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--- tutorial:perl_continued [2011/05/20 12:05] – herr
+++ tutorial:perl_continued [2017/07/26 14:44] (current) – fused with perl_intro oroehrig
@@ Line 1: / Line 1: @@
-====Using Perl within polymake====
-This is a tutorial about how to use Perl within ''polymake'', which was presented at the [[:workshop0311|polymake-Workshop]] at Darmstadt, in March 2011. A short introduction to Perl in ''polymake'' can be found at "[[tutorial:perl_intro|polymake for the Perl Newbie]]".
-===Standard data structures===
-The Perl programming language originally provides three different data structures, scalars($), arrays(@), and hashes(%). The user always has to specify the type of a variable using the appropriate symbol ''$'', ''@'', or ''%''. If you forget to do so, you will receive the following error message:
-<code>
-polytope > i=5;
-polymake:  ERROR: Unquoted string "i" may clash with future reserved word.
-</code>\\
-Here are some simple commands illustrating how to use the different data structures:
-  * **Scalars** <code>
-$i=5;
-$j=6;
-$sum=$i+$j; print $sum;
-</code>
-  * **Arrays** <code>
-@array=("a","b","c"); print scalar(@array);
-push(@array,"d"); print "@array";
-$first_entry=$array[0]; print $first_entry;
-print join("\n",@array);
-@array2=(3,1,4,2);
-print sort(@array2);
-</code>
-  * **Hashes** <code>
-%hash=();
-$hash{"zero"}=0;
-$hash{"four"}=4;
-print keys %hash;
-print join(", ",keys %hash);
-print join(", ",values %hash);
-%hash=("one",1,"two",2);
-%hash=("one"=>1,"two"=>2);
-</code>\\
-==="Small objects": Data structures inherited from C++===
-In addition to the three standard data structures, the enriched version of ''Perl'' used in ''polymake'' also provides special data structures that are inherited from the ''C++''-side of ''polymake''.
-<code>
-$arr1=new Array<String>(\@array); print $arr1;
-$arr2=new Array<Int>([3,2,5]); print $arr2;
-$arr3=new Array<Int>(0,1,2,3); print $arr3;
-$arr4=new Array<Int>(0..4); print $arr4;
-@arr4=@{$arr4};
-print $arr2;
-$set=new Set<Int>(3,2,5); print $set;
-$mat=new Matrix<Rational>([[2,1,4,0,0],[3,1,5,2,1],[1,0,4,0,6]]); print $mat;
-$mat->row(1)->[1]=7; print $mat;
-$mat->(1,2)=8; print $mat;
-print 4*unit_matrix<Rational>(3);
-$m_rat=new Matrix<Rational>(3/5*unit_matrix<Rational>(5)); print $m_rat;
-$m2=$mat/$m_rat; print $m2;
-$m_int=new Matrix<Int>(unit_matrix<Rational>(5)); print $m_int;
-$m3=$m_rat/$m_int;
-$m3=$m_rat/(convert_to<Rational>($m_int)); print $m3;
-$z_vec=zero_vector<Int>($m_int->rows);
-$extended_matrix=($z_vec|$m_int); print $extended_matrix;
-$template_Ex=new Array<Set<Int>>((new Set<Int>(5,2,6)),$set); print
-$template_Ex;
-</code>
-==="Big Objects": Objects with properties===
-<code>
-$p=new Polytope<Rational>(POINTS=>cube(4)->VERTICES);
-$lp=new LinearProgram<Rational>(LINEAR_OBJECTIVE=>[0,1,1,1,1]);
-$p->LP=$lp;
-print $p->LP->MAXIMAL_VALUE;
-</code>
-===Working with Perl in polymake===
-{{:points.demo|}}
-<code>
-open(INPUT, "< /home/katrin/polymake/demo/Workshop2011/points.demo");
-$matrix=new Matrix<Rational>(<INPUT>);
-close(INPUT);
-print $matrix;
-$p=new Polytope<Rational>(POINTS=>$matrix);
-print $p->FACETS;
-print $p->DIM;
-print $p->VERTEX_SIZES;
-;### choose "simple" vertices
-for(my $i=0;$i<scalar(@{$p->VERTEX_SIZES});$i++){
-    if($p->VERTEX_SIZES->[$i]==$p->DIM){
-	print $i.": ".$p->VERTICES->row($i)."\n";
-    }
-}
-$s=new Set<Int>();
-for(my $i=0;$i<scalar(@{$p->VERTEX_SIZES});$i++){
-    if($p->VERTEX_SIZES->[$i]==$p->DIM){
-	$s+=$i;
-    }
-}
-$special_points=$p->VERTICES->minor($s,All); print $special_points;
-;
-foreach(@{$s}){
-    print $p->VERTICES->row($_)."\n";
-}
-foreach my $index(@{$s}){
-    print $p->VERTICES->row($index)."\n";
-}
-</code>
-===Scripts===
-[[scripting:start|Scripting]]