
{{alias}}( W[, mx, my] )
    Returns an accumulator function which incrementally computes a moving
    sample absolute Pearson product-moment correlation coefficient.

    The `W` parameter defines the number of values over which to compute the
    moving sample absolute correlation coefficient.

    If provided values, the accumulator function returns an updated moving
    sample absolute correlation coefficient. If not provided values, the
    accumulator function returns the current moving sample absolute correlation
    coefficient.

    As `W` (x,y) pairs are needed to fill the window buffer, the first `W-1`
    returned values are calculated from smaller sample sizes. Until the window
    is full, each returned value is calculated from all provided values.

    Parameters
    ----------
    W: integer
        Window size.

    mx: number (optional)
        Known mean.

    my: number (optional)
        Known mean.

    Returns
    -------
    acc: Function
        Accumulator function.

    Examples
    --------
    > var accumulator = {{alias}}( 3 );
    > var ar = accumulator()
    null
    > ar = accumulator( 2.0, 1.0 )
    0.0
    > ar = accumulator( -5.0, 3.14 )
    ~1.0
    > ar = accumulator( 3.0, -1.0 )
    ~0.925
    > ar = accumulator( 5.0, -9.5 )
    ~0.863
    > ar = accumulator()
    ~0.863

    See Also
    --------

