1Statistics::Basic::CovaUrsiearncCeo(n3t)ributed Perl DocSutmaetnitsattiicosn::Basic::Covariance(3)
2
3
4

NAME

6       Statistics::Basic::Covariance - find the covariance between two lists
7

SYNOPSIS

9       Invoke it this way:
10
11           my $covariance = covariance( [1,2,3], [1,2,3] );
12
13       Or this way:
14
15           my $v1  = vector(1,2,3);
16           my $v2  = vector(1,2,3);
17           my $cov = cov($v1,$v2);
18
19       And then either query the values or print them like so:
20
21           print "The covariance between $v1 and $v2: $covariance\n";
22           my $cq = $cov->query;
23           my $c0 = 0+$cov;
24
25       Create a 20 point "moving" covariance like so:
26
27           use Statistics::Basic qw(:all nofill);
28
29           my $sth = $dbh->prepare("select col1,col2 from data where something");
30           my $len = 20;
31           my $cov = cov();
32              $cov->set_size($len);
33
34           $sth->execute or die $dbh->errstr;
35           $sth->bind_columns( my ($lhs, $rhs) ) or die $dbh->errstr;
36
37           my $count = $len;
38           while( $sth->fetch ) {
39               $cov->insert( $lhs, $rhs );
40               if( defined( my $c = $cov->query ) ) {
41                   print "Covariance: $c\n";
42               }
43
44               # This would also work:
45               # print "Covariance: $cov\n" if $cov->query_filled;
46           }
47

METHODS

49       This list of methods skips the methods inherited from
50       Statistics::Basic::_TwoVectorBase (things like query(), insert(), and
51       ginsert()).
52
53       new()
54           Create a new Statistics::Basic::Covariance object.  This function
55           takes two arguments -- which can either be arrayrefs or
56           Statistics::Basic::Vector objects.  This function is called when
57           the covariance() shortcut-function is called.
58
59       query_vector1()
60           Return the Statistics::Basic::Vector for the first vector.
61
62       query_vector2()
63           Return the Statistics::Basic::Vector object for the second vector.
64
65       query_mean1()
66           Returns the Statistics::Basic::Mean object for the first vector.
67
68       query_mean2()
69           Returns the Statistics::Basic::Mean object for the second vector.
70

OVERLOADS

72       This object is overloaded.  It tries to return an appropriate string
73       for the calculation or the value of the computation in numeric context.
74
75       In boolean context, this object is always true (even when empty).
76

AUTHOR

78       Paul Miller "<jettero@cpan.org>"
79

81       Copyright 2012 Paul Miller -- Licensed under the LGPL
82

SEE ALSO

84       perl(1), Statistics::Basic, Statistics::Basic::_TwoVectorBase,
85       Statistics::Basic::Vector
86
87
88
89perl v5.30.1                      2020-01-30  Statistics::Basic::Covariance(3)
Impressum