countwts
==============================================
Purpose
----------------
Returns a weighted count of the numbers of elements of a vector that fall into specified ranges.
Format
----------------
.. function:: c = countwts(x, v, w)
:param x: the numbers to be counted.
:type x: Nx1 vector
:param v: the breakpoints specifying the ranges within which counts are to be made. This MUST be sorted
in ascending order (lowest to highest).
:type v: Px1 vector
:param w: weights.
:type w: Nx1 vector
:return c: the weighted counts of the
elements of x that fall into the regions:
.. math::
x < v[1],\\
v[1] ≤ x < v[2],\\
\vdots\\
v[p-1] ≤ x < v[p]
That is, when :math:`x[i]` falls into region *j*, the weight
:math:`w[i]` is added to the jth counter.
:rtype c: Px1 vector
Examples
----------------
::
// Original data
x = { 1, 3, 2, 4, 1, 3 };
// Weights
w = { .25, 1, .333, .1, .25, 1 };
// Break points
v = { 0, 1, 2, 3, 4 };
// Get counts
c = countwts(x,v,w);
::
0.0000000
0.5000000
c = 0.3330000
2.0000000
0.1000000
Remarks
-------
If any elements of *x* are greater than the last element of *v*, they will
not be counted.
Missing values are not counted unless there is a missing in *v*. A missing
value in *v* MUST be the first element in *v*.