Skip to content

Selector Shortcuts

As a reminder, a typical feedback definition looks like this:

f_lang_match = Feedback(hugs.language_match)
    .on_input_output()

on_input_output is one of many available shortcuts to simplify the selection of components for evaluation.

The selector, on_input_output, specifies how the language_match arguments are to be determined from an app record or app definition. The general form of this specification is done using on but several shorthands are provided. on_input_output states that the first two argument to language_match (text1 and text2) are to be the main app input and the main output, respectively.

Several utility methods starting with .on provide shorthands:

  • on_input(arg) == on_prompt(arg: Optional[str]) -- both specify that the next unspecified argument or arg should be the main app input.

  • on_output(arg) == on_response(arg: Optional[str]) -- specify that the next argument or arg should be the main app output.

  • on_input_output() == on_input().on_output() -- specifies that the first two arguments of implementation should be the main app input and main app output, respectively.

  • on_default() -- depending on signature of implementation uses either on_output() if it has a single argument, or on_input_output if it has two arguments.

Some wrappers include additional shorthands:

LlamaIndex specific selectors

  • TruLlama.select_source_nodes() -- outputs the selector of the source documents part of the engine output.

Usage:

from trulens_eval import TruLlama
source_nodes = TruLlama.select_source_nodes(query_engine)
  • TruLlama.select_context() -- outputs the selector of the context part of the engine output.

Usage:

from trulens_eval import TruLlama
context = TruLlama.select_context(query_engine)

LangChain specific selectors

  • TruChain.select_context() -- outputs the selector of the context part of the engine output.

Usage:

from trulens_eval import TruChain
context = TruChain.select_context(retriever_chain)

LlamaIndex and LangChain specific selectors

  • App.select_context() -- outputs the selector of the context part of the engine output. Can be used for both LlamaIndex and LangChain apps.

Usage:

from trulens_eval.app import App
context = App.select_context(rag_app)