What are the types of data structure and the access time in the best / average / worst cases? In a list is pretty simple, I need to run through all items until I find the specific one I wanted. What happens with facts? How do they store? Assume I have N facts: color(red). color(blue). . . . …

You should measure it for your use case I guess. There is quite a bit on the topic of how clauses are indexed here: https://www.swi-prolog.org/pldoc/man?section=jitindex

[image] moraneus: What are the types of data structure and the access time in the best / average / worst cases? See: Database micro-benchmark Obtaining Runtime Statistics

[image] moraneus: color(red). color So in my example above, when I query for color(green), it does hash lookup?

If I remember correctly, for less than ten clauses it does a linear search. This is the second bullet point in the link I shared above, “Linear scan on first argument”. If there are more colors than it is a hash lookup. You can also read the code I guess? I admit I haven’t done it myself. Maybe src…

Thank you :slightly_smiling_face:

[image] Boris: Maybe src/pl-index.c is the place to start reading? Not sure. Was looking for something else and saw predicate_property/2. The property indexed(Indexes) might be of use. Not sure as I did not try it, but if this were my question I would be checking this out.

[image] EricGT: Not sure as I did not try it, but if this were my question I would be checking this out. Use jiti_list/1 instead. The indexed(Indexes) property is specifically documented as might change. Of course, first call the relevant goals as they are Just In Time Indexes …

Access time and data structures

Help! Data Structure

EricGT August 31, 2020, 3:07pm 3

See:
Database micro-benchmark
Obtaining Runtime Statistics

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Access time and data structures

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