Ask-and-Tell Interface¶
SMAC provides an ask-and-tell interface in v2.0, giving the user the opportunity to ask for the next trial and report the results of the trial. However, the ask-and-tell interfaces comes in v2.0 with some limitations which you should be aware of.
Note
The initial design is already part of the ask and tell. Therefore, if you ask for the first trials, you will receive configurations from the initial design.
Warning
Using ask-and-tell instead of the optimize method might result in different results because some callbacks are ignored and skipped trials are handled differently. In fact, skipped trials are ignored completely and can results in being stuck when only skipped trials are found.
Please have a look at our ask-and-tell example.
Calling Tell without Ask¶
Sometimes you want to report pre-evaluated trials to the optimization. You can realize this by calling the
tell method without calling ask before. But be aware that this only works with the Intensifier and not
with Successive Halving or Hyperband. The Intensifier checks the run history and detects pre-evaluated
trials and incorporates it into the optimization. Since Successive Halving and Hyperband are more
complicated (needs specific budgets and pre-defined number of configurations in each stage), it is not supported yet.
Warning
Calling tell without ask does only work for specific intensifiers.
Calling Multiple Tells¶
Calling multiple times tell before ask is not supported yet.