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lib/Math/Zap/Matrix2.pm  view on Meta::CPAN

Identity matrix

=cut


sub identity()
 {bless
   {11=>1, 21=>0,                              
    12=>0, 22=>1,                              
   }; 
 }


=head3 new2v

Create a matrix from two vectors

=cut


sub new2v($$)
 {vector2Check(@_) if debug;
  my ($a, $b, $c) =  @_;
  my $m = round(bless(
   {11=>$a->{x}, 12=>$b->{x},
    21=>$a->{y}, 22=>$b->{y},
   }));
  singular($m, 1);
  $m;
 }


=head2 Methods


=head3 check

Check its a matrix

=cut


sub check(@)
 {if (debug)
   {for my $m(@_)
     {confess "$m is not a matrix2" unless ref($m) eq __PACKAGE__;
     } 
   }
  return (@_)
 }


=head3 is

Test its a matrix

=cut


sub is(@)
 {for my $m(@_)
   {return 0 unless ref($m) eq __PACKAGE__;
   }
  'matrix2';
 }


=head3 accuracy

Get/Set accuracy 

=cut


my $accuracy = 1e-10;

sub accuracy
 {return $accuracy unless scalar(@_);
  $accuracy = shift();
 }


=head3 round

Round: round to nearest integer if within accuracy of that integer 

=cut


sub round($)
 {unless (debug)
   {return $_[0];
   }
  else
   {my ($a) = @_;
    for my $k(keys(%$a))
     {my $n = $a->{$k};
      my $N = int($n);
      $a->{$k} = $N if abs($n-$N) < $accuracy;
     }
    return $a;
   }
 }


=head3 singular

Singular matrix?

=cut


sub singular($$)
 {my $m = shift;  # Matrix   
  my $a = 1e-2;   # Accuracy
  my $A = shift;  # Action 0: return indicator, 1: confess 
  my $n = abs
    ($m->{11} * $m->{22} -                                        
     $m->{12} * $m->{21})
    < $a;