Estimate a Scenario's Compute Cost and Longest Task

Predicts, before a scenario is launched, roughly how much compute it costs and how long its single longest task runs. It expands the scenario into its hc task table read-only (via ssd_scenario_hc_tasks(), without running any fit or bootstrap), applies the calibrated per-task cost model, and returns the ballpark serial total cost and the duration of the longest single task, plus a per-axis breakdown of which ci_method/nboot cells dominate.

Usage

ssd_estimate_cost(scenario, calibration = ssd_cost_calibration())

Arguments

scenario: An ssdsims_scenario from ssd_define_scenario().
calibration: An ssdsims_cost_calibration; defaults to the shipped ssd_cost_calibration(). Pass the result of ssd_calibrate_cost() for an architecture-specific estimate.

Value

An ssdsims_cost_estimate object: a list with total and longest (both difftime time quantities), a breakdown tibble grouped by ci_method x nboot, and the calibration's provenance.

Details

proportion and est_method are free axes: one bootstrap per nboot x ci_method x parametric cell serves every proportion/est_method, so adding values along those axes does not change the estimate. The estimator does not execute the scenario, draw random numbers, or alter any result.

The longest task is the irreducible wall-time floor under any amount of parallelism; wall-time under n workers is roughly max(longest_task, total / n), computed by the caller.

Examples

data <- ssd_scenario_data(ssddata::ccme_boron)
scenario <- ssd_define_scenario(
  data,
  nsim = 10L,
  seed = 42L,
  replace = TRUE,
  nrow = c(5L, 10L, 20L, 50L),
  ci = TRUE,
  nboot = c(1000L, 5000L, 10000L, 50000L)
)
ssd_estimate_cost(scenario)
#> <ssdsims_cost_estimate>  (ballpark, serial)
#>   total compute:  3.6 hours
#>   longest task:   6.1 min
#>   breakdown (ci_method x nboot, by total cost):
#>     weighted_samples   nboot  50000    40 tasks  2.7 hours
#>     weighted_samples   nboot  10000    40 tasks  32.6 min
#>     weighted_samples   nboot   5000    40 tasks  16.5 min
#>     weighted_samples   nboot   1000    40 tasks  3.6 min
#>   calibration:    Intel(R) Xeon(R) Processor @ 2.10GHz | R 4.5.3 | ssdtools 2.6.0.9002 | 2026-06-07
#>   Ballpark only - recalibrate with ssd_calibrate_cost() on the target machine.
#>