This file is indexed.

/usr/share/perl5/Statistics/Basic/LeastSquareFit.pm is in libstatistics-basic-perl 1.6611-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
package Statistics::Basic::LeastSquareFit;

use strict;
use warnings;
use Carp;

use base 'Statistics::Basic::_TwoVectorBase';

use overload
    '""' => sub {
        my ($alpha,$beta) = map{$Statistics::Basic::fmt->format_number($_, $Statistics::Basic::IPRES)} $_[0]->query;
        "LSF( alpha: $alpha, beta: $beta )";
    },
    '0+' => sub { croak "the result of LSF may not be used as a number" },
    fallback => 1; # tries to do what it would have done if this wasn't present.

# new {{{
sub new {
    my $this = shift;
    my @var1  = (shift || ());
    my @var2  = (shift || ());
    my $v1    = eval { Statistics::Basic::Vector->new( @var1 ) } or croak $@;
    my $v2    = eval { Statistics::Basic::Vector->new( @var2 ) } or croak $@;

    $this = bless {}, $this;

    my $c = $v1->_get_linked_computer( LSF => $v2 );
    return $c if $c;

    $this->{_vectors} = [ $v1, $v2 ];

    $this->{vrx} = eval { Statistics::Basic::Variance->new($v1)        } or croak $@;
    $this->{mnx} = eval { Statistics::Basic::Mean->new($v1)            } or croak $@;
    $this->{mny} = eval { Statistics::Basic::Mean->new($v2)            } or croak $@;
    $this->{cov} = eval { Statistics::Basic::Covariance->new($v1, $v2) } or croak $@;

    $v1->_set_linked_computer( LSF => $this, $v2 );
    $v2->_set_linked_computer( LSF => $this, $v1 );

    return $this;
}
# }}}
# _recalc {{{
sub _recalc {
    my $this  = shift;

    delete $this->{recalc_needed};
    delete $this->{alpha};
    delete $this->{beta};

    my $vrx = $this->{vrx}->query; return unless defined $vrx; return unless $vrx > 0;
    my $mnx = $this->{mnx}->query; return unless defined $mnx;
    my $mny = $this->{mny}->query; return unless defined $mny;
    my $cov = $this->{cov}->query; return unless defined $cov;

    $this->{beta}  = ($cov / $vrx);
    $this->{alpha} = ($mny - ($this->{beta} * $mnx));

    warn "[recalc " . ref($this) . "] (alpha: $this->{alpha}, beta: $this->{beta})\n" if $Statistics::Basic::DEBUG;

    return;
}
# }}}
# query {{{
sub query {
    my $this = shift;

    $this->_recalc if $this->{recalc_needed};

    warn "[query " . ref($this) . " ($this->{alpha}, $this->{beta})]\n" if $Statistics::Basic::DEBUG;

    return (wantarray ? ($this->{alpha}, $this->{beta}) : [$this->{alpha}, $this->{beta}] );
}
# }}}

# query_vector1 {{{
sub query_vector1 {
    my $this = shift;

    return $this->{cov}->query_vector1;
}
# }}}
# query_vector2 {{{
sub query_vector2 {
    my $this = shift;

    return $this->{cov}->query_vector2;
}
# }}}
# query_mean1 {{{
sub query_mean1 {
    my $this = shift;

    return $this->{mnx};
}
# }}}
# query_variance1 {{{
sub query_variance1 {
    my $this = shift;

    return $this->{vrx};
}
# }}}
# query_covariance {{{
sub query_covariance {
    my $this = shift;

    return $this->{cov};
}
# }}}

# y_given_x {{{
sub y_given_x {
    my $this = shift;
    my ($alpha, $beta) = $this->query;
    my $x = shift;

    return ($beta*$x + $alpha);
}
# }}}
# x_given_y {{{
sub x_given_y {
    my $this = shift;
    my ($alpha, $beta) = $this->query;
    my $y = shift;

    defined( my $x = eval { ( ($y-$alpha)/$beta ) }) or croak $@;
    return $x;
}
# }}}

1;