sutro-problems

Matrix Multiplication

Author: @jurajselep
Date: 2026-09-04
Problem: 4x4 matmul
Cost: 675
IR: best_675.ir
Verifier: best_675.py
SHA-256: 761d0401876c4c1fe8f51c0ff7ecf3676b7abca1f56b4e36715d70426d35427e

Summary

This submission lowers the 4x4 record from 681 to 675. Selective copies split the lifetimes of B[0,0], B[0,2], and A[0,3]; dependency-safe rescheduling and exact lifetime coloring then reduce the total read cost.

The IR uses 64 multiplications, 48 additions, and 16 copies.

Read source	Cost
mul	341
add	186
copy	80
outputs	68
total	675

Verification

python3 matmul/submissions/best_675.py