NUMEL NUMEL Number of Elements in an Array

Usage

Returns the number of elements in an array x, or in a subindex
expression.  The syntax for its use is either

   y = numel(x)

or 

   y = numel(x,varargin)

Generally, numel returns prod(size(x)), the number of total
elements in x.  However, you can specify a number of indexing
expressions for varagin such as index1, index2, ..., indexm.
In that case, the output of numel is 
prod(size(x(index1,...,indexm))).