VecStat(3pm) User Contributed Perl Documentation VecStat(3pm)
NAME
Math::VecStat - Some basic numeric stats on vectors
SYNOPSIS
use Math::VecStat qw(max min maxabs minabs sum average);
$max=max(@vector);
$max=max(@vector);
($max,$imax)=max(@vector);
($max,$imax)=max(@vector);
$min=min(@vector);
$min=min(@vector);
($max,$imin)=min(@vector);
($max,$imin)=min(@vector);
$max=maxabs(@vector);
$max=maxabs(@vector);
($max,$imax)=maxabs(@vector);
($max,$imax)=maxabs(@vector);
$min=minabs(@vector);
$min=minabs(@vector);
($max,$imin)=minabs(@vector);
($max,$imin)=minabs(@vector);
$sum=sum($v1,$v2,...);
$sum=sum(@vector);
$sum=sum(@vector);
$average=average($v1,$v2,...);
$av=average(@vector);
$av=average(@vector);
$ref=vecprod($scalar,@vector);
$ok=ordered(@vector);
$ok=ordered(@vector);
$ref=sumbyelement(@vector1,@vector2);
$ref=diffbyelement(@vector1,@vector2);
$ok=allequal(@vector1,@vector2);
$ref=convolute(@vector1,@vector2);
DESCRIPTION
This package provides some basic statistics on numerical vectors. All the subroutines can take a reference to the vector to be operated on.
In some cases a copy of the vector is acceptable, but is not recommended for efficiency.
max(@vector), max(@vector)
return the maximum value of given values or vector. In an array context returns the value and the index in the array where it occurs.
min(@vector), min(@vector)
return the minimum value of given values or vector, In an array context returns the value and the index in the array where it occurs.
maxabs(@vector), maxabs(@vector)
return the maximum value of absolute of the given values or vector. In an array context returns the value and the index in the array
where it occurs.
minabs(@vector), minabs(@vector)
return the minimum value of the absolute of the given values or vector. In an array context returns the value and the index in the
array where it occurs.
sum($v1,$v2,...), sum(@vector), sum(@vector)
return the sum of the given values or vector
average($v1,$v2,..), average(@vector), average(@vector)
return the average of the given values or vector
vecprod($a,$v1,$v2,..), vecprod($a,@vector), vecprod( $a, @vector )
return a vector built by multiplying the scalar $a by each element of the @vector.
ordered($v1,$v2,..), ordered(@vector), ordered(@vector)
return nonzero iff the vector is nondecreasing with respect to its index. To be used like
if( ordered( $lowBound, $value, $highBound ) ){
instead of the (slightly) more clumsy
if( ($lowBound <= $value) && ($value <= $highBound) ) {
sumbyelement( @array1, @array2 ), diffbyelement(@array1,@array2)
return the element-by-element sum or difference of two identically-sized vectors. Given
$s = sumbyelement( [10,20,30], [1,2,3] );
$d = diffbyelement( [10,20,30], [1,2,3] );
$s will be "[11,22,33]", $d will be "[9,18,27]".
allequal( @array1, @array2 )
returns true if and only if the two arrays are numerically identical.
convolute( @array1, @array2 )
return a reference to an array containing the element-by-element product of the two input arrays. I.e.,
$r = convolute( [1,2,3], [-1,2,1] );
returns a reference to
[-1,4,3]
median
evaluates the median, i.e. an element which separates the population in two halves. It returns a reference to a list whose first
element is the median value and the second element is the index of the median element in the original vector.
$a = Math::VecStat::median( [9,8,7,6,5,4,3,2,1] );
returns the list reference
[ 5, 4 ]
i.e. the median value is 5 and it is found at position 4 of the original array.
If there are several elements of the array having the median value, e.g. [1,3,3,3,5]. In this case we choose always the first element
in the original vector which is a median. In the example, we return [3,1]. =back =head1 HISTORY
$Log: VecStat.pm,v $
Revision 1.9 2003/04/20 00:49:00 spinellia@acm.org
Perl 5.8 broke test 36, exposing inconsistency in C<median>. Fixed, thanks to david@jamesgang.com.
Revision 1.8 2001/01/26 11:10:00 spinellia@acm.org
Added function median.
Fixed test, thanks to Andreas Marcel Riechert <riechert@pobox.com>
Revision 1.7 2000/10/24 15:28:00 spinellia@acm.org
Added functions allequal diffbyelement
Created a reasonable test suite.
Revision 1.6 2000/06/29 16:06:37 spinellia@acm.org
Added functions vecprod, convolute, sumbyelement
Revision 1.5 1997/02/26 17:20:37 willijar
Added line before pod header so pod2man installs man page correctly
Revision 1.4 1996/02/20 07:53:10 willijar
Added ability to return index in array contex to max and min
functions. Added minabs and maxabs functions.
Thanks to Mark Borges <mdb@cdc.noaa.gov> for these suggestions.
Revision 1.3 1996/01/06 11:03:30 willijar
Fixed stupid bug that crept into looping in min and max functions
Revision 1.2 1995/12/26 09:56:38 willijar
Oops - removed xy data functions.
Revision 1.1 1995/12/26 09:39:07 willijar
Initial revision
BUGS
Let me know. I welcome any appropriate additions for this package.
AUTHORS
John A.R. Williams <J.A.R.Williams@aston.ac.uk> Andrea Spinelli <spinellia@acm.org>
perl v5.12.4 2011-07-11 VecStat(3pm)