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Statistics::Basic::Covariance.3pm

NAME

Statistics::Basic::Covariance - find the covariance between two arrays

SYNOPSIS

Invoke it this way:

     my $covariance = covariance( [1,2,3], [1,2,3] );
 
 

Or this way:

     my $v1  = vector(1,2,3);
     my $v2  = vector(1,2,3);
     my $cov = cov($v1,$v2);
 
 

And then either query the values or print them like so:

     print "The covariance between $v1 and $v2: $covariance\n";
     my $cq = $cov->query;
     my $c0 = 0+$cov;
 
 

Create a 20 point ``moving'' covariance like so:

     my $sth = $dbh->prepare("select col1,col2 from data where something");
     my $len = 20;
     my $cov = cov();
        $cov->set_size($len);
 
     $sth->execute or die $dbh->errstr;
     $sth->bind_columns( my ($lhs, $rhs) ) or die $dbh->errstr;
 
     my $count = $len;
     while( $sth->fetch ) {
 
         $cov->insert( $lhs, $rhs );
         if( -- $count <= 0 ) {
             print "Covariance: $cov\n";
         }
     }
 
 

The full details are probably in the base module. If you have questions, just let me know.

AUTHOR

Paul Miller "<jettero@cpan.org>"

COPYRIGHT

Copyright 2009 Paul Miller --- Licensed under the LGPL

SEE ALSO

perl(1), Statistics::Basic