25.5 Some mathematical-support related objects

INTEGRATOR OBJECTS
Integrator Objects support the approximate computation of continuous
integrals using discrete sums. The running sum(integral) is computed as:
`sum_ += [lasty_ * (x lastx_)]` where (x, y) is the last element
entered and
(lastx_, lasty_) was the element previous to that added to the sum.
lastx_ and lasty_ are updated as new elements are added. The first
sample point defaults to (0,0) that can be changed by changing the values
of (lastx_,lasty_).
`$integrator newpoint x y`

Add the point (x,y) to the sum. Note that it does not make sense for x to
be less than lastx_.

There are no configuration parameters specific to this object.

State Variables are:

**lastx_**- x-coordinate of the last sample point.
**lasty_**- y-coordinate of the last sample point.
**sum_**- Running sum (i.e. the integral) of the sample points.

SAMPLES OBJECT Samples Objects support the computation of mean and variance statistics for a given sample.

`$samples mean`

Returns mean of the sample.

`$samples variance`

Returns variance of the sample.

`$samples cnt`

Returns a count of the sample points considered.

`$samples reset `

Reset the Samples object to monitor a fresh set of samples.

There are no configuration parameters or state variables specific to this object.

Tom Henderson 2011-11-05