perf: single-pass std.sum/std.avg without intermediate array#782
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stephenamar-db merged 1 commit intodatabricks:masterfrom Apr 21, 2026
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Motivation: std.sum and std.avg perform three passes over the input array: forall (validate) → map (allocate intermediate Array[Double]) → sum. Modification: Replace with a single while-loop that validates types and accumulates in one pass. No intermediate array allocation. Result: Eliminates O(n) Array[Double] allocation and two redundant iterations for every std.sum/std.avg call.
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Summary
forallvalidate →.map(_.value.asDouble)allocate intermediateArray[Double]→.sumaccumulate) with a single while-loop that validates + accumulates in one passArray[Double]allocation entirelystd.sumandstd.avgChanges
ArrayModule.scala: Rewritestd.sumandstd.avgto use single-pass while-loop with pattern matching for validation + accumulationTest plan
./mill 'sjsonnet.jvm[3.3.7]'.test— all tests pass./mill 'sjsonnet.jvm[3.3.7]'.compile— compiles cleanstd.sum expected number/Cannot calculate average of an empty array