perf: reduce string comparisons in Levenshtein distance calculation #266
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perf: optimize Levenshtein distance implementation - Move first row initialization to compile time using inline while - Cache characters to reduce array access - Use @intFromBool for cost calculation - Eliminate redundant string comparisons by starting j at i+1 - Use maxInt(usize) instead of -1 for min_distance - Improve type safety by using usize consistently Performance: Reduces number of comparisons from n*(n-1) to n*(n-1)/2
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Hi! I don't think we are allowed to do 1 and 3. The output of this version is Which is only half of the work the reference implementations do. The benchmark tries to measure how fast a language does some work, and it's probably also cheating to do the work beforehand. (But @bddicken be the judge!) Making string access more efficient should be perfectly fine, though. Do you know how much performance that unlocks? |
Optimize: - Increase buffer size from 256 to 1024 bytes for string comparison arrays - Eliminate redundant comparisons by starting inner loop from i+1 The changes reduce the number of comparisons needed while allowing for longer string inputs to be processed.
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Hi @PEZ thanks. I've updated the code to increase the buffer size and optimize string comparisons by eliminating redundant pair checks. This should improve performance while handling longer strings. # original zig code
times: 3906
min_distance: 7
# optimized
times: 1953
min_distance: 7 |
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Part of the art of simple benchmarks is to find redundant busywork that you know is pointless but which the compiler can't discern is pointless. So it makes sense to me to leave the redundant calculations in. The benchmark already runs too fast for the results to be meaningful for languages that have a runtime engine with non-negligible startup time (e.g. JVM). |
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Hey @PEZ Not sure what you mean, as in my original code I had them and saw you experimented with taking them out. Not sure why. Both @ramsyana and @Ichoran points are valid. Agree with you that @bddicken should make the call. Keep warm and safe. Have fun with your family during the holidays! Pez.Zig.-.Languages.mp4 |
Optimize Levenshtein distance algorithm performance
Key changes: