Archives : ezyang’s blog

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Draw high dimensional tensors as a matrix of matrices (October 25, 2025)
So you want to control flow in PT2 (September 5, 2025)
The Parallelism Mesh Zoo (August 30, 2025)
You could have invented CuTe hierarchical layout (but maybe not the rest of it?) (August 22, 2025)
State of torch.compile for training (August 2025) (August 13, 2025)
Vibe coding case study: ScubaDuck (June 2, 2025)
Why you should maintain a personal LLM coding benchmark (April 4, 2025)
New Years resolutions for PyTorch in 2025 (January 9, 2025)
Ways to use torch.export (December 23, 2024)
Ways to use torch.compile (November 5, 2024)
Tensor programming for databases, with first class dimensions (October 14, 2024)
What’s different this time? LLM edition (October 4, 2024)
Interactive scraping with Jupyter and Puppeteer (November 23, 2021)
PyTorch Developer Podcast (May 5, 2021)
Rage bug reporting (April 25, 2021)
The PyTorch open source process (January 6, 2021)
The hidden problem(?) with basic block procedures in SSA (October 24, 2020)
Idiomatic algebraic data types in Python with dataclasses and Union (October 14, 2020)
Let’s talk about the PyTorch dispatcher (September 10, 2020)
Dynamic scoping is an effect, implicit parameters are a coeffect (August 27, 2020)
A brief taxonomy of PyTorch operators by shape behavior (May 6, 2020)
vmap in Haskell (January 29, 2020)
PyTorch internals (May 16, 2019)
A short note about functional linear maps (May 15, 2019)
Microsoft Surface Book 2 (March 17, 2019)
HIW’18: Let’s Go Mainstream with Eta! (September 23, 2018)
A year into Backpack (July 14, 2018)
A compile-time debugger that helps you write tensor shape checks (April 6, 2018)
Online/offline continuous integration (March 12, 2018)
Semantic Import Versioning in the wild (February 23, 2018)
Systems ML workshop panel (December 8, 2017)
Accelerating Persistent Neural Networks at Datacenter Scale (Daniel Lo) (December 8, 2017)
MOCHA: Federated Multi-Tasks Learning (Virginia Smith) (December 8, 2017)
A Machine Learning Approach to Database Indexes (Alex Beutel) (December 8, 2017)
Ray: A Distributed Execution Framework for Emerging AI Applications (Ion Stoica) (December 8, 2017)
Backpack for deep learning (August 17, 2017)
Proposal: Suggest explicit type application for Foldable length and friends (March 21, 2017)
Prio: Private, Robust, and Scalable Computation of Aggregate Statistics (March 17, 2017)
Designing the Backpack signature ecosystem (March 11, 2017)
How to integrate GHC API programs with Cabal (February 8, 2017)
Try Backpack: Cabal packages (January 17, 2017)
A tale of backwards compatibility in ASTs (December 31, 2016)
Backpack and the PVP (December 30, 2016)
Left-recursive parsing of Haskell imports and declarations (December 21, 2016)
The problem of reusable and composable specifications (December 17, 2016)
Thoughts about Spec-ulation (Rich Hickey) (December 16, 2016)
Try Backpack: ghc --backpack (October 10, 2016)
Seize the Means of Production (of APIs) (September 13, 2016)
The Base of a String Theory for Haskell (September 7, 2016)
The Edit-Recompile Manager (September 2, 2016)
Backpack and separate compilation (September 1, 2016)
cabal new-build is a package manager (August 29, 2016)
Optimizing incremental compilation (August 27, 2016)
What Template Haskell gets wrong and Racket gets right (July 18, 2016)
Debugging tcIfaceGlobal errors in GHC: a study in interpreting trace output (May 15, 2016)
Announcing cabal new-build: Nix-style local builds (May 2, 2016)
Hindley-Milner with top-level existentials (April 24, 2016)
ghc-shake: Reimplementing ghc --make (January 7, 2016)
The convergence of compilers, build systems and package managers (December 7, 2015)
What is Stateless User Interface? (November 27, 2015)
Is no-reinstall Cabal coming to GHC 8.0? (September 18, 2015)
Help us beta test “no-reinstall Cabal” (August 29, 2015)
Ubuntu Vivid upgrade (Xmonad) (May 29, 2015)
Width-adaptive XMonad layout (May 2, 2015)
An Eq instance for non de Bruijn terms (January 30, 2015)
Unintended consequences: Bound threads and unsafe FFI calls (December 8, 2014)
Ubuntu Utopic upgrade (Xmonad) (December 4, 2014)
Tomatoes are a subtype of vegetables (November 14, 2014)
Haskell Implementor’s Workshop ’14 (September 7, 2014)
Open type families are not modular (September 4, 2014)
A taste of Cabalized Backpack (August 26, 2014)
The fundamental problem of programming language package management (August 21, 2014)
What’s a module system good for anyway? (August 9, 2014)
New theme! (July 26, 2014)
Type classes: confluence, coherence and global uniqueness (July 11, 2014)
Parsec: “try a <|> b” considered harmful (May 17, 2014)
GHC and mutable arrays: a DIRTY little secret (May 9, 2014)
Elimination with a Motive (in Coq) (May 7, 2014)
The cost of weak pointers and finalizers in GHC (May 4, 2014)
Calculating Shanten in Mahjong (April 1, 2014)
Haskell for Coq programmers (March 17, 2014)
Equality, roughly speaking (January 30, 2014)
How to maintain a pristine copy of your configuration files (January 20, 2014)
PEPM’14: The HERMIT in the Stream (January 17, 2014)
Ott ⇔ PLT Redex (January 13, 2014)
When a lock is better than an MVar (January 7, 2014)
So you want to add a new concurrency primitive to GHC… (January 1, 2014)
Two bugs in the borrow checker every Rust developer should know about (December 17, 2013)
Visualizing a block allocator (October 30, 2013)
Xmonad and media keys on Saucy (October 27, 2013)
If you’re using lift, you’re doing it wrong (probably) (September 26, 2013)
Of Monadic Fixpoints and Heap Offsets (September 24, 2013)
Induction and logical relations (September 18, 2013)
Cost semantics for STG in modern GHC (September 7, 2013)
Blame Trees (August 12, 2013)
OPLSS lecture notes (July 29, 2013)
No grammar? No problem! (July 2, 2013)
HoTT exercises in Coq (in progress) (July 1, 2013)
(Homotopy) Type Theory: Chapter One (June 24, 2013)
The AST Typing Problem (May 28, 2013)
Anatomy of an MVar operation (May 19, 2013)
HotOS “Unconference” report:
Verifying Systems (May 14, 2013)
Category theory for loop optimizations (May 12, 2013)
The Difference between Recursion & Induction (April 27, 2013)
Kindle is not good for textbooks (April 15, 2013)
A Zerocoin puzzle (April 11, 2013)
A classical logic fairy tale (April 7, 2013)
NDSEG (April 5, 2013)
Resource limits for Haskell (April 2, 2013)
The single export pattern (March 31, 2013)
The duality of weak maps and private symbols (March 19, 2013)
What is a membrane? (March 15, 2013)
Kindle Paperwhite notes (January 30, 2013)
The GHC scheduler (January 28, 2013)
NLP: the missing framework (January 2, 2013)
Google Nexus 7 setup notes (December 31, 2012)
Metro Maps of the News (December 13, 2012)
Maildir synchronizing Sup (December 1, 2012)
Why can’t I just be a little lazy? (November 26, 2012)
Functional Encryption (November 25, 2012)
Extremist Programming (November 20, 2012)
Plan 9 mounts and dependency injection (November 8, 2012)
hp/D3.js: an interactive heap profile viewer (November 2, 2012)
Ubuntu Quantal upgrade (Thinkpad/Xmonad) (October 24, 2012)
ACM XRDS: Jeff Dean profile (October 22, 2012)
Duality for Haskellers (October 19, 2012)
Hails: Protecting Data Privacy in Untrusted Web Applications (October 16, 2012)
Visualizing satisfiability, validity & entailment (October 15, 2012)
GET /browser.exe (October 12, 2012)
Generalizing the programmable semicolon (October 3, 2012)
Template project for GHC plugins (September 28, 2012)
“This is really the End.” (September 24, 2012)
Unintuitive facts about Safe Haskell (September 17, 2012)
The Y Combinator and strict positivity (September 12, 2012)
So you want to hack on IMAP… (August 31, 2012)
OfflineIMAP sucks (August 30, 2012)
How OfflineIMAP works (August 27, 2012)
The Monad Reader: Issue 20 (August 25, 2012)
Applicative functors (August 16, 2012)
Practical Foundations for Programming Languages (first impressions) (August 15, 2012)
Is Haskell liberal or conservative? (August 10, 2012)
Two ways of representing perfect binary trees (August 4, 2012)
Polymorphic variants in Ur/Web (July 29, 2012)
Managing the server/client split in Ur/Web (July 25, 2012)
Secure multiparty Bitcoin anonymization (July 20, 2012)
Why verification results in higher quality code (June 23, 2012)
Thoughts on gamifying textbooks (May 24, 2012)
An Interactive Tutorial of the Sequent Calculus (May 22, 2012)
Ubuntu Precise upgrade (Thinkpad/Xmonad) (May 18, 2012)
What happens when you mix three research programming languages together (May 16, 2012)
Some thoughts about literature review (May 13, 2012)
How Ur/Web records work and what it might mean for Haskell (April 20, 2012)
Use the source, don’t read it (April 17, 2012)
Reduce Ubuntu latency by disabling mDNS (March 24, 2012)
Visit month: Princeton (March 20, 2012)
Is it better to teach formalism or intuition? (March 18, 2012)
Visit month: University of Pennsylvania (March 16, 2012)
You could have invented fractional cascading (March 5, 2012)
Visualizing range trees (February 26, 2012)
Anatomy of “You could have invented…” (February 23, 2012)
Transcript of “Inventing on Principle” (February 20, 2012)
Travel: Spring 2012 Edition (February 18, 2012)
How to build DRM you can trust (February 15, 2012)
POPL (January 28, 2012)
Modelling IO: MonadIO and beyond (January 24, 2012)
monad-control is tricky (January 23, 2012)
Mystery Hunt and the Scientific Endeavour (January 16, 2012)
Problem Set: The Codensity Transformation (January 7, 2012)
Why iteratees are hard to understand (January 4, 2012)
Bugs and Battleships (December 19, 2011)
How to build i686 glibc on Ubuntu (December 18, 2011)
Interactive Demo of Zero-Knowledge Proofs (December 17, 2011)
Accessing lazy structures from C (December 15, 2011)
Transparent xmobar (November 28, 2011)
Ubuntu Oneiric upgrade (Thinkpad/Xmonad) (November 24, 2011)
How to read Haskell like Python (November 14, 2011)
The new Reflections on Trusting Trust (October 28, 2011)
Obviously Correct (October 24, 2011)
Polyglot programming (October 12, 2011)
Why you shouldn’t do a PhD in systems (September 26, 2011)
Let’s play a game (September 5, 2011)
8 ways to report errors in Haskell revisited (August 29, 2011)
Joseph and the Amazing Technicolor Box (August 23, 2011)
Diskless Paxos crash recovery (August 14, 2011)
First impressions of module programming (August 5, 2011)
In-program GC stats redux (August 3, 2011)
Changes to IntMap (August 1, 2011)
Food-related functional humor (July 29, 2011)
BlockedIndefinitelyOnMVar (July 27, 2011)
From data type definitions to code (July 25, 2011)
Variant types and GADTs (July 22, 2011)
In-program GC stats for GHC (July 20, 2011)
Synthetic Git merges (July 18, 2011)
Parallelism to plug space leaks (July 15, 2011)
Facebook support for BarnOwl (July 13, 2011)
Grad School, Oh My (July 11, 2011)
Cambridge retrospective: History and Philosophy of Science (July 8, 2011)
A new vision for Mendeley (July 6, 2011)
IVar leaks (July 4, 2011)
Scheduling IVars (July 1, 2011)
The IVar monad (June 29, 2011)
Debugging compilers with optimization fuel (June 27, 2011)
Multi-monitor xmobar placement on Gnome (June 24, 2011)
A Year of Notebooking (Part 2) (June 22, 2011)
A Year of Notebooking (Part 1) (June 20, 2011)
A pattern for increasing sharing (June 17, 2011)
On type synonyms (June 15, 2011)
A Taxonomy of Socialization on the Internet (June 13, 2011)
Pinpointing space leaks in big programs (June 10, 2011)
Measurement, quantification and reduction (June 8, 2011)
What Philosophy of Science Can Say for Software Engineers (June 6, 2011)
The Cryptography of Bitcoin (June 3, 2011)
Bitcoin is not decentralized (June 1, 2011)
Chain Rule + Dynamic Programming
= Neural Networks (May 30, 2011)
An insufficiently lazy map (May 27, 2011)
If it has lots of comments, it’s probably buggy (May 25, 2011)
Tail recursion makes your loops cleaner (May 23, 2011)
Computing function composition (May 20, 2011)
Anatomy of a thunk leak (May 18, 2011)
Space leak zoo (May 16, 2011)
Reified laziness (May 13, 2011)
Calling all space leaks (May 11, 2011)
Bindings and CAFs on the Haskell Heap (May 9, 2011)
How Aristotle got it Wrong
On the importance of conceptual frameworks (May 6, 2011)
Unraveling the mystery of the IO monad (May 4, 2011)
Haskell: Not pure enough? (May 2, 2011)
How the Grinch stole the Haskell Heap (April 29, 2011)
Functions produce the Haskell Heap (April 27, 2011)
Implementing the Haskell Heap in Python, v1 (April 25, 2011)
IO evaluates the Haskell Heap (April 24, 2011)
Evaluation on the Haskell Heap (April 20, 2011)
The Haskell Heap (April 18, 2011)
Mailbox: Advice for a sup first-timer (April 16, 2011)
Tracing the compilation of Hello Factorial! (April 13, 2011)
Bugs from using the wrong variable (April 11, 2011)
Hoopl: Dataflow analysis (April 8, 2011)
Type Kata: Local data type (April 5, 2011)
Hoopl: Dataflow lattices (April 4, 2011)
Hoopl guided tour: Base system (April 1, 2011)
GHC migrating to Git (March 30, 2011)
HTML Purifier 4.3.0 released (March 28, 2011)
Ely Cycles (March 25, 2011)
Interleaving stream processors (March 23, 2011)
The return of Hellenistic reasoning (March 21, 2011)
Spring Reading: 2011 edition (March 18, 2011)
On expressivity (March 16, 2011)
Someone is wrong on the Internet (March 14, 2011)
Many-valued logics and bottom (March 11, 2011)
Killer mutants attack (mutation gone wrong) (March 9, 2011)
Type Technology Tree (March 7, 2011)
Petri net concurrency (March 4, 2011)
The creation of a statically-typed functional programmer (March 2, 2011)
On cargo culting and hacking (February 28, 2011)
Multi-day debugging (February 25, 2011)
Ad hoc approximations (February 23, 2011)
Semi-automatic testing (February 21, 2011)
Two short tips for FFI bindings (February 20, 2011)
On checked exceptions and proof obligations (February 18, 2011)
Picturing Hoopl transfer/rewrite functions (February 16, 2011)
Picturing binomial coefficient identities (February 14, 2011)
Android 2.x Sensor Simulator (February 11, 2011)
A suggestion for indent/php.vim (February 9, 2011)
Lav’net is watching you (February 7, 2011)
OCaml gotchas (February 4, 2011)
All about MVars (February 2, 2011)
A year of blogging (December 31, 2010)
Greetings from Switzerland (December 29, 2010)
No one expects the Scott induction! (December 27, 2010)
Thriller: Doing it for the thrills (December 24, 2010)
Travel advisory (December 21, 2010)
Generalization and vagueness in specifications (December 20, 2010)
Tourist by day, Blogger by night (December 17, 2010)
ω: I’m lubbin’ it (December 15, 2010)
Getting a fix on fixpoints (December 13, 2010)
Errata for gin and monotonic (December 10, 2010)
Gin and monotonic (December 8, 2010)
Hussling Haskell types into Hasse diagrams (December 6, 2010)
Talk Friday (December 3, 2010)
How I Learned to Stop Worrying and Love the ⊥ (December 1, 2010)
My first proof in Isabelle (November 29, 2010)
Reflexivity. Qed. (November 26, 2010)
Integer sequences every computer scientist should know? (November 24, 2010)
Is multiply-carry strongly universal? (November 22, 2010)
Cambridge potpourri (November 19, 2010)
Haskell.org committee (November 17, 2010)
It’s just a longjmp to the left (November 15, 2010)
You are in a maze of twisty little passages, all alike… (a GHC hacking post) (November 12, 2010)
mod_fcgid 2.3 is broken (fixed in 2.3.6) (November 10, 2010)
Medieval medicine and computers (November 8, 2010)
DP Zoo Tour (November 5, 2010)
Dead Edward Day (November 3, 2010)
DP Zoo (November 1, 2010)
Intelligence is the ability to make finer distinctions: Another Haskell Advocacy Post (October 29, 2010)
Blog name changed… (October 27, 2010)
OCaml for Haskellers (October 25, 2010)
Don’t Repeat Yourself is context dependent (October 22, 2010)
Purpose of proof: semi-formal methods (October 20, 2010)
Rapidly prototyping scripts in Haskell (October 18, 2010)
Existential type-curry (October 15, 2010)
Quote Day (October 13, 2010)
Why being a sysadmin will help you do Science! (October 11, 2010)
The HTML purification manifesto (October 8, 2010)
Abstraction without a concrete concept (October 6, 2010)
Why I am in Cambridge (October 4, 2010)
Tips for running a hackathon (October 1, 2010)
How to get answers from busy maintainers (September 29, 2010)
So long America! (September 27, 2010)
High performance monads (September 24, 2010)
Data is Code (September 22, 2010)
Tension of patch and tree version control (September 20, 2010)
Session types, subtyping and dependent types (September 17, 2010)
Evolution of a Shared Web Host (September 15, 2010)
Keyword arguments in Haskell (September 13, 2010)
Towards platform-agnostic interruptibility (September 10, 2010)
pthread_cancel on Windows (September 8, 2010)
Embracing Windows (September 6, 2010)
Annotating slides (September 3, 2010)
My type signature overfloweth (September 1, 2010)
Defining "Haskelly" (August 30, 2010)
Interrupting GHC (August 27, 2010)
abcBridge: Functional interfaces for AIGs and SAT solving (August 25, 2010)
Type Kata: Distinguishing different data with the same underlying representation (August 23, 2010)
Day in the life of a Galois intern (August 20, 2010)
Type kata: Controlled sharing of references (August 18, 2010)
What high school Algebra quizzes and NP-complete problems have in common (August 16, 2010)
Generalizing APIs (August 13, 2010)
A radical Hackage social experiment (August 11, 2010)
Paper Monday (August 9, 2010)
The Gateway Drug to Type Programming (August 6, 2010)
Tour of a distributed Erlang application (August 5, 2010)
Buffered streams and iteratees (August 4, 2010)
How to pick your string library in Haskell (August 2, 2010)
Suggestion box (July 30, 2010)
Delaying implicit parameter binding (July 28, 2010)
Reader monad and implicit parameters (July 26, 2010)
Managing foreign pointers effectively (July 23, 2010)
Pipelines and continuations (July 21, 2010)
System.Posix.Redirect (July 19, 2010)
Maximum matching deadlock solution (July 16, 2010)
Flipping arrows in coBurger King (July 14, 2010)
Graphs not grids: How caches are corrupting young algorithms designers and how to fix it (July 12, 2010)
Safety first: FFI and threading (July 9, 2010)
Groom: human readable Show for Haskell (July 7, 2010)
Little’s law (July 5, 2010)
MVC and Purity (July 2, 2010)
Call and fun: marshalling redux (June 30, 2010)
Thinking about talk (June 28, 2010)
Marshalling with get and set (June 25, 2010)
First steps in c2hs (June 23, 2010)
The secret to successful autogenerated docs (June 21, 2010)
Principles of FFI API design (June 18, 2010)
Well-founded recursion in Agda (June 16, 2010)
Setting up Cabal, the FFI and c2hs (June 14, 2010)
The Haskell Preprocessor Hierarchy (June 11, 2010)
Static Analysis for everyday (not-PhD) man (June 9, 2010)
AP Physics: Stuck in the concrete (June 7, 2010)
Databases are categories (June 4, 2010)
Bug boogie: Git and symlinks (June 2, 2010)
Punt the Prelude (May 31, 2010)
Use The Monoid: A worked example (May 28, 2010)
Bananas, Lenses, Envelopes and Barbed Wire
A Translation Guide (May 26, 2010)
Lazy exceptions and IO (May 24, 2010)
Upgrading to Ubuntu Lucid (May 21, 2010)
Class Reflections (May 19, 2010)
I Hate Patches:
Confessions of an Open-Source Developer (May 17, 2010)
Spring 2010: A Random Walk (May 14, 2010)
Refactoring Haskell code? (May 12, 2010)
Nested Data Parallelism versus Creative Catamorphisms (May 10, 2010)
Omnipresent Cabal (May 7, 2010)
Name conflicts on Hackage (May 5, 2010)
Design Patterns in Haskell (May 3, 2010)
Art. Code. Math. (And mit-scheme) (April 30, 2010)
Inessential guide to fclabels (April 28, 2010)
The Problem with xUnit (April 26, 2010)
Creative catamorphisms (April 23, 2010)
Association maps in mit-scheme (April 21, 2010)
Thoughts on discussion (April 19, 2010)
Dudamel visits MIT (April 16, 2010)
Inessential Guide to data-accessor (April 14, 2010)
Later Impressions of the VX-8R (April 12, 2010)
Diagramming in Xournal and Gimp (April 9, 2010)
You could have invented zippers (April 7, 2010)
Cup of FP with a Java twist (April 5, 2010)
Summer internship at Galois (April 2, 2010)
More fun with Futamura projections (March 31, 2010)
The case of the Hash Array Mapped Trie (March 29, 2010)
Ad hoc wireless (March 24, 2010)
Hunting for abstractions in mathematics (March 22, 2010)
Mutation sleuthing in Python (March 19, 2010)
Haskell, The Hard Sell (March 17, 2010)
Straitjacket programming (March 15, 2010)
Five tips for maintainable shell scripts (March 12, 2010)
Replacing small C programs with Haskell (March 10, 2010)
Being an expert considered harmful (March 8, 2010)
How to use Vim’s textwidth like a pro (March 5, 2010)
Third-party unattended upgrades in three steps (March 3, 2010)
Writing generator friendly code (March 1, 2010)
History as documentation (February 26, 2010)
The Art of Posing a Problem (February 24, 2010)
Comonads and Convolutions (February 22, 2010)
Type manipulation: Tricks of the trade (February 19, 2010)
Why we stay up late (February 17, 2010)
Hunting for constraints (February 15, 2010)
Scheming environments (February 12, 2010)
Sources of music (February 10, 2010)
Nested loops and exceptions (Oleg Kiselyov) (February 8, 2010)
Nested loops and continuations (February 5, 2010)
Classes begin (February 3, 2010)
Cute macro tricks in the kernel (February 1, 2010)
Workflows in Git: Single-user style (January 29, 2010)
Arcadia Rising posters (January 27, 2010)
To the right! Autocompletable names (January 25, 2010)
Hacking git-rerere (January 22, 2010)
Too many leftovers! (January 20, 2010)
Five advanced Git merge techniques (January 18, 2010)
Typeclasses matter (January 15, 2010)
Sup: Mail for Nerds (January 13, 2010)
First impressions of the VX-8R (January 11, 2010)
Why Haskell? The big question (January 8, 2010)
rxvt-unicode for gnome-terminal refugees (January 6, 2010)
Audio connectors and radios (January 4, 2010)
Adventures in Three Monads (January 1, 2010)
2010: A Roadmap (December 31, 2009)
Iron Blogger (December 28, 2009)

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