Transformation / Expression

Expression

The expression (or formula) used to define the Output of an Expression Transformation as a function of up to twenty Inputs, e.g., Input1 + Input2 + Input3.

Default: none.

Basis (3)

For an Expression Transformation which only defines one input, any costs arising from the used capacity of Resources used by that Transformation will be passed back directly to that input. More generally, these costs must be allocated between the various inputs. You can specify a set of proportions – one for each input – which weight the allocation of costs, according to the Basis input:

Fixed Proportions: costs are allocated according to the specified proportions, irrespective of the actual demand on the various Inputs.

Input Proportions: the proportions are scaled by the demand on the various Inputs, so that, for example, when the proportions are all 1, costs are allocated in direct proportion to the demand on each Input.

Note: you can allocate costs to a defined input, even if it does not appear explicitly in the Expression. Therefore you should take care to only define the inputs you actually require. By default, an un-referenced input will receive a share of costs, even if you aren't using it to calculate demand.

Default: Input Proportions.

Input

Identifies an element as a source of demand for a Transformation; together with a Basis, which specifies the particular result, associated with that element, which defines the size of that Input in any year. Expression Transformations have several inputs, called Input 1, Input 2, and so on.

Default: Resource (<none>, Installed Capacity). For an Erlang B Formula transformation, Service (<none>, Busy Hour Traffic). For a Time Factor transformation, Transformation (<none>).