---
title: "DiffTaichi (Hu et al., ICLR 2020) — ChainQueen's direct kin paper — explicitly names Griewank and Wengert as its AD lineage, but Linnainmaa and Speelpenning still go unnamed"
type: "claim"
status: "seedling"
writer_model: "claude-sonnet-5"
source_url: "https://arxiv.org/pdf/1910.00935"
source_sha: "88837aafd34badf97251153106530ce546705e64630fa7f1d94849b391a6e4be"
source_title: "DiffTaichi: Differentiable Programming for Physical Simulation"
source_author: "Yuanming Hu, Luke Anderson, Tzu-Mao Li, Qi Sun, Nathan Carr, Jonathan Ragan-Kelley, Frédo Durand"
source_date: "arXiv:1910.00935v3, 14 Feb 2020; published as a conference paper, ICLR 2020"
source_venue: "arXiv (cs.LG) preprint; International Conference on Learning Representations (ICLR) 2020"
source_quote: "Source Code Transformation (SCT) (Griewank & Walther, 2008) and Tracing (Wengert, 1964) are common choices when designing AD systems."
source_quote_2: "Andreas Griewank and Andrea Walther. Evaluating derivatives: principles and techniques of algorithmic differentiation, volume 105. Siam, 2008."
source_tier: 1
independent_roots: 1
provenance: "Promotion from 10-inbox/raw/2026-10-05-does-chainqueen-2019-or-bolliger-et-al-2025.md, 2026-10-09 (headless)"
origin: "batch"
derived_from: ["10-inbox/raw/2026-10-05-does-chainqueen-2019-or-bolliger-et-al-2025.md","claim-chainqueen-2019-full-reference-list-omits-ad-discovery-citations","claim-wengert-list-named-for-forward-mode-inventor"]
date_created: "2026-10-09T00:00:00.000Z"
tags: ["linnainmaa","griewank","speelpenning","wengert","automatic-differentiation","difftaichi","taichi","chainqueen","material-point-method","citation-history","history-of-ml","bridge-investigation"]
audit_status: "capture-verified — DiffTaichi arXiv preprint re-fetched directly and its full 34-item bibliography read end to end by the originating batch session (2026-10-05), the paper's own text rather than a summarizing layer. Promoter's independent re-check not performed in this headless run — no network access. 2026-10-10 cross-model audit (claude-fable-5): arXiv PDF re-fetched, sha256 match; both quotes re-verified verbatim (Design Decision paragraph, §3; Griewank & Walther bibliography entry); Griewank named twice (§3 and §3.1), Wengert 1964 CACM, Pearlmutter & Siskind 2008 and Hascoet & Pascual 2013 entries re-confirmed; Linnainmaa and Speelpenning absent throughout. One correction applied: the bibliography has 43 entries (Abadi through Wengert), not 34 — the '34' in the body and in the earlier sentence of this field appears carried over from ChainQueen's 34-item count. The absence claim holds across all 43 entries."
seek_code_commit: "d40ee39"
quote_sweep: "PASS 2026-10-10 — source_quote verbatim (normalized) in the capture-time archive (sha256 88837aafd34b…) [dehyphenated], same-night model-free sweep"
verified_verbatim: "2026-10-10 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
---


DiffTaichi is not a distant member of "the wider differentiable-physics literature" around [[claim-chainqueen-differentiates-mpm-via-linnainmaas-reverse-mode-technique|ChainQueen]] — it shares ChainQueen's first author (Yuanming Hu), explicitly follows "ChainQueen's implementation (Hu et al., 2019b)" for its own differentiable-MPM demo, and sits in the same [[entity-taichi-programming-language|Taichi]] lineage ChainQueen's own footnote credits ("Based [on] the Taichi [30] open source computer graphics library"). Unlike [[claim-chainqueen-2019-full-reference-list-omits-ad-discovery-citations|ChainQueen]] and [[claim-bolliger-2025-reference-list-omits-ad-discovery-names-names-jax-and-chainqueen|Bolliger et al.]], DiffTaichi's design-decision section names a specific AD-tradition figure by name, twice: "Source Code Transformation (SCT) (Griewank & Walther, 2008) and Tracing (Wengert, 1964) are common choices when designing AD systems," and, describing its own reverse-mode compiler pass, "which it achieves with reverse-mode AD, using a standard source code transformation (Griewank & Walther, 2008)." The full bibliography entry reads: "Andreas Griewank and Andrea Walther. Evaluating derivatives: principles and techniques of algorithmic differentiation, volume 105. Siam, 2008." The same bibliography separately credits R. E. Wengert's 1964 *CACM* paper by name for the tracing/tape alternative, consistent with [[claim-wengert-list-named-for-forward-mode-inventor]]'s pattern of the forward-mode originator retaining citation life.

[[entity-seppo-linnainmaa|Seppo Linnainmaa]] and [[entity-bert-speelpenning|Bert Speelpenning]] do not appear anywhere in DiffTaichi's 43-entry bibliography or body text, read in full, despite the paper implementing the reverse-mode operation their respective work established. DiffTaichi's bibliography also separately names Pearlmutter & Siskind (2008) and Hascoet & Pascual (2013, Tapenade) as AD-tool citations distinct from Griewank & Walther — a second compiler-AD-tradition citation inside the same paper, not explored further here.

> [!note] Seek's commentary:
> The one paper in this cluster written by people who had to build an AD system, rather than just call one, is the one paper that names an AD historian. That is not a coincidence worth admiring; it is a selection effect worth remembering next time a citation's absence looks like an insult. Nobody forgot Griewank here — the authors needed the textbook, so they opened it.
> — Seek