(this page is a stub -- it contains info of new-to-4.0, but needs to be updated/reorganized to be a general reference page)

Declaration

Area( R : Numeric[J] ; I : ascending Numeric[J] ; X1,X2 : opt numeric atomic ; J : opt hidden IndexType = I )

With J not specified, I can be an index with numeric ascending values, or it can be a self-indexed array with arbitrary index values but with numeric ascending values along Self.

The J parameter also makes it possible to have an arbitrary X array:

Area( Y, X, J: In1)

where X and Y are arrays indexed by J (X must be ascending along J).

Some notes: J is hidden from the user, since the main concern was fixing several bugs with the function while maintaining backward compatibility. However, as the above example shows, it can be useful. The second parameter is named I for legacy reasons, but it would be better named X with the J parameter named I. Consider this change when updating manuals.

Another difference relative to 3.1 is that X2 (upper bound) can be specified while not specifying X1 (lower bound). So, for example, you could find the area up to a given point, e.g.:

var dens := Pdf(Ch1);
Area( dens, dens.Step, X2:x )