VecStat(3pm) User Contributed Perl Documentation VecStat(3pm) 

    Math::VecStat - Some basic numeric stats on vectors


    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);

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.

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.
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.
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.
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.
return the sum of the given values or vector
return the average of the given values or vector
return a vector built by multiplying the scalar $a by each element of the @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) ) {
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]".

returns true if and only if the two arrays are numerically identical.
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]
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

Let me know. I welcome any appropriate additions for this package.

John A.R. Williams <J.A.R.Williams@aston.ac.uk> Andrea Spinelli <spinellia@acm.org>

2022-11-20 perl v5.36.0