forum.polymake.org

Posted: **01 Jun 2016, 15:43**

Hello everyone,
I have a file with a list of polytopes given by their vertices. I try do some simple calculations on them, but it does not work yet. I wrote a comment to note, where the error occurs. I cannot read the vertices, instead I get the error message:

}
polymake: WARNING: could not compute 'VERTICES' probably because of unsatisfied preconditions:
precondition : RAYS | INPUT_RAYS | LINEALITY_SPACE | INPUT_LINEALITY | INEQUALITIES | FACETS | EQUATIONS | LINEAR_SPAN ( CONE_AMBIENT_DIM : )
precondition : INPUT_RAYS | RAYS ( FACETS, LINEAR_SPAN : )

Can anybody help me find my mistake? I also added the file that gets read.

Code: Select all

 open( INPUT, "< neighb.txt" ) or die "Can't open $filename: $!";
    while (my $line = <INPUT> ) {
	chomp $line;
	$line=substr $line, 6, -2; #removes the unneccessary stuff and prepares parsing
	$line="\[\[1,".join ("\], \[1, ",split(/\], \[/, $line))."\]\]"; #parses the vertices and adds a 1 for the homogenous coordinate
	my $points;
	eval('$points=new Matrix<Rational>('.$line.');'); #creates matrix with the coordinates in it
	my $p=new Polytope<Rational>(POINTS=>$points); 
	print $p->VERTICES; #here is where I get the error message
	#$p=polarize(center($p))->TWO_FACE_SIZES; #this does not work as well, when I delete the line above
	#my $s=0;foreach(1..20){
	#	$s+=$p->{$_} if $_!=4;
	#};
	#print $s/9;
	print "\n";
	
    }
    close(INPUT);

Code: Select all

0:  [[-123984206864/2768850730773, -101701330976/922950243591, -64154618668/2768850730773, -2748446474675/2768850730773], [-11083969050/98314591817, -4717557075/98314591817, -32618537490/98314591817, -91960210208/98314591817], [-9690950/554883199, -73651220/554883199, 1823050/554883199, -549885101/554883199], [-5174928/72012097, 5436288/72012097, -37977984/72012097, 60721345/72012097], [-19184/902877, 26136/300959, -21472/902877, 899005/902877], [53511524/1167061933, 88410344/1167061933, 621795064/1167061933, 982203941/1167061933], [4674489456/83665171433, -4026061312/83665171433, 28596876672/83665171433, -78383796375/83665171433], [857794884940/98972360190089, -10910202223200/98972360190089, 2974263671400/98972360190089, -98320463346111/98972360190089]]
1:  [[-1002945720/30187053481, -3059834400/30187053481, -1228096800/30187053481, -29989689719/30187053481], [-39421800/3581181049, -432445200/3581181049, -64866780/3581181049, -3554164751/3581181049], [-3447600/44369069, 3381300/44369069, -27350960/44369069, 34600869/44369069], [-611618/7662509, -379358/7662509, -2140663/7662509, -7322132/7662509], [-1050/84439, 8550/84439, -1260/84439, 83989/84439], [10890/189967, 15246/189967, 114048/189967, 150763/189967], [3042000/61794121, -3120000/61794121, 14601600/61794121, -59885879/61794121], [173660563125/15757451586458, -1598265860625/15757451586458, 59871546525/15757451586458, -15675110339167/15757451586458]]
2:  [[-430629/14864582, -376119/14864582, -376119/14864582, -14848819/14864582], [-381312/570703313, -47330352/570703313, 63107136/570703313, -565225135/570703313], [-90/5843, 300/5843, -1575/5843, 5618/5843], [-24/281, 48/281, -180/281, 209/281], [18/157, 18/157, 135/157, 76/157], [6768/320341, -159048/1601705, 212064/1601705, -315851/320341], [54144/1284005, -106032/1284005, 212064/1284005, -1260763/1284005], [7489200/93635641, -2275200/93635641, 35948160/93635641, -86105159/93635641]]

Posted: **01 Jun 2016, 17:23**

The input parsing can be simplified, since the input lines are already in valid perl/polymake-compliant format. You just have to append a column with homogeneous 1's:

Code: Select all

$line =~ s/^\d+://;  # remove the line number
my $points=new Matrix<Rational>(eval $line);
my $p=new Polytope<Rational>(POINTS => (ones_vector<Rational>()) | $points);   # make homogeneous coordinates
print "POINTS:\n", $p->POINTS;   # verify the correctness of input parsing
print "VERTICES:\n", $p->VERTICES;

BTW, your mistake is superfluous backslashes in front of square brackets in strings (as opposed to regular expressions).

Posted: **15 Jun 2016, 14:15**

Thank you very much for your quick help.
Unfortunately, it still cannot compute the vertices and the centering does not work. I do not get any error message for the output, but a warning and no vertices or points behind the "POINTS:".
Also, I receive the following for the centering part:

polymake: WARNING: available properties insufficient to compute 'POINTS'
POINTS:
polymake: WARNING: rule REL_INT_POINT : CONE_AMBIENT_DIM failed: unit_vector - invalid dimension or index out of range at input line 7.
polymake: WARNING: rule REL_INT_POINT : VERTEX_BARYCENTER failed: attempt to use a property VERTEX_BARYCENTER with undefined value
polymake: WARNING: rule REL_INT_POINT : VERTICES | POINTS failed: computed point not affine at /import/polymake-2.14/share/polymake/apps/polytope/rules/polarize.rules line 51.
polymake: WARNING: rule TRIANGULATION.FACETS : RAYS ( applied to parent ) failed: std::bad_alloc at /import/polymake-2.14/share/polymake/apps/polytope/rules/cone_common.rules line 514.
polymake: WARNING: rule default.volume: CENTROID, VOLUME : VERTICES, TRIANGULATION failed: no more rules available to compute 'FACETS'
polymake: WARNING: rule CONE_DIM, REL_INT_POINT : FACETS | INEQUALITIES, ONE_VERTEX, BOUNDED failed: unexpected undefined value of an input property at /import/polymake-2.14/share/polymake/apps/polytope/rules/polarize.rules line 59.

polymake: ERROR: no more rules available to compute 'REL_INT_POINT'

Code: Select all

 open( INPUT, "< neighb.txt" ) or die "Can't open $filename: $!";
    while (my $line = <INPUT> ) {

	$line =~ s/^\d+://;  # remove the line number
my $points=new Matrix<Rational>(eval $line);
my $p=new Polytope<Rational>(POINTS => (ones_vector<Rational>()) | $points);   # make homogeneous coordinates
print "POINTS:\n", $p->POINTS;   # verify the correctness of input parsing
print "VERTICES:\n", $p->VERTICES;
	$p=polarize(center($p))->TWO_FACE_SIZES;
	#my $s=0;foreach(1..20){
	#	$s+=$p->{$_} if $_!=4;
	#}
	#print $s/9;


	
    }
    close(INPUT);

Posted: **15 Jun 2016, 18:33**

Well, something still goes wrong in the input parsing part, the points matrix is then obviously empty and nothing interesting can be computed from it. Could you add some debugging output:

Code: Select all

...
   $line =~ s/^\d+://; 
   my $parsed=eval $line;
   if ($@) {
      print STDERR "ERROR parsing line '$line': $@\n"; last;
   }
   print STDERR "parsed '$line' as $parsed\n";
   my $points=new Matrix<Rational>($parsed);
   print STDERR "points: ", $points->rows, " x ", $points->cols, "\n";

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Creating polytope - unsatisfied preconditions

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