Fields

Field operators are defined by using the .field operator when suffixed on a term or other operator. Field names should be specified in lower case in queries.

Field Restriction and Evaluation

Name	Example	Behavior
Restriction	dog.title	counts only occurrences of dog in title field
	dog.title,header	counts occurrences of dog in title or header
Evaluation	dog.(title)	builds belief b(dog) using "title" language model
	dog.(title,header)	b(dog) estimated using language model from concatenation of all title and header fields
	#od1(trevor strohman).person(title)	builds a model from all title text for b(#od1(trevor strohman).person) - only counts "trevor strohman" occurrences in person fields

Passage Retrieval

You can also use the fields for retrieval of passages within the corpus.

Name	Example	Behavior
field retrieval	#combine[title]( query )	Return only title fields ranked according to #combine(query) (beliefs are estimated on each title’s language model and may use any belief node)
passage retrieval	#combine[passage200:100]( query )	dynamically created passages of length 200 created every 100 words are ranked by #combine(query)
	#combine[section]( bootstrap #combine[./title]( methodology ))	Rank sections matching bootstrap where the section’s title also matches methodology. Note that you can use .//field for ancestor and .\field for parent.

[thiziri belkacem]

Hi David,
I would like to rank documents based on their titles using the Okapi baseline.
I've indexed the Gov2 dataset and specified the "title" as a content to be indexed using the "field" label.
I've tried to perform ranking with an example query using the following command line:

runquery/IndriRunQuery -query="#combine[title](tv program)" -count=10 -index=/path/to/gov2_index  -trecFormat=true -baseline=okapi

But Igot the following error:

kstem_add_table_entry: Duplicate word emeritus will be ignored.
# EXCEPTION in query 0: IndriRunQuery.cpp(645): Can't run baseline on this query: #combine[title](tv program)

It seems like it doesn't work with the baselines.
How can I do the same thing with the baselines ?
Thanks
Thiziri