I installed OpenCV to MAC OSX by using homebrew one month ago, then I had a worrisome thing which I found many people also had, so I like to share my case because this depends
on people's environment.
There are a lot of web pages about how to install OpenCV by homebrew to MAC OSX, so I omit it here.
During the installation, it looks like stuck at
==> make bootstrap
in the middle. And the name of a tab in terminal changes sometimes rapidly but stops sometimes. What is concern is that it does not finish and looks stuck. As far as I found in web search, this takes long time actually. It took about one hour in my case to be finished.
MAC spec is
OSX Version 10.9.5
2.5 GHz Intel Core i5
4 GB 1600 MHz DDR3
I hope this helps somebody.
It's been more than one year since I posted last time. Actually, I was busy with my job.
I'm not a programmer, but I often write a script to extract specific data from numerical simulation results and to make some input sequence files for simulation. When it comes to this type of work, Perl seems to be better than others according to web evaluation.
One day, I heard news that the longest prime number was found by the computer, and I became wondering how long does it take to find prime numbers by a Perl script.
Here is a script to find numerical numbers up to N.
# script to find prime numbers to N
$N=100000;
# 2 is an exceptional number to this script
print "2\n";
$numP=1;
# start to find prime numbers from 3
for($k=3;$k<=$N;$k+=2){
$m=2;
until($k%$m==0){
$m++;
}
if($k==$m){
print "$k\n";
$numP++;
}
}
print "\n";
print "the number of prime number to $N is $numP\n";
In this script, I take the number 2 as an exceptional one, and try to find prime numbers from 3 in for-loop. For each $k over 3, modulo is performed from 2 to $k until 0 is found. if $k is dividable by itself, then it is a prime number. To save time, even numbers are skipped.
I compared the process time of three computers by using build-in function "time" in Linux.
time perl scriptname.pl
As is set above script, I run the script to find numbers up to 100,000. Here are comparison results.
8 minutes -- Raspberry Pi 2 model B
36 seconds -- Mac book pro 2012
17 seconds -- Company Linux machine
This makes sense to me in terms of computer spec. Company machine is as powerful as being able to run the advanced spice simulator easily and memory is also over 100G.
When $N increases, then the process time also increases exponentially. Try it.
I'm now thinking to write a script to calculate pi next.
