user_guide:tutorials:time

This tutorial is probably also available as a Jupyter notebook in the demo folder in the polymake source and on github.

Different versions of this tutorial: latest release, release 4.7, release 4.6, release 4.5, release 4.4, release 4.3, release 4.2, release 4.1, release 4.0, release 3.6, nightly master

# Measure execution time

The benefit of using a standard programming language such as Perl is that one can use standard libraries for basic needs. For example, one can measure the runtime/execution time of a sequence of commands. Here is an example showing how to benchmark two different convex hull algorithms/codes on the same example.

use Benchmark qw(:all);
$r=rand_sphere(3,1000,seed=>1);$t=timeit(1,'$r->FACETS;'); print timestr($t);
$r=rand_sphere(3,1000,seed=>1);$t=timeit(1,'prefer_now("beneath_beyond");$r->FACETS;'); print timestr($t);

Note that if timing a user function, you have to provide the application your function lives in:

polytope > $t=timeit(1,'Polymake::polytope::rand_box(10,2000,1);'); The above code does not work in a script file (.pl) because of polymake's modifications to Perl. You rather want to use something like this. use Benchmark qw(:all); use application 'polytope'; my$r=rand_sphere(3,100,seed=>1);

sub getfacets{
$r->FACETS; } sub myBenchmark{ my$t=Benchmark::timeit(1,"getfacets");
print timestr($t); } or that use Benchmark qw(:all); use application 'polytope'; sub myBenchmark($$) { my ($d,$n)=@_; my$r=rand_sphere($d,$n,seed=>1);

my $t0= Benchmark->new;$r->FACETS;
my $t1=Benchmark->new; my$td1=timediff($t1,$t0);
print "FACETS: ".timestr(\$td1)."\n";
}
• user_guide/tutorials/time.txt