# medianw

## PURPOSE

Fast weighted median.

## SYNOPSIS

function m = medianw( x, w, dim )

## DESCRIPTION

     Fast weighted median.

     Computes the weighted median of a set of samples.
      http://en.wikipedia.org/wiki/Weighted_median
     "A weighted median of a sample is the 50% weighted percentile."
     For matrices computes median along each column (or dimension dim).
     If all weights are equal to 1 gives identical results to median.

     USAGE
      m = medianw( x, w, [dim] )

     INPUTS
      x      - vector or array of samples
      w      - vector or array of weights
      dim    - dimension along which to compute median

     OUTPUTS
      m      - weighted median value of x

     EXAMPLE - simple toy example
      x=[1 2 3]; w=[1 1 5]; medianw(x,w)

     EXAMPLE - comparison to median
      n=randi(100); m=randi(100);
      x=rand(n,m); w=ones(n,m);
      m1=median(x); m2=medianw(x,w);
      assert(isequal(m1,m2))

     See also median

     Piotr's Image&Video Toolbox      Version 3.24
     Copyright 2013 Piotr Dollar.  [pdollar-at-caltech.edu]
     Please email me if you find bugs, or have suggestions or questions!
     Licensed under the Simplified BSD License [see external/bsd.txt]