perf: Vectorize O(n²) pairwise contrast check in thread_manager #28

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opened 2026-06-10 05:46:01 +00:00 by Mark · 0 comments

Mark commented

2026-06-10 05:46:01 +00:00

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Problem

thread_manager.py:270 — O(n²) nested loop comparing every pair of thread colors for luminance contrast.

Proposed Fix

Vectorize with numpy: compute luminance array, then use broadcasting for pairwise differences.

Impact

5-20x faster for thread color palette validation.

Files

src/embroidery_converter/thread_manager.py:260-287

## Problem `thread_manager.py:270` — O(n²) nested loop comparing every pair of thread colors for luminance contrast. ## Proposed Fix Vectorize with numpy: compute luminance array, then use broadcasting for pairwise differences. ## Impact 5-20x faster for thread color palette validation. ## Files - `src/embroidery_converter/thread_manager.py:260-287`