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Re: Writing efficient normal distribution function (for learning purposes).

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lucacerone <luca.cerone@gmail.com> writes:
> As for the compiler optimization, I'm using g++ (GNU compiler) on a
> Ubuntu machine. The way I compile the code is simply:
>
> g++ -c -o mylib.o mylib.cpp
> g++ -c -o main.o main.cpp
> g++ -o executableneme main.o mylib.o
>
> I have absolutely no idea on how to optimize compilation...

As a start, you should turn on optimization -- the compiler does no
optimization unless you tell it to, and in many cases non-optimized code
is much, _much_ slower.

To turn on optimization, use the "-O" option, optionally followed by a
digit giving the level of optimization; with gcc, the most common choice
is "-O2" which optimizes somewhat more.

You also want to tell it what processor you're using, because by default
it will produce "generic" code that can run on almost any processor in
the same family, but can be significantly slower than code which is
precisely targetted at the processor you're using.  To do this, use the
"-march=..." option; typically you can use "-march=native", which says
"produce code targetted at the processor in this machine."

So i'd suggest:

  g++ -c -o mylib.o -O2 -march=native mylib.cpp
  g++ -c -o main.o -O2 -march=native  main.cpp
  g++ -o executableneme main.o mylib.o

-Miles

-- 
Infancy, n. The period of our lives when, according to Wordsworth, 'Heaven
lies about us.' The world begins lying about us pretty soon afterward.

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Writing efficient normal distribution function (for learning purposes). Luca Cerone <luca.cerone@gmail.com> - 2012-02-17 07:41 -0800
  Re: Writing efficient normal distribution function (for learning purposes). "Asger Joergensen" <Junk@Asger-P.dk> - 2012-02-17 16:45 +0000
    Re: Writing efficient normal distribution function (for learning purposes). lucacerone <luca.cerone@gmail.com> - 2012-02-17 09:36 -0800
      Re: Writing efficient normal distribution function (for learning purposes). "Asger Joergensen" <Junk@Asger-P.dk> - 2012-02-17 17:50 +0000
        Re: Writing efficient normal distribution function (for learning purposes). lucacerone <luca.cerone@gmail.com> - 2012-02-19 01:59 -0800
          Re: Writing efficient normal distribution function (for learning purposes). lucacerone <luca.cerone@gmail.com> - 2012-02-19 02:49 -0800
            Re: Writing efficient normal distribution function (for learning purposes). "Asger Joergensen" <Junk@Asger-P.dk> - 2012-02-19 11:53 +0000
            Re: Writing efficient normal distribution function (for learning purposes). Miles Bader <miles@gnu.org> - 2012-02-19 23:09 +0900
              Re: Writing efficient normal distribution function (for learning purposes). Joshua Maurice <joshuamaurice@gmail.com> - 2012-02-19 13:34 -0800
                Re: Writing efficient normal distribution function (for learning purposes). Marc <marc.glisse@gmail.com> - 2012-02-19 22:10 +0000
                Re: Writing efficient normal distribution function (for learning purposes). Miles Bader <miles@gnu.org> - 2012-02-20 09:14 +0900
                Re: Writing efficient normal distribution function (for learning purposes). Juha Nieminen <nospam@thanks.invalid> - 2012-02-20 10:24 +0000
                Re: Writing efficient normal distribution function (for learning purposes). Miles Bader <miles@gnu.org> - 2012-02-20 19:57 +0900
                Re: Writing efficient normal distribution function (for learning purposes). Dombo <dombo@disposable.invalid> - 2012-02-20 21:07 +0100
                Re: Writing efficient normal distribution function (for learning purposes). Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 08:41 +0000
                Re: Writing efficient normal distribution function (for learning purposes). 88888 Dihedral <dihedral88888@googlemail.com> - 2012-02-21 01:10 -0800
                Re: Writing efficient normal distribution function (for learning purposes). Miles Bader <miles@gnu.org> - 2012-02-20 09:04 +0900
              Re: Writing efficient normal distribution function (for learning purposes). lucacerone <luca.cerone@gmail.com> - 2012-02-20 02:26 -0800
    Re: Writing efficient normal distribution function (for learning purposes). Juha Nieminen <nospam@thanks.invalid> - 2012-02-17 20:42 +0000
      Re: Writing efficient normal distribution function (for learning purposes). "Asger Joergensen" <Junk@Asger-P.dk> - 2012-02-17 22:20 +0000
  Re: Writing efficient normal distribution function (for learning purposes). Juha Nieminen <nospam@thanks.invalid> - 2012-02-17 20:52 +0000
  Re: Writing efficient normal distribution function (for learning purposes). Victor Bazarov <v.bazarov@comcast.invalid> - 2012-02-17 15:57 -0500
  Re: Writing efficient normal distribution function (for learning purposes). Joshua Maurice <joshuamaurice@gmail.com> - 2012-02-17 15:01 -0800
    Re: Writing efficient normal distribution function (for learning purposes). Victor Bazarov <v.bazarov@comcast.invalid> - 2012-02-18 08:44 -0500
      Re: Writing efficient normal distribution function (for learning purposes). Paavo Helde <myfirstname@osa.pri.ee> - 2012-02-18 09:20 -0600
  Re: Writing efficient normal distribution function (for learning purposes). Paavo Helde <myfirstname@osa.pri.ee> - 2012-02-18 09:36 -0600
    Re: Writing efficient normal distribution function (for learning purposes). glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-02-18 20:19 +0000
      Re: Writing efficient normal distribution function (for learning purposes). Miles Bader <miles@gnu.org> - 2012-02-19 10:32 +0900
  Re: Writing efficient normal distribution function (for learning purposes). lucacerone <luca.cerone@gmail.com> - 2012-02-20 02:36 -0800
  Re: Writing efficient normal distribution function (for learning purposes). gwowen <gwowen@gmail.com> - 2012-02-20 06:48 -0800
    Re: Writing efficient normal distribution function (for learning purposes). lucacerone <luca.cerone@gmail.com> - 2012-02-21 04:32 -0800

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