Definition of Term: Code uncertainty

An emulator is a probabilistic representation of the output(s) of a simulator. For any given input configuration the output is uncertain (unless this input configuration was included in the training sample). This uncertainty is known as code uncertainty. The emulator defines exactly what the code uncertainty is about the output(s) from any given configuration(s) of inputs.

Because the output(s) are uncertain, we are also uncertain about properties of those outputs, such as the uncertainty mean in an uncertainty analysis. The code uncertainty expressed in the emulator then implies code uncertainty about the properties of interest. Statements that we can make about those properties are therefore inferences. For instance, we may estimate a property by its mean, which is evaluated with respect to its code uncertainty distribution.