http://www.perlmonks.org?node_id=1197296


in reply to High Performance Game of Life

Hi eyepopslikeamosquito,

Unfortunately, method calling in Perl is expensive. The following change to Organism.pm will run two times faster simply by inlining is_alive.

Before:

sub is_alive { my $self = shift; return 0 + exists $self->{Cells}->{ join ':', @_ }; } # Return the list of dead cells surrounding a cell sub get_dead_cells { my ( $self, $x, $y ) = @_; ( (join ':', $x - 1, $y - 1) x !$self->is_alive($x - 1, $y - 1), (join ':', $x - 1, $y ) x !$self->is_alive($x - 1, $y ), (join ':', $x - 1, $y + 1) x !$self->is_alive($x - 1, $y + 1), (join ':', $x , $y - 1) x !$self->is_alive($x , $y - 1), (join ':', $x , $y + 1) x !$self->is_alive($x , $y + 1), (join ':', $x + 1, $y - 1) x !$self->is_alive($x + 1, $y - 1), (join ':', $x + 1, $y ) x !$self->is_alive($x + 1, $y ), (join ':', $x + 1, $y + 1) x !$self->is_alive($x + 1, $y + 1) ); } sub get_num_live { my ( $self, $x, $y ) = @_; $self->is_alive( $x - 1, $y - 1 ) + $self->is_alive( $x - 1, $y ) + $self->is_alive( $x - 1, $y + 1 ) + $self->is_alive( $x , $y - 1 ) + $self->is_alive( $x , $y + 1 ) + $self->is_alive( $x + 1, $y - 1 ) + $self->is_alive( $x + 1, $y ) + $self->is_alive( $x + 1, $y + 1 ); }

After:

# Return the list of dead cells surrounding a cell sub get_dead_cells { my ( $cells, $x0, $y0 ) = ( shift->{Cells}, @_ ); my ( $x1, $x2, $y1, $y2 ) = ( $x0 - 1, $x0 + 1, $y0 - 1, $y0 + 1 ); ( ( "$x1:$y1" ) x !( 0 + exists $cells->{ "$x1:$y1" } ), ( "$x1:$y0" ) x !( 0 + exists $cells->{ "$x1:$y0" } ), ( "$x1:$y2" ) x !( 0 + exists $cells->{ "$x1:$y2" } ), ( "$x0:$y1" ) x !( 0 + exists $cells->{ "$x0:$y1" } ), ( "$x0:$y2" ) x !( 0 + exists $cells->{ "$x0:$y2" } ), ( "$x2:$y1" ) x !( 0 + exists $cells->{ "$x2:$y1" } ), ( "$x2:$y0" ) x !( 0 + exists $cells->{ "$x2:$y0" } ), ( "$x2:$y2" ) x !( 0 + exists $cells->{ "$x2:$y2" } ) ); } sub get_num_live { my ( $cells, $x0, $y0 ) = ( shift->{Cells}, @_ ); my ( $x1, $x2, $y1, $y2 ) = ( $x0 - 1, $x0 + 1, $y0 - 1, $y0 + 1 ); ( 0 + exists $cells->{ "$x1:$y1" } ) + ( 0 + exists $cells->{ "$x1:$y0" } ) + ( 0 + exists $cells->{ "$x1:$y2" } ) + ( 0 + exists $cells->{ "$x0:$y1" } ) + ( 0 + exists $cells->{ "$x0:$y2" } ) + ( 0 + exists $cells->{ "$x2:$y1" } ) + ( 0 + exists $cells->{ "$x2:$y0" } ) + ( 0 + exists $cells->{ "$x2:$y2" } ); }

Regards, Mario