Direct Approximation of a Function or its Inverse
- By far the most efficient approach for a fixed accuracy criterion,
- Maximum flexibility in efficiency vs. accuracy tradeoffs,
- Can use piecewise approximation for increased efficiency.
- More difficult to include ERM parameters as variables,
- Requires non-linear approximation tools to get coefficients,
- Requires considerable analyst experience and intuition.
and once the ERM is fixed, becomes
where the Ci are constants.