Collects one or more ssd_define_scenario() scenarios into a validated, named
collection - the design (design-of-experiments sense: the set of
conditions to run), the union of regular per-scenario grids into one
possibly-non-regular design. The design is turned into a single targets
pipeline by ssd_design_targets().
Arguments
- ...
One or more
ssdsims_scenarioobjects fromssd_define_scenario(), optionally named.
Details
Names are taken from the argument names where supplied, otherwise derived from
the argument expression by symbol capture (e.g. a variable base becomes
"base"), mirroring ssd_scenario_data(). Each name is a scenario name
within the design, used only as the scenario identity column in the combined
summary and the per-scenario summary target-name suffix - never in a shard
path, a shard target name, the per-task primer, or any result value. Names must
be unique, non-empty, and safe to serve as a target-name suffix (start with a
letter; letters, digits, and underscore only). A design of one scenario is
valid and uniformly shaped - the recommended starting point for a study that
may grow (see the migration vignette).
Consistency contract
Because ssd_design_targets() addresses shards by cell and shares a cell
across members (computing it once), the same name must denote the same
value across members, or two members could disagree on a shared cell's bytes.
ssd_design() therefore validates across members that the same dataset name
binds identical data, the same min_pmix name binds an identical function, the
same distset name binds identical members, and that partition_by is
identical - aborting with an informative error otherwise. The seed may vary
across members (it becomes a seed= results level); members sharing a seed
share their coincident cells (common random numbers).
Examples
data <- ssd_scenario_data(ssddata::ccme_boron)
coarse <- ssd_define_scenario(data, nsim = 2L, seed = 42L, nrow = c(5L, 10L))
dense <- ssd_define_scenario(data, nsim = 2L, seed = 42L, nrow = c(6L, 7L, 8L))
ssd_design(coarse, dense)
#> <ssdsims_design>
#> scenarios: 2
#> coarse (seed 42)
#> dense (seed 42)