Using cov() function in PDL module

Question

I want to compute covariance using PDL, but the problem is that it always shows an error:

Undefined subroutine &main::cov called at line 12.

Can anyone tell me where I'm making a mistake?

#! usr/bin/perl

use strict;
use warnings;
use PDL;

my $a = random(5, 3);
my $b = random(5, 3);

print "$a\n$b\n";

my $cov = cov($a, $b);     #line 12

print "$cov\n";

toolic · Accepted Answer · 2012-05-09 18:31:56Z

2

That error message tells you that a function named cov is not exported by default by PDL. If I search the PDL CPAN page (using the grep tool), I do not see a function named cov.

A google search yields PDL::Stats::Basic, which has a cov function.

answered May 9, 2012 at 18:31

toolic

62.9k21 gold badges81 silver badges130 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Jordan Over a year ago

Hi, that worked. I thought that using PDL would import all the modules under it. I had to install this PDL::Stats::Basic module separately. And now it works!! Thanks!!

toolic Over a year ago

It looks like PDL::Stats is a completely separate distribution from PDL.

Ed. Over a year ago

It is completely separate. PDL doesn't import everything "under it" because that would be a vast amount of code, and take ages to load. use PDL is documented as loading a specific set of modules: metacpan.org/pod/PDL#SYNOPSIS

Collectives™ on Stack Overflow

Using cov() function in PDL module

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related