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 [email protected] Perl 5.8 broke test 36, exposing inconsistency in C<median>. Fixed, thanks to [email protected]. Revision 1.8 2001/01/26 11:10:00 [email protected] Added function median. Fixed test, thanks to Andreas Marcel Riechert <[email protected]> Revision 1.7 2000/10/24 15:28:00 [email protected] Added functions allequal diffbyelement Created a reasonable test suite. Revision 1.6 2000/06/29 16:06:37 [email protected] 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 <[email protected]> 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