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[REBOL] Series comparison techniques

From: atruter::labyrinth::net::au at: 14-Aug-2003 13:56

Given the following code: <code> search-series: func [series [series!] operator [string!] value] [ clear rowids switch operator [ "=" [operator: :equal?] "<>" [operator: :not-equal?] "<" [operator: :lesser?] ">" [operator: :greater?] "<=" [operator: :lesser-or-equal?] ">=" [operator: :greater-or-equal?] "like" [operator: :find] ] start: now/time/precise repeat pos length? series [ if operator series/:pos value [insert tail rowids pos] ] print now/time/precise - start rowids ] max-rows: 100000 ;max-rows: 1000000 ;max-rows: 10000000 rowids: make block! max-rows block: make block! max-rows loop max-rows [insert tail block random 1000] </code> I was reasonably happy with the time taken to evaluate: search-series block "=" 1 for 100,000 1,000,000 and 10,000,000 values respectively (taking .14, 1.375 and 14 seconds on my Win2000 AMD1800XP 256Mb system). Increasing the data volumes by a factor of 10 increased the time taken by a similar amount. Since tests for equality are important, I added the following function to do this: <code> find-value: func [series [series!] value] [ clear rowids start: now/time/precise while [not none? series: find series value][ insert tail rowids index? series series: next series ] print now/time/precise - start rowids ] </code> and was [pleasantly] surprised to see that: find-value block 1 returned results in .015, .063 and .59 seconds respectively. Which got me thinking about *how* REBOL could do this given: 1) The series is not sorted 2) Values are not unique 3) Runtime increases at a lesser rate than data volume I am now wondering what other "clever" techniques / algorithms are available to handle other operators (eg. <>, <, >, etc) Thoughts? Regards, Ashley