25); do
    echo test $i
    sync; echo 3 > /proc/sys/vm/drop_caches
    { time astarithmetic noised-1.fits noised-2.fits x -ojunk.fits -g1 -q; }
\
        2> junk.txt
    awk '/^real/{print $2}' junk.txt | sed -e's|0m||' -e's|s||' >> $type.txt
done


Here is the result as two histograms:

(file #54813)

In short: the overflow checks almost double the run-time :-(. Can you have a
look to see if you can reproduce this difference? Did I do a bad change
somewhere in my commits?


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