Cost Estimation

The Pico emulator also provides a method for obtaining a rough estimate for the answer to the question: how many CPU cycles would it take to prove this trace? This is done by setting the EmulatorOpts::cost_estimator flag to true or by using EmulatorOpts::with_cost_estimator. This produces a value in the host_cycle_estimator field of the EmulationReport per batch, and the Vec entries of type CycleEstimator can be used to estimate the cycles on a given model. Each entry corresponds to the chunk index within the specific batch. The current model used by Pico is present in model.json, found at the root of the repository, and can be loaded with EstimatorModel::from_json(path). By using the estimator data with different models of host prover, different numbers may be obtained.

Currently, the Pico model universally divides the estimator result by 1000 as a means to avoid overflow. This is subject to change.