calculating variance in perl programming

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# 1  
Old 01-12-2008
Java calculating variance in perl programming

#!/usr/bin/perl -w
use strict;

open(FH,"$ARGV[0]") or die;
my @temp=<FH>;
close FH;
my $mean = Mean(\@temp);
my $var = variance(\@temp);
print "$var\n";
sub estimate_variance {
my ($arrayref) = @_;
my ($mean,$result) = (mean($arrayref),0);
foreach (@$arrayref) { $result += ($_ - $mean)**2 }
return $result / $#{$arrayref};
error shown:
Undefined subroutine &main::variance called at line 9.

wht can be possible solution??

Last edited by cdfd123; 01-12-2008 at 10:47 AM.. Reason: correcting string
# 2  
Old 01-12-2008
variance () is not a Perl function. You will need to write your own or find a module that can do it.
# 3  
Old 01-12-2008
I though you were trying to do this in C Smilie
# 4  
Old 01-12-2008
It might be easier if you used a standard proven statistics module of which there are a number on CPAN.

For example, I have modified your code to work with the CPAN Module Statistics/Descriptive

#!/usr/local/bin/perl -w

use strict;
use Statistics::Descriptive;

open(FH, "$ARGV[0]") or die "No file specified\n";
my @temp=<FH>;
close FH;

my $stat = Statistics::Descriptive::Full->new();
my $mean = $stat->mean();
my $variance  = $stat->variance();
my $num  = $stat->count();

print "Number of Values = $num\n",
      "Mean             = $mean\n",
      "Variance         = $variance\n";

# 5  
Old 01-15-2008
Originally Posted by shamrock
I though you were trying to do this in C Smilie
Dear Shamrock
I have tried both using c and perl ..
So got results both in C and perl..
Thanks for curiosity
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