** Next:** 3.6.3 The Curve-To-File-Model
**Up:** 3.6 Auxiliary Models
** Previous:** 3.6.1 The Arithmetic-Model

The **curve-calculator-model**
(Figure 3.7,
Description 3.6) is able to perform arithmetic
operations between corresponding operating points of structurally
identical input curves, similar to the
**arithmetic-model**. Example 3.4 demonstrates this
behavior. The operator `diff` computes the difference of each
curve response which exists in the curve at input port *a* as
well as in the curve at input port *b*. The resulting curve,
which can be considered the difference between the two input curves,
is delivered at the output port named *diff*. Unless the
structures of the involved curves are not identical *SIESTA* issues
an error message.

*Rudi Strasser *

1999-05-27