jeffcarp

A Debugging Journey into XLA, TPUs, and JAX

Mon, 23 Feb 2026 00:00:00 +0000

I published an account of an interesting* yak shaving journey I went on to debug a custom Pallas kernel on TPU. I’ll probably inline the content here at some point.

*Maybe to me and two other people on Earth

Helpful Mindset Shifts for GPU Users Looking at TPUs

Thu, 29 Jan 2026 00:00:00 +0000

Disclaimer: The views and opinions expressed in this post are my own and do not necessarily reflect the official policy or position of my employer.

As someone who’s worked with TPUs for a while, I’ve seen a common pattern in people coming from the GPU world: they’ll take a look at a TPU chip’s specs, then look at a comparable GPU, and see numbers for the GPU chip that are obviously higher and scratch their head. Let’s look at TPU v5p (the training-optimized chip released in 2023) compared to the Nvidia H200 (the flagship AI GPU also released in 2023):

Thoughts on Helix

Mon, 12 Jan 2026 00:00:00 +0000

I’ve been a die-hard vim user for 12 years. But recently, inspired by posts from Julia Evans and Felix Knorr, I have been trying out Helix–a relatively new terminal-based editor written in Rust–and I’ve been pleasantly surprised by the experience.

Things I like

It’s snappy! Even though some of the command flows have changed, I can still get around the editor using my old vim muscle memory.

Initial Thoughts on Obsidian

Sun, 21 Dec 2025 00:00:00 +0000

Over the years I’ve used a variety of different note taking apps and systems:

2008: During college I took mainly handwritten notes. I used Apple Notes for casual snippets
2012: Mostly kept Markdown notes in a directory
2016: Switched from iOS to Android and used Google Keep for notes
2020: Moved to Notion
2022-present: I’ve been using Apple Notes as my primary note taking platform.

This year, based on a tip from a coworker, I started checking out Obsidian and trialing it for taking notes, writing, and planning various things. I’ve been enjoying it so far – it feels like building my own personal Wikipedia. Here are some additional thoughts.

Notes from Adaline Applied at AGI House

Wed, 11 Jun 2025 00:00:00 +0000

Last week I attended an AI product summit at the beautiful AGI House on the peninsula. It was a fun day getting exposed to what’s going on the frontier of product and AI. Here are my semi-structured notes.

The thorniest issue in tool use is identity and authentication
- Authentication bugs are much worse with agents because they can move faster (e.g. in 15 minutes an agent can exfiltrate a lot more data than a human).
Memory for LLMS will become more critical. MCP-based memory will enable portability across providers.
Tool descriptions are important, treat them like system prompts. An example of a great tool description is sequential thinking
Current models fall apart above 5 loaded tools
Current pattern is to delegate tasks to a sub-agent that’s very well tested against the specific inputs/outputs
MoE points to further specialization in agent space
“I’d rather have an agent that does one thing very well.”
“Tiny teams”
- Can you have super leverage by harnessing a fleet of agents?
Anthropic’s research into how long can a model complete a task correctly? Currently O(mins) - next step O(10s of mins)
Proactive agents (I thought this was super compelling)
- Background thread monitoring your life, chimes in when it can be useful.
There are two types of challenges in AI product right now: ones that will become solved as ai gets smarter, and those that will stay hard
Meme: every tool came from the abuse of context
Different software prioritizes different things, like being able to iterate quickly, or better reasoning around the whole system
Focus on where the handoff points are between humans and AI
OpenAI is about to launch a platform with value exchange, same as FB did with their dev platform, which they opened up then two years later rolled back and slurped up the popular use cases into their platform - Brian Balfour
- The game is to join it, get the distribution, then get off it and take your users with you ASAP
Brand is associated with a person at the company having an opinion in public in a specific space
- So: be out there and be visible in voicing your opinions as a thought leader and maybe iconoclast in a space
- It helps customers narrow down if their personality matches the brand
Communication is lossy - holding the entire product in one persons head is super valuable
User complaints don’t necessarily mean they’re switching
- Focus on what is the users “hell yes” case study
VCs are starting to focus on “quality of revenue”
You can build a moat with your good taste
- Being opinionated is a plus for founders

Cool tools mentioned

https://opentools.com
https://modelcontextprotocol.io/
https://www.ragie.ai/
Poe for ‘subscription fatigue’ :)
https://thesephist.com/posts/tools/
https://corecursive.com/024-software-as-a-reflection-of-values-with-bryan-cantrill/
https://www.granola.ai
https://decagon.ai/product/overview

Best Articles of 2025

Fri, 25 Apr 2025 00:00:00 +0000

This is an ongoing list of the best articles I’ve read this year.

Tensor Parallelism with jax.pjit - a super intuitive explanation of tensor parallelism
The Annotated Transformer
Attention From First Principles
Ten Rules for Negotiating a Job Offer
Note to my present self
Video: I’m Politely Begging You to Write Nonfiction
21 Facts About Throwing Good Parties
Tiny TPU
Heavyweight: An Art Project About Lawyer Vibes

How to Fake Multiple CPUs in JAX

Thu, 13 Mar 2025 00:00:00 +0000

Here’s how to emulate multiple CPUs when running JAX. This makes it easy to test multi-TPU/GPU code without actually needing the accelerators.

import os
os.environ['XLA_FLAGS'] = (
    os.environ.get('XLA_FLAGS', '') +
    " --xla_force_host_platform_device_count=8"
)

import jax
jax.devices()

[CpuDevice(id=0),
 CpuDevice(id=1),
 CpuDevice(id=2),
 CpuDevice(id=3),
 CpuDevice(id=4),
 CpuDevice(id=5),
 CpuDevice(id=6),
 CpuDevice(id=7)]

Reflections on Becoming a Manager

Fri, 31 Jan 2025 00:00:00 +0000

Last year after rejoining Google, I became a manager for the first time. As a long-time IC, I had some preconceived beliefs about what the job would be like, many of which were wrong.

During this transition a mentor pointed out one chapter from Nine Lies about Work about how humans are terrible at objectively rating other’s behavior. The result is that your entire work life is filtered through the lens of your manager’s point of view. I think this is something anyone with a boss has experienced: a great one can make your life amazing, and a bad or nonexistent one can make it a living nightmare. The saying “you don’t leave a job, you leave a manager” has rung especially true in my journey.

Doing Post-Quantum Cryptography in JAX

Sun, 05 Jan 2025 00:00:00 +0000

In 2018 while studying ML and cryptography around the same time, I realized that many cryptographic algorithms can be expressed as computation graphs, the same ones supported by major ML frameworks, which led to a completely frivolous attempt to implement cryptographic algorithms in TensorFlow, just to see if it would work.

The world has changed a lot since 2018. JAX is growing in popularity as an ML framework, and in the cryptography space, post-quantum cryptography has gone from a mostly theoretical threat to a slightly more real one. So continuing the motivation of the original post, I decided to look into implementing a post-quantum cryptography algorithm in JAX.

2024 Year in Review

Wed, 25 Dec 2024 00:00:00 +0000

Keeping it short and sweet this year. Here are my highlights:

Welcomed a baby into the world!!!
Recovered enough to run again
Ran 138.5 miles
Left Waymo and Joined Google
Became a manager
Was mentioned in TechCrunch
Went to Hawaii for our babymoon
Went to Taiwan and China to visit in-laws and got to pick tea on a tea farm
Read 21 books
Took 104 Waymos
Drank 45 drinks (exactly the same as last year)

How I’m Learning JAX

Fri, 13 Dec 2024 00:00:00 +0000

Recently I’ve been trying to learn more about JAX, the next-gen ML framework from DeepMind. These are the resources I’ve found most helpful so far.

The JAX docs, which are excellent
Patrick Kidger’s Learning JAX as a PyTorch developer
JAX AI Stack tutorials
The book JAX in Action, along with accompanying Python notebooks
Codebases: Gemma, MaxText
How to Scale Your Model

If you know any more good pointers please let me know.

Best Posts I Read this Year

Mon, 02 Dec 2024 00:00:00 +0000

Here’s a list of articles from this year that resonated with me.

Trail Running Bucket List

Sun, 01 Dec 2024 00:00:00 +0000

A while back I put together a personal “top 10” list of trail runs I want to complete in my lifetime. In terms of running goals, I find myself drawn less to the big races and time goals, and more to the thing that makes me want to get out the door and run in the first place: running in beautiful places and taking on technical and logistical challenges. This is my list as it currently stands. I plan to keep this updated and write more about my journey here.

Favorite Technical Books

Fri, 29 Nov 2024 00:00:00 +0000

Here’s a quick list of my favorite software engineering books I’ve read over the years. I plan to keep this list updated as I discover (or am recommended, hint hint) more.

Crypto: How the Code Rebels Beat the Government—Saving Privacy in the Digital Age, Levy
Cryptography Engineering: Design Principles and Practical Applications, Ferguson, Schneier, Kohno
Designing Data-Intensive Applications, Kleppmann
Designing Machine Learning Systems, Huyen
Reinforcement Learning, Winder
Hands-On Machine Learning with Scikit-Learn and TensorFlow, Geron
Site Reliability Engineering, Beyer, Jones, Petoff, Murphy
Linux Kernel Development, Love

Reflecting on this Blog

Wed, 20 Nov 2024 00:00:00 +0000

I wanted to take a second to reflect on the tone and content of this blog, which overall I’m not super satisfied with. This blog has primarily served as a place where I put mostly software engineering and running content over the years. However, rarely do I compose a post for this blog that I feel is “good enough” to be publishing here.

This goes beyond perfectionism — I think seeing amazing content every day on aggregation websites like Reddit and “the orange website” creates this implicit feeling that every post I produce needs to be well-written, technically impressive, and cast me in a good light. For better or worse, having my name as the title of this blog makes me feel like every post has a material effect on my (vomits in mouth a little bit) personal brand.

Quickly saying “no” to ideas is harmful

Mon, 23 Sep 2024 00:00:00 +0000

I’ve observed during my software engineering career the different reactions senior engineers have when new ideas are brought up.

Sometimes when an idea is presented, usually by a junior engineer, a senior engineer will chime in very quickly to emphatically describe why it won’t work. I think this is very harmful to team culture for a couple reasons.

First, it reinforces the bias toward authority for senior engineers. When any engineer brings up an idea, even if it’s overall a bad idea, there is always a nugget of truth – they observed a real issue and offered a real solution. Immediately shooting down ideas discards this truth.

I Joined Google (again)

Thu, 18 Jul 2024 00:00:00 +0000

Joining Google in 2016 vs. 2024.

This Spring I joined Google for the second time. I’m working on core ML infrastructure, specifically ML frameworks for Keras, JAX, and Gemini.

Not everyone is aware that Waymo is a completely separate sister company to Google. Going between the companies is an external hire in both directions.

Since joining Waymo four years ago, I worked with a ton of excellent people on a lot of different aspects of ML infra, including quantization-aware training, ML training frameworks, and global-scale automation of TPU training and simulation pipelines. It was always super rewarding walking around the streets of SF encountering a Waymo doing a specific behavior and thinking to myself “I worked on that model!!” (at least in very small part 🙂)

Engineering Management for the Rest of Us reading notes

Sat, 24 Feb 2024 00:00:00 +0000

I really enjoyed this book. Here are some of the biggest takeaways for me.

As a manager, your work is meetings. That means not protecting your calendar as much. People come before focus blocks. Corollary: making sure you can perform at a high level in meetings; meaning exercising in the morning or doing what it takes to make you the happiest and best person in meetings.

The importance of keeping a gratitude journal. Seeing the good in things makes you see the good in more things.

Deciding between a static and dynamic site

Thu, 04 Jan 2024 00:00:00 +0000

Hi, I’m trying to blog more this year. Maybe not every day, but more frequently.

In a recent post I mentioned I’ve been working on a fast frontend for a Chinese-English dictionary. In the spirit of “blog about what you’ve struggled with”, the biggest challenge I’m currently facing is choosing between designing the site as front-end heavy or back-end heavy.

I’ve written two initial versions of the site: one as a fully static website and one as a fully backend app in Go. Despite the server-side version being written in Go, I’m not super happy with the load time of the app. Even when the server is warmed up, the initial document load time is 30-40ms, whereas the static site is 10-20ms.

2023 Year in Review

Mon, 25 Dec 2023 00:00:00 +0000

Hi there, it’s time to reflect on what I was up to this year.

Running

I started 2023 thinking I had a long-term knee injury. Around Summertime I made a breakthrough in discovering it wasn’t a knee issue but a toe issue. Since then I’ve been keeping the mileage low and trying to build a healthy base.

In total I ran 361 miles this year, which is down from usual but I was very consistent in my training. I was super grateful to have the consistency and support from my running buddies at WeRunSF and Noe Run Club.

Considering File Formats for ChineseDict

Tue, 05 Dec 2023 00:00:00 +0000

Recently I’ve been hacking on ChineseDict, a fast web frontend to look up Chinese words. I started the project originally to fulfill a specific use case: when practicing chatting with friends or watching a video, I need search results in milliseconds, not seconds.

The website uses the CC-EDICT dictionary to power the results. I now want to expand each term with examples and extra data in a way that’s easy to store on disk and update via git commit.

Rules to Live By

Fri, 24 Nov 2023 00:00:00 +0000

John Cage’s 10 rules for students and teachers

Kevin Kelly - 103 Bits of Advice I Wish I Had Known

Kevin Kelly - 68 Bits of Unsolicited Advice

Dru Riley - 100 Rules To Live By

Khe Hy - 43 life lessons at age 43

Octaphilosophy: The Eight Elements of Restaurant André

Thelonious Monk’s 25 Tips for Musicians

Ideopunk - 100 Tips for a Better Life

Russ Roberts - My Twelve Rules for Life

2022 Year in Review

Thu, 29 Dec 2022 00:00:00 +0000

Hi friends,

Like last year, here’s a brief overview of what I got up to in 2022.

Running

Despite this being my biggest running year in terms of mileage (683mi), I struggled with injuries pretty much the whole year, likely due to too much racing and not enough training.

My “goal race” for this year was running the Four Pass Loop, a 28mi loop with 9000ft of vert around the Maroon Bells in Colorado and rated the #1 trail run in the country on Trail Run Project. I made it about halfway before turning around, due to running the Double Dipsea two weeks before and not giving myself enough time to recover.

Recent Running Lessons

Tue, 13 Dec 2022 00:00:00 +0000

When I have a running injury, it’s not always the right thing to completely stop running and wait for it to heal.

Sometimes it’s worse to stop running altogether, because while the injury is healing, all the surrounding muscles are getting weaker. This actually makes injury more likely when I return to running. My current strategy is to keep running as much as possible as long as the pain is less than 3/10.

Questions I Ask Companies in Interviews

Sun, 22 May 2022 00:00:00 +0000

Inspired by Julia Evans’s post Questions I’m asking in interviews and Chip Huyen’s Questions to ask your interviewers section from her ML Interviews book, here are the questions I ask in interviews, targeting staff roles in ML infrastructure.

Overview

My general approach is:

Have 3-5 “primary” questions that cover the most important things.
Have a backlog of 20 questions that I can fire off as necessary. I never want to run out of questions or repeat a question in an interview.
Only ask “hard questions” after getting a job offer.

Primary Questions

What kind of scope and responsibility can I expect to have?
What are the biggest challenges you’re facing right now?
How does this team fit into the broader organization?
How big is the team and how fast is it growing?

Backup Questions

Recruiter-focused questions
- What rubrics will I be evaluated on?
- What kinds of questions should I be prepared for?
Team Alignment
- How fast are you growing and how is headcount allocated between teams?
- Who is competing for scope with your team (internal and external)?
- How many headcount do you have open right now?
Career
- When does the career ladder split between IC and management? What does that transition look like? How often do opportunities at that level come about?
- How easy is it to change teams at the company if things don’t work out?
Enjoyment
- What are the working hours like? When do most people work?
- What does your day look like?
- What do you like about working on this team? At this company?
Technology
- What’s your tech stack like?
- Do you have an oncall rotation and what is it like?
- Do you standardize tech across teams?
- What is your process for big projects? Do you write design docs? Do you have design reviews?
- How much tech debt do you have?
- How are tech teams organized? By technology or by product?
- What is the release cadence?
Leadership
- What is your decision making process?
- What are you looking for in employees and leaders?
- Who is the ultimate decision maker?

Kuli'ou'ou Ridge Loop Trail

Sat, 12 Mar 2022 00:00:00 +0000

View from the second peak.

While on vacation in Hawaii I was super pumped to get in a nice trail run. Here’s how it went.

Course


Distance	5.3 miles
Elevation gain	2326 ft
Average grade	12%(!)
Duration	2:32:43
Temperature	75F
Humidity	87%
Strava	Link
AllTrails	Link

Viewed on Google Earth.

Elevation profile.

Loadout

Nutrition requirements

Favorite Books of 2021

Sat, 01 Jan 2022 00:00:00 +0000

Happy new year! Here are my 5 favorite books of 2021.

Empire of Pain

A sprawling, enthralling story of the opiate epidemic told through the lens of multiple generations of the family that ushered it in. This book reminded me of Bad Blood, but with far larger scope.

In his book Opium: A History, Martin Booth observes that when it comes to products derived from the opium poppy, “history repeats itself.” During the American Civil War, morphine was widely embraced as a salve for terrible battlefield injuries, but it produced a generation of veterans who came home after the war addicted to the drug.

2021 Year in Review

Sat, 25 Dec 2021 00:00:00 +0000

I wasn’t initially planning on writing a year in review blog post for 2021, but I was recently reminded of how nice it is to have a concise public record of the things that were important to me for each year (even if nobody other than me reads it). So here it goes!

Highlights

Getting vaccinated!
Going back out to restaurants and dining
Attending weddings of my two of my best college friends
First Waymo SF ride
Traveling again
Wednesday morning trail runs

Recruiter Autoreply Bot 2

Mon, 22 Nov 2021 00:00:00 +0000

Let me state the obvious: recruiters aren’t actually sending most recruiter emails. They automate it with software. However, the recipients of recruiter emails must spend real human time either responding to or ignoring these emails. Unfortunately just ignoring the emails triggers more followup emails (they usually come in sets of 3). This adds up to a lot of wasted time.

Background

Back in 2019 I created a bot that automatically responded to recruiters I tag with a certain label in Gmail. The way the bot works is:

Things I Wish I Had Known About Earlier

Sat, 20 Nov 2021 21:02:53 -0800

Anki and Spaced Repetition

I’ve adopted the Anki app to help learn new vocabulary and retain various things I learn Currently my decks are:

My Anki decks

Spaced repetition flashcards are great. I would have done much better in school if I had known about them.

Investing and Indexing

For most of my 20s I didn’t know much about investing, so I avoided it. Better to not risk my money, is what I thought. Turns out holding cash is also risky. I wish I had known about index funds earlier — the book that taught me the most on the subject is Jack Bogle’s The Little Book of Common Sense Investing.

2020 Year in Review

Sun, 27 Dec 2020 00:00:00 +0000

2020. What can I say? It was a year I don’t think any of us need to live again. Here’s a brief overview of my year.

Highlights

In February on Valentine’s day, Elva and I adopted Noona(!), an 8 year old Siberian Husky. She’s the chillest, sweetest dog. Due to lockdown starting 2 weeks later, I’m sure she thinks that spending all day at the house giving her attention is normal.

How to clone a Google Source Repository in Working Copy iOS

Sat, 19 Dec 2020 02:00:00 -0700

I recently went through this process and couldn’t find a guide (though I swear one existed at some point in the past). Here’s how to clone a git repository from Google Source Repositories in the Working Copy iOS or iPadOS app:

Navigate to https://source.cloud.google.com/
Pick out the repo you want to clone and open the clone dialog (it looks like a “+” icon)
Go to the “Manually generated credentials” tab
Click on “Generate and store your Git credentials”
Go through the authentication flow
You should be prompted to copy a shell command onto your clipboard
Go to the Working Copy iOS app
Go to Settings (the gear icon) > Authentication Cookies
Tap the “+” icon and import from clipboard
You should now be able to clone the repository using the https://source.developers.google.com/p/... URL

Hope that helps if you’re in the same boat.

Grace Hopper 2019 Trip Report

Sun, 16 Aug 2020 00:00:00 +0000

Despite this trip report being over 9 months late, I wanted to share it because I can’t stop thinking about how positive an experience this conference was. Grace Hopper is the largest women in tech conference in the world, with around 25,000 attendees flying into Orlando, FL from all parts of the world for the 2019 conference. In previous years I had been interested in attending but hadn’t gotten the chance—and I (as a man) also strongly did not want to take the spot of a potential woman visiting the conference. This year I was lucky to get the chance to attend and thought it would be a valuable experience to learn how to be a better ally and advance the cause of women in tech, as well as learn about the latest tech from across the industry.

用20行Python构建Markov Chain语句生成器

Sat, 04 Jul 2020 10:44:41 -0800

A bot who can write a long letter with ease, cannot write ill.

—Jane Austen, Pride and Prejudice

这篇文章将引导您逐步学习如何使用Python从头开始编写马尔可夫链(Markov Chain)，以生成好像一个真实的人写的英语的全新句子。简·奥斯丁的《傲慢与偏见》(Pride and Prejudice by Jane Austen) 是我们用来构建马尔可夫链的文字。 Colab 上有一篇可运行的笔记本版本。

Read the English version of this post here.

Setup

首先下载“傲慢与偏见”的全文。

# 下载Pride and Prejudice和并切断头.
!curl https://www.gutenberg.org/files/1342/1342-0.txt | tail -n+32 > /content/pride-and-prejudice.txt

# 预览文件.
!head -n 10 /content/pride-and-prejudice.txt

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  707k  100  707k    0     0  1132k      0 --:--:-- --:--:-- --:--:-- 1130k
PRIDE AND PREJUDICE

By Jane Austen



Chapter 1


It is a truth universally acknowledged, that a single man in possession

添加一些必要的导入。

The Most Commonly Used Chinese Words

Sun, 15 Mar 2020 15:23:36 -0700

I think the most effective way to learn a language is to prioritize learning the day-to-day most frequently used words. Picking words to study in order of frequency is the optimal way to maximally increase your marginal understanding of the language for each successive word you learn.

To that end, I took a dataset of Weibo (China’s Twitter) posts and ranked all words that appeared in the dataset order of frequency.

Napa Half Race Report

Wed, 11 Mar 2020 08:24:16 -0800

center-384

The end of the pain cave. Note: the clock time in the picture is for a different race.

I PR’d my half marathon at the Napa Half!! Yeahh!!!!

Old PR: 1:31:37 at the 2019 Kaiser SF Half.
New PR: 1:28:59 (link).
Improvement: 2.9% (-2:38)

In this post I want to look into the race and more closely analyze what went well, what could have gone better, and what was interesting about this race.

jeffcarp CV

Fri, 03 Jan 2020 21:14:42 +0700

This is a “brag doc” to contain all my accomplishments in a more long-winded and media-rich format than my resume can handle.

Experience

Waymo

2019 to present — Mountain View, CA

Gained Python readability.
(More here later)

Google

2016 to 2019 – Mountain View, CA

Built and launched wpt.fyi
- Designed back-end, front-end, and data processing pipeline for promoting browser API interoperability.
bugs.chromium.org
- Designed and built burn-down charts for velocity tracking.

Hiring contributions

SWE interviewer – top 1% of interviewers at Google (by volume)
Hosted 1 intern and co-hosted 2 STEP interns.
Served on hiring committee.
Led SWE interview prep workshops for students at target universities (UCTP program)

Braintree / PayPal

2014 to 2016 – San Francisco, CA

Projects

Fri, 03 Jan 2020 21:14:42 +0700

ColbyBox (2012)

I turned an infrequently used LCD screen in a prominent location in our college’s student center into a Twitter live feed that also supported photos and videos.

The ColbyBox, an LCD in the student center.

2019 Year in Review

Tue, 31 Dec 2019 04:37:09 +0700

In 2019 I got married—twice! (to the same person!) I changed jobs. I ran my first marathon. 2019 was a huge year in my life.

I grew in a lot of ways this year. Wedding planning was a huge undertaking and strengthened our communication and quick decision making skills. Additionally this year I started working with a therapist which has been great—I’m wondering why I never thought of doing that earlier.

The Best Books I Read in 2019

Sat, 28 Dec 2019 11:11:11 +0800

Here are my 4 favorite books from 2019.

A British couple buys a farmhouse in the South of France and spends the next 12 months exploring the countryside, meeting the locals, renovating the house, and of course, eating and drinking well in [A Year In Provence](https://www.goodreads.com/book/show/ 40189.A_Year_in_Provence) by Peter Mayle. For a premise that could come off as a little posh, the detail in this story is so rich and the storytelling so genial I couldn’t put it down. I recommend having Google translate closeby.

CIM Race Report

Thu, 12 Dec 2019 20:32:54 -0800

I did it!! I ran my first marathon! It was painful… but worth it! Despite still being pretty sore I can tell you I would definitely do it again. Solid Type II fun.

My final time was 3:59:44, sneaking in just under 4 hours. You can view the full splits here and my run on Strava here.

Despite consciously trying to keep my pace under control in the first half, I went out too fast. My first half marathon was 1:50:59 vs. 2:08:45 for the second half—a positive split of 16%. 😕

Marathon Training Update

Thu, 21 Nov 2019 08:47:45 -0800

I’m signed up for the California International Marathon (a.k.a. CIM) in Sacramento, which is in less than 3 weeks! This will be my first marathon (the SF Marathon this year was supposed to be, but I gave myself a toe injury by overtraining).

My goal is simply to finish. I think having any sort of time-based goal would risk pushing me past the point of injury during the race.

Am I ready? Probably not 😄. My longest long run so far has been 15 miles. My weekly mileage is probably super low compared to most marathon training programs.

I'm Joining Waymo

Sun, 10 Nov 2019 15:38:38 -0800

Quick life update: I’ve left the Chrome team and joined Waymo (formerly the Google self-driving car project). I’ll be working on ML infrastructure.

It was a fantastic whirlwind 3 years working on infrastructure for Chromium and helping to–in a very small way–push the open web forward. On the team I launched wpt.fyi, a resource to help align the APIs of all browsers. I worked on syncing source code across repos. I launched a couple TensorFlow ML models. And I helped make the bug tracker quicker and more useful for everyone in the project.

Things I Learned as a First-Time Intern Host

Sat, 31 Aug 2019 11:13:25 -0700

I hosted an intern for the first time this summer. It was my first time being somebody’s manager and it became a huge learning experience for me as well as a really fun time. My intern worked on adding many features to velocity-tracking charts, rewriting our ML models in TensorFlow 2.0, and a few other projects.

Here are the biggest areas where I struggled as a host and the important lessons I took away from those experiences.

How are Words Represented in Machine Learning?

Sat, 13 Jul 2019 01:31:29 +0000

Note:This post had a good run, but it is now very out of date. Check out newer content around tokenizers for a more up-to-date view.

Machine learning on human languages is a super exciting space right now. Applications are exploding—just think of how many natural language ML models it takes to run a smart assistant, from transforming spoken audio to text, to finding the exact part of a web page that answers your question, to choosing the correct words with the correct grammar to reply to you.

3 Tips for New Technical Interviewers

Sat, 06 Jul 2019 15:00:31 -0700

One year ago I conducted my first software engineering interview at Google. In that first interview I gave, I guarantee you I was more nervous than the candidate I was interviewing. Those first few interviews were particularly nerve-wracking. A lot was on the line—I didn’t want to screw up this person’s career by being a bad interviewer!

Since then I’ve conducted a great deal more interviews and learned a lot about how to interview candidates successfully. I want to share three small tips that would have helped me improve as I was getting started.

On Being Injured (Again)

Fri, 14 Jun 2019 14:55:14 -0700

tl;dr:

I signed up for the SF Marathon (this would have been my first marathon), then overtrained, got injured, and am currently recovering. I’m probably going to defer my registration to 2020 and become a cheering squad this year.

(╯°□°)╯︵ ┻━┻

This is a cycle I’ve been through over and over again. I literally wrote about this in 2015. Being injured massively sucks. I can’t exercise the way I usually do, and I don’t get see my running buddies.

Setting Up a Recruiter Auto-reply Bot

Wed, 05 Jun 2019 13:16:00 -0700

If you’re a software engineer, you’re likely familiar with unsolicited emails from recruiters. Most are probably template emails. Some of them are funny, some are thoughtful, and some of them ask you to move 3000 miles, take a 50% pay cut, and code in a language you don’t know.

Impact

Recruiter emails have a measurable impact on productivity. If I were to hand-write a response to each one (taking 2 minutes), and I got 1 recruiter email a day, that’s 12 hours of work, or more than one full work day of each year… gone.

Measuring My Chinese Progress

Sat, 27 Apr 2019 22:20:24 -0700

Last summer I started learning Mandarin Chinese. To start I began taking classes at a Chinese language school in SF. For more practice I started an Instagram @jeffcarp_zh and tried writing a couple blog posts.

Almost a year later, I’m still going to Chinese class on a semi-regular basis (1 hour a week except when I’m taking a break) and keep up a daily spaced-repetition flashcard habit using the Pleco Chinese dictionary app (usually on the train into work).

Kaiser SF Half Race Report

Wed, 06 Feb 2019 13:46:20 -0800

Overall

It went great, I PR’d by 10 minutes! The course is super fast and the light drizzle of rain didn’t really put a damper on things.

Report

t-0:20

I arrived and was able to use the bathroom – they did a great job of making sure there were enough port-a-potties. After that since it was drizzling I hid under a tree to the side of the start line with a bunch of other runners who looked like they were from a club and knew what they were doing.

Building a Running Pace Calculator With AMP

Sun, 03 Feb 2019 23:45:38 +0000

Sometimes you need to know how fast you need to run to achieve a personal best time. Previously the way I did this was to search “running pace calculator” and follow and use one of the top results. However, I was doing this almost always on mobile and none of those results are very mobile friendly. There might be good native apps for this, but I’m a fan of the web and don’t want to download an extra app if I can avoid it.

How I Host Static Sites With Automatic Deploy on Green

Sun, 03 Feb 2019 23:19:44 +0000

This site, jeffcarp.com, is written in markdown and uses the Hugo static site generator. This post walks you through how I set automatic building, testing, and deployment to Firebase hosting.

Project Setup

I assume we’re starting from a working Hugo project. For more on how to set that up, see the Hugo docs.

Testing Setup

I want the site to be Deploy-on-Green (i.e. only if it passes the tests). The CI setup I use is GCP Cloud Build. I develop and debug these tests locally using the local-cloud-build command documented here. The steps I want are:

A Year of the Pomodoro Technique

Tue, 29 Jan 2019 15:19:10 -0800

The Pomodoro Technique is method for improving productivity by segmenting work into 25-minute intervals. You focus intensely on a task for 25 minutes, then take a break. Rinse, repeat.

I began using the technique to study for the cryptography course I took last winter. The benefits were clear from the beginning. I enjoyed working in 25-minute segments and started using it at work as well. I want to share with you some of the things I learned along this year-long journey.

Inspired

Sat, 19 Jan 2019 17:07:11 -0800

Inspired is a great introduction on how to be a Product Manager by Marty Cagan, a former engineer turned product expert. Here’s one of my favorite themes of the book:

Product: build the right product
Engineering: build the product right

Here are the most poignant things I learned from this book organized by category.

Product team structure

It’s important to have somebody between product marketing and engineering (i.e. the product manager). Otherwise UX gets skipped and the TL has to figure out what to build, which is a bad recipe for product-market fit.
Also a bad idea is to let sales direct engineering, if you do that you get features, not products.
Most product orgs are basically feature factories… don’t be like that.

Engineering management

Run product management and design in parallel with engineering - the PM and designers should always be 1-2 sprints ahead of eng.
To combat tech debt, give the engineering team “headroom,” i.e. 20% of resources to do with it what they want.

The importance of prototypes

It’s really important to take an engineer or two and create usable prototypes during the discovery phase. Otherwise most startups use their entire eng process and release cycle to ship experiments in order for product to iterate. This is why it takes 1.5-2 years for most companies to find traction, and why many startups fail
Cagan argues that making a full mock with all intended functionality not only is preferrable, but will actually let you ship faster by reducing risk later in engineering.

General product management

Software projects have two stages: Discovery (build the right product) and Execution (build the product right). After the discovery phase ends, the product spec needs to be locked down otherwise changes create “churn.”
Don’t rely on your manager as a mentor, it’s not their job.
To prevent surprises and make sure meetings with lots of high level stakeholders run smoothly, reach out to them beforehand to get them on board.

I thought this book had some fresh things to say about confidence. Frequently confidence is looked upon negatively in tech—something that MBAs who don’t know what they’re talking about have. But I really liked Cagan’s take on it:

Build a Markov Chain Sentence Generator in 20 lines of Python

Wed, 16 Jan 2019 10:44:41 -0800

A bot who can write a long letter with ease, cannot write ill.

—Jane Austen, Pride and Prejudice

This post walks you through how to write a Markov Chain from scratch with Python in order to generate completely new sentences that resemble English.

The text we’ll be using to build the Markov Chain is Pride and Prejudice by Jane Austen. You can follow along here or grab a runnable notebook version of this post on Colab.

2018 Year in Review

Mon, 24 Dec 2018 15:39:13 -0700

For the past few years I’ve been summing up my yearly highlights in a blog post. It doesn’t matter if anyone reads these posts—it’s nice to have these to be able to look back on the big things that happened in my life each year.

So without further ado, here’s an overview of the big things that happened in my life in 2018, from Running, to Reading, Learning Work, and Health, finally looking at how I did on my 2018 goals and setting 2019 goals.

Mindset: The New Psychology of Success

Mon, 10 Dec 2018 15:38:56 -0800

This book is about two ways of thinking: the fixed mindset and the growth mindset. In the fixed mindset you’re a finished product. Expending any extra effort is unthinkable because supposedly you’re already perfect. Then there’s the growth mindset, which tells us the only way you learn is from mistakes, talent doesn’t get you very far, and the people who succeed are the ones who work the hardest.

How to Solve Every Software Engineering Interview Question

Tue, 20 Nov 2018 22:13:48 +0000

The Googleplex at dusk

This post unfortunately does not contain a secret skeleton key that will unlock every tricky Software Engineering interview question. What’s below is a framework that you can apply to every interview question that will set you up for success every time.

Software engineering interviews are not primarily about seeing if you can pull the #1 most perfect solution to a problem out of your hat. What’s more important is showing your work: demonstrating your analytical skills and problem solving ability. This is where a framework is useful.

The Manager's Path

Wed, 14 Nov 2018 15:32:22 -0800

I can’t recommend The Manager’s Path by Camille Fournier highly enough for Software Engineers. I found this book super useful for understanding the structure of technical organizations. It contains tons of gems that I want to write on sticky notes and post above my desk at work, like:

Especially as you become more senior, remember that your manager expects you to bring solutions, not problems.

More Similar Mandarin Words

Sat, 20 Oct 2018 01:24:10 +0000

大家好，今天我要写一下更多相似的中文话。我的上次的blog post是英文写的 Similar Mandarin Words。下面是更同类的单词我遇到了在学中文。

“去” 和 “走”

都可以用去某处。“走”的意思是physically walk somewhere。去是more general。

“方才” 和 “刚才”

在词典方才和刚才都有同的意思。但是没有人说方才。人人用刚才。

“很有意思” 和 “很有趣”

都是同的意思。很有意思还有可能用sarcastically。

“见到”，“看到”, 或者 “看”，那个用？

看只是to see的意思。见到是看某人的意思。看到的意思是to notice。也可以是看某人的意思但是

再次谢谢Elva给教学我中文很好。

Reasons to Try Trail Running

Thu, 27 Sep 2018 18:44:49 +0000

No car exhaust fumes.
Works out different parts of your legs and core that wouldn’t otherwise be exercised on asphalt.
See wildlife.
Visit places and see sights where roads don’t go.
Races are more intimate and less anonymous. You make friends. Strangers encourage you along the trail. You encourage strangers.

It's OK to Make Mistakes in Coding Interviews

Tue, 25 Sep 2018 01:02:51 -0700

Imagine you’re an interviewer in a software engineering interview. The interviewee writes a method and it’s completely wrong. They go on to implement other parts of the problem, then later realize there’s a bug and come back and fix the original method.

One thing that isn’t super clear for both interview candidates and interviewers is how to treat mistakes like this. The candidate definitely made a mistake. But their final implementation is correct. Should they be penalized?

Sydney Photos

Thu, 26 Jul 2018 00:00:00 +0000

I travelled to Sydney in July to work with Chrome folks over there. Here are my pictures from the trip.

The Sydney Harbour Bridge

On Saturday I took the ferry to Manly Beach, a chill beach town up the coast from Sydney.

The view of the bridge and the opera house from the ferry.

The old escalators in one of the subway stations was repurposed into an art piece that hangs at the entrance.

Doing Cryptography in TensorFlow

Sat, 23 Jun 2018 13:00:14 -0700

On the left: the Feistel Network from the DES cipher, implemented below. On the right: a deep neural network.

TensorFlow is a popular machine learning framework. If you look under the hood, TensorFlow is a general platform for doing computation over tensors in the structure of a graph.

Some Similar Mandarin Words

Sat, 23 Jun 2018 01:02:51 -0700

This year I’m trying to start learning Mandarin Chinese. Here are some confusingly similar words I’ve come across.

认识 and 知道

The difference is between knowing a person, 认识 (rènshí) and knowing a fact, 知道 (zhīdào).

你认识她妈?	你知道我很酷吗？
nǐ rènshí tā mā	nǐ zhīdào wǒ hěn kù mā
Do you know her?	Do you know I'm cool?

正在 and 现在

Both roughly mean “now” but 正在 (zhèngzài) means currently or in general and 现在 (xiànzài) means literally right at this moment.

China Camp Trail Race Report: Things I Wish I Had Known

Sun, 03 Jun 2018 18:44:49 +0000

Yesterday I ran Inside Trail’s China Camp Trail Run, my first trail half. The course was good! The temperature was in the 80s but the course offered lots of shade. It was mostly single track trails with a few friendly mountain biker sightings. 1.5 miles into the race there was a nice steep 500ft climb.

As a beginner trail runner I want to share with you a few tips that I wish I had heard before the race.

Understanding the Security of Cryptographic Hash Functions

Mon, 16 Apr 2018 21:33:26 -0700

Hash functions are an extremely versatile tool that you can find nearly everywhere in software engineering.

Bitcoin mining is done by repeatedly computing SHA256 hashes.
git stores files internally using the SHA-1 hash of the content as the filename (content-based addressing).
When you download an app, your phone verifies that the app you’re about to run is the app you intended to download by computing a checksum (a hash of the entire app) and comparing it to one provided by the app store. If the values are different, that means someone might have changed the contents of the app.

This article intends to give you a deeper understanding of cryptographic hash functions, when to use them, and how to think about their security properties.

About

Sun, 01 Apr 2018 21:14:42 -0700

Hi, I'm Jeff Carpenter, a software engineer living in San Francisco.

I’m currently building frameworks for large-scale machine learning at Google. Prior to that I helped build out Waymo’s ML training and automation platform.

Outside of work I'm into running, books, and learning languages.

Elsewhere

These days I am most active on Threads: @jeffcarp
GitHub
LinkedIn
Substack

Best Of

Here are a few of my most read posts:

Current Side Projects

Open Source

I started wpt.fyi, a data platform+dashboard for making browsers more API compatible.
I’m the maintainer of abab, a JavaScript module for base64 with 8 million downloads weekly.
Various contributions to Chromium and Chromium infrastructure.
Various contributions to jsdom, a DOM emulation library for JavaScript.

Bookkeeping

The opinions expressed on this blog represent only my personal opinion and not that of my current or past employers.
Unless otherwise stated, all prose on this site is copyright under CC BY-NC-SA 4.0.
All code is copyright under the MIT License.

Things I Revisit Every so Often

Yishan Wong, Engineering Management
John Allspaw, On Being A Senior Engineer
Dr. Richard W. Hamming, You and Your Research

Random Stuff

Quotes
Playlists
- Songs to Read to
- Cabin Songs

Thoughts on Stanford's CS255 Intro to Cryptography

Sat, 31 Mar 2018 12:31:22 -0700

I’ve always been interested in Cryptography – the field is a really compelling marriage of beautiful mathematics with critical real-world applications. Much of the modern internet would not be possible without the clever math behind asymmetric encryption.

This Winter quarter I took Stanford CS255: Introduction to Cryptography. To be honest, it was quite challenging as I was still working full time as a software engineer on Chrome, and I was never that strong in the math department. However, I got a ton out of this course and solidly recommend it to anyone interested. The professor – Dan Boneh – was amazing and made the complex topics approachable. He publishes the textbook for the course for free here. Here are some interesting things I picked up from the course that I want to take with me.

New Blog, Who Dis?

Fri, 30 Mar 2018 13:10:14 -0700

I updated the design of my blog and moved it from jeff.is to www.jeffcarp.com. The site jeff.is is still available, but I’ll be moving over content shortly and setting up a redirect.

How to Export Evaluation Results in Tensorflow

Fri, 05 Jan 2018 21:33:26 -0700

2019 update: just a heads up, this post is about TensorFlow 1.x. For TensorFlow 2.x, you probably want to check out Keras custom callbacks.

In TensorFlow if you’re using a tf.estimator model, for instance tf.estimator.DNNLinearCombinedClassifier, and as part of your automated training infrastructure you want to save the evaluation results as a JSON file, it’s not super straightforward, so here’s how to do it.

Let’s say you define your EvalSpec like this:

eval_spec = tf.estimator.EvalSpec(eval_input_fn,
  steps=hparams.eval_steps,
  exporters=[exporter],
  name='eval')

You’ll need to write a new exporter class that will take the eval_result from your evaluation step and save it to a file using the GFile API.

Goodbye 2017, Hello 2018

Sun, 31 Dec 2017 21:33:26 -0700

Hi friends, here’s a quick overview of what I was up to this year.

The most important thing that happened this year

On a sunny day in August 2017, literally the smartest and most beautiful person I know and I embarked on a beautiful trail run on Mt. Tamalpais in Marin that ended on top of a mountain. Once we got to the summit, I asked her to marry me. She said yes!!!

Example: Save and Load a TensorFlow Model

Sun, 19 Nov 2017 19:07:30 +0000

2020 update: just a heads up, this post is about TensorFlow 1.x. For TensorFlow 2.x, you probably want to check out this guide .

This post details how to save and load a TensorFlow model using the DNNClassifier API.

The key idea here is that you define a function or a class beforehand that takes a model directory (in which it will save and restore the model parameters), adds that to RunConfig, and returns a tf.contrib.learn.Estimator, for example, tf.contrib.learn.DNNClassifier. See make_estimator for more details.

Chrome Security Architecture

Sun, 22 Oct 2017 19:07:30 +0000

While in Tokyo for BlinkOn8, a gathering for Blink and Chromium contributors, I gave a talk at a coding school about the security architecture of Chromium. Here are the slides.

I’m not an authority when it comes to security or specifically security in Chrome, but I’m really interested in it and I hope this deck has some information you find interesting as well.

Mt. Rainier Backpacking Trip

Mon, 27 Feb 2017 00:00:00 +0000

I went on a 7 day backpacking adventure around Mt. Rainier with two of my best buds. Here’s the video.

2016 Year in Review

Sat, 31 Dec 2016 15:39:13 -0700

2016 turned out to be a pretty crappy year, but it wasn’t all terrible. I made some good progress on my personal goals, so there’s that. Here’s a review of my 2016. If this sort of post strikes you as excessive navel gazing, that’s because it is — therefore I urge you to stop reading right now.

Work

The theme for this year of my life is probably “insane amounts of learning.” In the first half of 2016 I was at Braintree working on a new payments platform. In August I joined the Google Chrome team.

Where Web Payments are Going

Sun, 31 Jul 2016 15:15:40 +0000

I gave a talk at the SF Payments Engineers meetup about Web Payments. Here’s the blogified version of that talk. Check out the slides from my talk here.

Mobile checkouts are a terrible experience for customers. Both consumers and merchants are both feeling the pain. Mobile checkouts convert about 66% worse than desktop checkouts.

A slide from the PaymentRequest presentation at Google I/O 2016.

Part of the problem is that every company needs to build their own credit card form. Checkouts range from great UX to terrible UX, but the heterogeneity is what really makes it a pain for consumers.

You are an engineering manager whether you realize it or not

Mon, 25 Jul 2016 21:33:26 -0700

Over the past few months I’ve mentioned to friends that I want to learn engineering leadership skills. Each time the reaction is: “you want to get into management??” That’s not how I see it.

As engineers we hold the lone wolf in high regard, the hoodie-wearing coder hacking away in the corner at a genius project. But large projects that deliver a ton of value are made by teams of engineers, not lone wolves.

2015 in 5 Themes

Mon, 11 Jan 2016 21:39:13 -0700

Here are the 5 most defining themes of my 2015, in no particular order.

1. Scapula

I fractured my scapula (shoulder blade on my right side) on December 24, 2014 while skateboarding with my sister. I spent most of January 2015 resting and recovering. Part of that meant starting physical therapy.

PT was such a good influence on not just my scapula, but other parts of my life, that I consider breaking my scapula a highly net positive life event.

Breaking the Cycle

Sun, 29 Nov 2015 15:15:40 +0000

I’ve always been interested in running and looked up to friends who’ve trained for marathons or go running all the time. Running is great because it’s really easy to fit into a busy schedule and it leads me to explore new parts of my city (or better yet, a city I’m visiting).

Throughout my life, however, I haven’t been able to run much due to an ongoing series of injuries. In Middle School I absconded from the swim team for a semester to join the track team, but I didn’t end up running much due to excessive heel pain (maybe I was growing too fast). In college I ran on and off – I even racked up 13.3 miles on a training run once – but throughout college I had knee pain that kept me from training in any serious fashion.

Wrist Upgrade: Suunto Ambit3

Sun, 25 Oct 2015 00:00:00 +0000

I’m not a huge runner but whenever I run I use Strava for GPS tracking. I had been carrying my phone with me while I ran, but since it’s on the larger side and I can’t easily glance at it while I run, I looked into getting a watch with GPS + a heart rate monitor. After some research, I decided on the Suunto Ambit3.

Here are the things I like about it:

Reading Papers: Bufferbloat, SSL Warnings, Orleans, and more

Tue, 24 Mar 2015 00:00:00 +0000

Inspired by the article Should I read papers? by Michael R. Bernstein and the amazing Papers We Love GitHub repository, I set out at the beginning of January 2015 with the goal of reading 15 academic papers. In this post I want to share with you my notes for the 4 I loved the most.

Takeaways

In a certain way reading papers is a comforting activity. In a world where the front-end framework you’re using might be eclipsed in usefulness in 1 or 2 years, many of these papers present ideas that are as applicable today as they were 43 years ago. Here are the publish dates of the 15 papers I read:

Visualizing JavaScript Project Structure

Mon, 12 Jan 2015 00:00:00 +0000

Recently I thought to myself: fairly frequently I dive into a big JS codebase and need to poke around for a while to get acquainted with the project structure, wouldn’t it be nice if I could have a more visual way of seeing the whole thing to make sense of it all?

It was this need I was trying to fill when I embarked on my open dev project last Friday. In this post I’ll try to walk through the steps I took so you can replicate them. If you want to just to play with the final project, it’s available as an npm module named jsviz (npm: jsviz, GitHub: jeffcarp/jsviz).

How System Calls Work

Thu, 18 Sep 2014 16:36:39 +0000

Why should you care about syscalls?

As a web developer, learning about syscalls and the infrastructure around them can make you feel quite a bit more confident in debugging and reasoning about how systems will perform. Ruby and C++ both have their own idiomatic ways of opening files, but in the end they both end up using the syscall open(). This is because userland processes (like web applications) have only one way of communicating with the operating system: syscalls.

Weird and Cool things from Linux Kernel Development

Fri, 12 Sep 2014 00:06:15 -0700

Recently I picked up Linux Kernel Development by Robert Love since I like his posts on Quora. Here are the things that I thought were cool or just surprised me.

Threaded Trees

Are cool. They act both like trees and linked lists.

Child processes vs Threads

The only difference between a child process and a thread in Linux is whether the CLONE_VM flag was passed to clone(), which copies the parent’s address space which allows the child to access the parent’s memory.

Unforseen Perks of Pair Programming

Sun, 15 Jun 2014 19:03:46 +0000

As someone who had never pair programmed before, it was exciting to get thrown into the deep end during my first week at Braintree where engineers pair nearly 100% of the time.

The relative merits of pair programming have already been spoken about at length.^[1]^[2] This post is not an attempt to argue one way or another. Whether it works for any organization is probably too context-dependent for any axioms I could lay down.

Interviewing 2 Years in: What Worked

Fri, 06 Jun 2014 00:00:00 +0000

I’m almost pee-my-pants excited to announce that next week I’ll be joining the team at Braintree and Venmo to work on their JavaScript SDK.

Now that my job search is over, I want to share the lessons I learned from interviewing as a software engineer 2 years into my career. Most of these are not new (or specific to being 2 years into your career), but these points are what specifically helped me the most.

Intro to Angular.js Talk

Mon, 28 Apr 2014 23:40:24 +0000

On April 24 I gave a talk, Introduction to Angular.js, to the SF HTML5 Live Code meetup group. Here’s the screencast:

Things learned while preparing for Angular Live Code

Tue, 22 Apr 2014 00:00:00 +0000

This week I learned that there’s nothing quite like signing up to teach something to make you realize you don’t actually know the material all that well.

I’m giving an introduction to AngularJS talk this Thursday at Startup House SF. You should come by if you want to learn about AngularJS.

It’s Tuesday and 124 people have signed up and I’m kind of nervous to say the least. I’ve tried to channel my nervousness into preparation (we’ll see if it pays off or not). Here are a few things I’ve learned in the process.

Prim's Algorithm in ClojureScript

Sat, 05 Apr 2014 16:24:34 -0700

If you want to jump to the animation in its natural habitat, see it here. If you want to jump to the code: see the ClojureScript or JavaScript on GitHub.

After being interested in maze generation and after checking out the Wikipedia page, I thought it’d be cool to implement one in JavaScript. After that, it looked like a good opportunity to try porting some JavaScript to ClojureScript.

For the sake of brevity I’m leaving some of the more boilerplate functions out of this post. For the full code in each language, see the GitHub links above.

Two interesting IE JavaScript quirks

Fri, 14 Mar 2014 00:00:00 +0000

In the past month I’ve diagnosed and fixed a couple particularly pernicious bugs relating to JavaScript quirks in Internet Explorer. Hopefully if you haven’t run into these before, this will save you some pain in the future.

1. `window` does not inherit from `Object.prototype`

Oddly enough, according to the ECMAScript specification, the global window object does not necessarily have to inherit from Object.prototype. In Chrome, FF, and Safari, it does, but in IE it does not.

JavaScript's Mutative vs. Non-Mutative Array Methods

Thu, 20 Feb 2014 12:00:04 +0000

This is an issue that has endlessly tripped me up in JavaScript and I hope this post will help clarify things a bit and hopefully discover a pattern one can use to discern between mutative and non-mutative array methods.

First, let me define what I mean when I say mutative:

// If a method is mutative, that means it changes the original array.
var foo = [1, 2, 3];
foo.reverse();
console.log(foo); // [3, 2, 1]

// Notice how we didn't assign foo to new variable, reverse() acted upon it in place.
// In contrast, non-mutative array methods return a new copy of the original array.

// Here, the new array concat() generates is lost since we didn't assign it
var bar = [1, 2, 3];
bar.concat([4, 5]);
console.log(bar); // [1, 2, 3]

// Now if we assign it, bar becomes the new array.
bar = bar.concat([4, 5]);
console.log(bar); // [1, 2, 3, 4, 5]

Mutative	Non-Mutative
splice	slice
shift, pop	concat
unshift, push	every *
reverse	filter *
sort	forEach *
	indexOf
	lastIndexOf
	join
	map *
	reduce *
	reduceRight *
	some *
	toLocaleString
	toString

NB: the functional methods marked with a * can be mutative if the function you pass to them modifies the original array. In my expierience this has been especially true in the case of Array.prototype.forEach.

Hello World, Again

Sat, 08 Feb 2014 00:00:00 +0000

I’ve tried numerous times to start a consistently updated blog. The main deterring factor is that any time I go back and read my writing from a week/month/year ago, I cringe.

Maybe the reason I cringe is because I was blogging for the wrong reasons.

This isn’t the part where I start pontificating what blogging should be about, but I think what motivated me before was some vague need to toot my own horn, or (god forbid) build by “personal brand.”

Japanese Programming

Mon, 25 Feb 2013 00:00:00 +0000

I’m certainly guilty of being a little to anglo-centric from time to time (pizza is an American food, right?), so I was pleasantly surprised when I found out that you can program in languages other than English. You can see the full list on Wikipedia. Since I’m into both computers and Japan, I thought I’d give a few of them a spin.

Dolittle ドリトル

According to its Wikipedia page, Dolittle is a programming language for education developed by Osaka Electro-Communication University. Its creators called it Dolittle because they wanted to make a programming language that made it very easy to start programming.

Pechakucha Waterville Talk

Tue, 01 May 2012 16:33:54 -0700

Here’s the talk I gave at Pechakucha Waterville my senior year at Colby College. I talk about my filmmaking and quantified-self pursuits during my time at Colby.

Ueno Zoo 上野動物園

Tue, 07 Feb 2012 00:00:00 +0000

Yes, it is February and I am back in Maine. But the tale of my stay in Japan has not been completely told.

On a warmer-than-normal day in late January, my Colby friend Stephanie and I ventured up to Ueno to visit the famous Ueno zoo.

Our first stop was naturally the panda exhibit.

Tsukiji Fish Market 築地市場

Thu, 02 Feb 2012 00:00:00 +0000

Located in the middle of Tokyo, Tsukiji Fish Market, or tsukiji uchiba (築地市場), is the biggest fish market in the world. On my last weekend I woke up early in the morning and headed over there with my Colby friend.

Editor's note: Tsukiji closed down in 2018 and moved to Toyosu for the 2020 Olympics.

The market is filled with more sea life than an aquarium, although calling it sea “life” might be a little misleading.

January in Japan

Wed, 01 Feb 2012 00:00:00 +0000

I spent January 2012 Tokyo, Japan interning at a Japanese advertising agency. Beforehand I spent some time in Osaka and Kyoto, the region where I studied abroad in 2010. Here are some highlights of my travels.

Kiyomizudera 清水寺

Kiyomizu is one of the oldest, most beautiful, and most popular temples in Kyoto. It was constructed entirely without the use of nails. Legend has it that if you jump off the deck and survive the 13 meter fall, your life dream will come true.
Full post here.

Tokyo Tower 東京タワー

Fri, 27 Jan 2012 12:54:51 -0700

Come on, did you think I was going to be in Tokyo for a month and not do the most touristy thing you could possibly do in Tokyo - go up Tokyo Tower?

Nara 奈良

Sat, 07 Jan 2012 12:54:51 -0700

I have to preface this post with my extreme gratitude for my friend Shintaro’s family, who hosted me for the new year oshōgatsu お正月 and took me on their hatsumōde 初詣. I can’t thank them enough for their hospitality.

Hatsumōde is the practice of going to a shrine or temple on the first few days of the year. For Shintaro’s family’s hatsumōde, we went to Nara.

Fushimi Inari-taisha 伏見稲荷大社

Thu, 05 Jan 2012 12:54:51 -0700

伏見 Fushimi is the ward of Kyoto where this shrine is located.

稲荷 Inari is the Shinto deity to whom this shrine is dedicated.

大社 Taisha means “big shrine.”

On the last day of the year, I got the chance to go back to Kyoto to see a couple more shrines. There was one left that I needed to hit. (And by ‘one’, I mean over a thousand).

Kiyomizu Temple 清水寺

Tue, 03 Jan 2012 12:54:51 -0700

After arriving at Hirakata and sleeping in late, my friends and I went to Kyoto to see Kiyomizu temple. 清水寺 (kiyomizu-dera) was one of the places I wanted to go while I was studying abroad there in 2010, but never got the chance.

Study abroad friends who joined me.

Kiyomizu is one of the most popular temples in Kyoto along with the Kinkaku-ji (Golden Pavilion). The impression I got is that Kiyomizu is all about making dreams come true (not in the Disney theme park sense).

Osaka Aquarium 海遊館

Tue, 03 Jan 2012 12:54:51 -0700

Osaka Aquarium is called the “Kaiyukan,” or sea 海 play 遊 building 館. I noticed two main differences between American aquariums and the Kaiyukan.

All of the sea life at the Kaiyukan was really happy and lively. I don’t know what they feed the animals, but it’s working.
They have a penguin parade.

Several times a day, the staff will waddle a gaggle of penguins around a the front of the Kaiyukan. I came to the conclusion that this kind of thing couldn’t happen in America because too many people like me would be tempted to steal one.

Study Abroad in Japan

Mon, 03 Jan 2011 12:54:51 -0700

In Fall 2010 I studied abroad at Kansai Gaidai University. It was an awesome experience. Here’s a video I made about it.

Huge Snow

Wed, 21 Apr 2010 00:00:00 +0000

We’ve been having a warm, sunny spring here in Maine, so it was a surprise a couple days ago when a huge snowstorm hit out of nowhere. The snow lasted for about half a day, and then it returned to being sunny and nice.

NPR Station Summer Internship Recap

Wed, 21 Apr 2010 00:00:00 +0000

This summer I interned in the news desk at WBUR, an NPR station in Boston known for Car Talk and Here & Now. Here are some videos I helped produce.

Mon, 01 Jan 0001 00:00:00 +0000

The best couple things I read this month
Updates on personal projects

View previous newsletters here, and my earlier TinyLetter posts here.

Quotes

Mon, 01 Jan 0001 00:00:00 +0000

To bear up under loss, to fight the bitterness of defeat and the weakness of grief, to be victor over anger, to smile when tears are close, to resist evil men and base instincts, to hate hate and to love love, to go on when it would seem good to die, to seek ever after the glory and the dream, to look up with unquenchable faith in something evermore about to be, that is what any man can do, and so be great.