Bert Speelpenning

Computer scientist whose 1980 University of Illinois PhD thesis gave the first fully automatic software implementation of reverse-mode automatic differentiation, arrived at independently via compiler optimization rather than via Seppo Linnainmaa's earlier numerical-analysis line. Matters to this vault as the clearest single case of the AD field's own internal mutual-unawareness: the thesis that first automated the technique does not cite the mathematician who first described it a decade earlier.

References

• claim-speelpenning-1980-does-not-cite-linnainmaa
• claim-wengert-list-named-for-forward-mode-inventor — the "Wengert list" tape his implementation popularized is named for the forward-mode inventor, not for him
• claim-chainqueen-2019-full-reference-list-omits-ad-discovery-citations · claim-bolliger-2025-reference-list-omits-ad-discovery-names-names-jax-and-chainqueen · claim-difftaichi-2020-names-griewank-and-wengert-but-not-linnainmaa-or-speelpenning — added 2026-10-09: three further differentiable-physics papers (ChainQueen, Bolliger et al., DiffTaichi) computing the operation his thesis automated, none naming him
• claim-griewanks-name-reaches-differentiable-physics-literature-further-than-linnainmaas-or-speelpennings
• Captures: 10-inbox/raw/20260707-0924-speelpenning-1980-thesis-compiling, 10-inbox/raw/2026-10-05-does-chainqueen-2019-or-bolliger-et-al-2025.md