HNHacker News
TopNewBestAskShowJobs

jrevels

148 karma · joined May 3, 2016

submissionscomments
jrevels··on NumPy-style broadcasting in Futhark
Cool stuff! Thanks for the write-up. Getting broadcast ergonomics right in a fully statically typed context seems both tricky and pretty satisfying.

> We thought it’d be a fun/simple feature and a good break from the heavy duty work on automatic differentiation we had just published

Perhaps it wasn't as much of a break as you might think - funnily enough, static broadcast semantics can serve as an interesting structural foothold for certain AD optimizations [1]

(disclaimer: I'm a coauthor on that paper :) but it's been quite a while since I've done work in the AD space)

[1] https://arxiv.org/pdf/1810.08297

jrevels··on Ask HN: Who is hiring? (February 2022)
Beacon Biosignals | Multiple Positions | NYC, Boston, Remote | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available, and are always happy to chat with interested folks. Interested in working with PostgreSQL, Typescript, React, and/or Julia daily? Reach out!

To apply, check out https://beacon.bio/careers.

jrevels··on Ask HN: Who is hiring? (January 2022)
Beacon Biosignals | Multiple Positions | NYC, Boston, Remote | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available, and are always happy to chat with interested folks. Interested in working with PostgreSQL, Typescript, React, and/or Julia daily? Reach out!

To apply, check out https://beacon.bio/careers.

jrevels··on Beacon Biosignals raises $27M to scale EEG neurobiomarker discovery
Good questions!

> How exactly does Julia fit into your software architecture?

In a variety of ways:

- We have a bunch of external/internal Julia packages; Julia's package manager is really great at facilitating the development of "tooling ecosystems" comprised of lightweight libraries that compose well together. For example, we use Legolas.jl [1] in conjunction with a well-curated Arrow-in-S3 lake to help teams define lightweight, self-serviceable schemas for Arrow tables in a manner that integrates well with the wider Tables.jl ecosystem [2], interactive analysis workflows, and our own ETL/ELT-ish patterns.

- Julia powers some interesting services within Beacon's Platform. For example, one of our Julia services provides dynamic streaming DSP (multiplexing, filtering, statistics) for biosignal data, atop which we build other applications/pipelines for both product development and internal analysis work.

- We use Julia for exploratory distributed computing on K8s [3], which is awesome because Julia has a lot of potential in the distributed computing landscape (IMO [4]).

> Is your product a cloud offering and/or does it have a client side application?

We work with our clients to do neurobiomarker discovery, clinical trial design, deploy our analysis pipelines into clinical trials, and a few other interesting things :) One of the critical differentiators of Beacon is that we can precisely target and harness key EEG features to a degree that isn't possible without the kind of algorithms/tools we've developed.

> what do you even mean by data architecture for science-first teams

I want to do a blog post on this at some point, but a core value for us - across all of our processes, tooling, and data interactions - is self-serviceability and composability. IMO, the two are inextricably linked. Our goal is to empower each Beaconeer to perform analyses in an afternoon atop terabytes of data that would take them months in a lab atop gigabytes of data.

To achieve this, we treat large-scale data curation/manipulation as an activity that we're all empowered to participate in and contribute to, as opposed to an environment where separate data engineering teams have to administrate siloed systems. Tools like K8s/Julia/Arrow are key enablers here, by surfacing capabilities to domain experts that let them to iterate fast without needing to "throw problems over the wall" to other teams/systems.

It's not a perfect match, and it's a bit abstract, but I remember reading this post about "data meshes" [5] a while back and thinking "Hey, that's similar to what we're chasing after!"

[1] https://github.com/beacon-biosignals/Legolas.jl

[2] https://github.com/JuliaData/Tables.jl

[3] https://github.com/beacon-biosignals/K8sClusterManagers.jl

[4] https://news.ycombinator.com/item?id=24842084

[5] https://martinfowler.com/articles/data-mesh-principles.html

jrevels··on Beacon Biosignals raises $27M to scale EEG neurobiomarker discovery
Cofounder here :) Happy to answer any questions about scaling Julia on K8s, data architecture for science-first teams, and our weird/wild journey to get to this point.

We are, of course, hiring - check out https://beacon.bio/careers!

jrevels··on Ask HN: Who is hiring? (November 2021)
Beacon Biosignals | Multiple Positions | NYC, Boston, Remote | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available, and are always happy to chat with interested folks. Interested in working with PostgreSQL, React, and/or Julia daily? Reach out!

To apply, check out https://beacon.bio/careers.

jrevels··on Ask HN: Who is hiring? (October 2021)
Beacon Biosignals | Multiple Positions | NYC & Boston | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available, and are always happy to chat with interested folks. Interested in working with PostgreSQL, React, and/or Julia daily? Reach out!

To apply, check out https://beacon.bio/careers.

jrevels··on Ask HN: Who is hiring? (April 2021)
Beacon Biosignals | Multiple Positions | Boston, MA | Remote | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available, and are always happy to chat with interested folks! To apply, check out https://beacon.bio/careers.

jrevels··on Ask HN: Who is hiring? (March 2021)
Beacon Biosignals | Senior Engineering Manager, Technical Program Manager | Boston, MA | Remote | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available, and are always happy to chat with interested folks! To apply, check out https://beacon.bio/careers.

jrevels··on Apache Arrow 3.0
Excited to see this release's official inclusion of the pure Julia Arrow implementation [1]!

It's so cool to be able mmap Arrow memory and natively manipulate it from within Julia with virtually no performance overhead. Since the Julia compiler can specialize on the layout of Arrow-backed types at runtime (just as it can with any other type), the notion of needing to build/work with a separate "compiler for fast UDFs" is rendered obsolete.

It feels pretty magical when two tools like this compose so well without either being designed with the other in mind - a testament to the thoughtful design of both :) mad props to Jacob Quinn for spearheading the effort to revive/restart Arrow.jl and get the package into this release.

[1] https://github.com/JuliaData/Arrow.jl

jrevels··on Ask HN: Who is hiring? (January 2021)
Beacon Biosignals | Multiple Positions | Boston, MA | Remote | Full Time

Brain monitoring is not easily accessible, interpretable or actionable. We're going to fix this, and we'd like you to help.

With improved access to brain data and the right tools to act on it, clinicians could intervene in real-time, match life-altering therapies to the patients they benefit most, and treat previously untreatable neurological and psychiatric diseases.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond.

Our team is composed of neuro-experts, product development experts, open-source enthusiasts, audio/DSP/compilers nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available (Ops Engineer, Program Manager, Director of Design, etc.), and are always happy to chat with interested folks! To apply, check out https://beacon.bio/careers.

jrevels··on The Accelerating Adoption of Julia
I think one of Julia's greatest indicators of long-term success is the variety of commercial users/companies from a diverse pool of technical domains/industries that are all excited, willing, and capable of contributing back to the ecosystem.

We had a BoF at this year's JuliaCon revolving around this topic [1] and are now planning the first Annual Industry Julia Users Contributhon as a result.

I especially think that well-configured Julia + K8s setups have the capacity to really tighten exploratory data science <-> operational data engineering feedback loops in industrial settings in a way that is much more ergonomic, generically useful, and portable/extensible than using pre-baked frameworks to achieve something similar. Julia-centric tooling for coarse-grained workflow orchestration, experiment tracking, data provenance, etc. would be nice, though I also think existing generic tools in this vein (e.g. Argo) could probably compose well too :)

A few different companies have nice in-house implementations of these kinds of setups, and Julia Computing is building a nice looking commercial product suite in this vein that I look forward to exploring more in the future (especially JuliaHub and JuliaRun).

[1] https://julialang.org/blog/2020/09/juliacon-2020-open-source...

jrevels··on Ask HN: Who is hiring? (October 2020)
Beacon Biosignals | Multiple Positions | Boston, MA | Remote | Full Time

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible, interpretable or actionable in many clinical environments. A lack of reliable strategies for data-driven patient stratification massively hinders the development and deployment of potentially life-altering interventions for devastating neurological ailments.

We're going to fix this, and we'd like you to help.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of neuro-experts, open-source enthusiasts, audio/DSP engineers, programming language nerds, and generally easy-going (but dedicated!) folks.

We believe that:

- Successful product development requires rapid, early feedback from real patients and clinicians.

- Feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- A diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available (Data Engineering, DevOps, etc.), and are always happy to chat with interested folks! To apply, check out https://beacon.bio/careers.

jrevels··on Transitioning Code from Closed to Open: Industry Julia Users Discuss OSS
Author of post here. I tried to distill as much of this JuliaCon session's content as possible; hopefully didn't miss too much. I'd be keen to hear about OSS hurdles that I'm sure folks have faced in other language communities :)

It's kind of nestled at the bottom, but this post also announces that we're organizing the first ever "Annual Industry Julia Users Contributhon", an annual Julia community hackathon where participating industry organizations can come together to contribute back to the Julia ecosystem. We already have a great cohort of orgs that I'm positive will produce some substantial contributions over what's sure to be a fun couple of days. If your company uses Julia, I'd love for you to join us!

jrevels··on Ask HN: Who is hiring? (September 2020)
Beacon Biosignals | Multiple Positions | Boston, MA | Remote | Full Time

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible, interpretable or actionable in many clinical environments. A lack of reliable strategies for data-driven patient stratification massively hinders the development and deployment of potentially life-altering interventions for devastating neurological ailments.

We're going to fix this, and we'd like you to help.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of neuro-experts, open-source enthusiasts, audio/DSP engineers, programming language nerds, and generally easy-going (but dedicated!) folks. We're adamant that...

- ...successful product development requires rapid, early feedback from real users.

- ...feats of technical wizardry are only useful in combination with honest, frequent, and open communication.

- ...a diverse team builds more robust systems and practices more meaningful science.

We have a few different roles available (Data Engineering, DevOps, etc.), and are always happy to chat with interested folks! To apply, check out https://boards.greenhouse.io/beaconbiosignals.

jrevels··on Ask HN: Who is hiring? (August 2020)
Beacon Biosignals | Multiple Positions | Boston, MA | Remote | Full Time

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible, interpretable or actionable in many clinical environments. A lack of reliable strategies for data-driven patient stratification massively hinders the development and deployment of potentially life-altering interventions for devastating neurological ailments.

We're going to fix this, and we'd like you to help.

We're a small startup founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of neuro-experts, open-source enthusiasts, audio/DSP engineers, programming language nerds, and generally easy-going (but dedicated!) folks. We're adamant that...

- ...product development goes off the rails without rapid, early feedback from real users and domain experts.

- ...feats of technical wizardy are mostly useless without honest, frequent, and open communication.

- ...diversity is an integral part of strong engineering culture. Differing viewpoints are borne from differing backgrounds, and lack of diversity contributes to stagnation.

We have a few different roles available (Data Engineering, DevOps, etc.), and are always happy to chat with interested folks! To apply, check out https://boards.greenhouse.io/beaconbiosignals.

jrevels··on Ask HN: Who is hiring? (March 2020)
Beacon Biosignals | UI/UX Engineer |Boston, MA | Onsite Available, Remote Friendly | Full Time

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible or interpretable in clinical settings. We're going to fix that, and we'd like you to help.

We're founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond. We're adamant 1) that product development goes off the rails without rapid, early feedback from real users 2) that honest, frequent, and open communication are more significant contributors to software development than technical wizardry and 3) that differing viewpoints are borne from differing backgrounds, and lack of diversity contributes to stagnation.

About You:

- You're an expert in the client-side design and implementation of responsive, multi-platform web applications.

- You believe that "looks great" does not necessarily equal "feels great"...but your favorite applications accomplish both!

- You know that UX/UI optimization for expert users is a game in which minuscule details can wreck workflows or convert users to evangelists in equal measure.

- You're annoyed that modern websites ship megabytes of unnecessary dependencies to user's browsers.

- You have a heavily-exercised workflow for debugging performance issues and deciding which layer of the stack merits optimization.

- You recognize the tension in the development feedback loop between client- and service-side environments, and derive immense satisfaction from improving development processes to tighten that loop.

- Your productivity bottleneck constantly switches between "idea-to-mockup time" and "mockup-to-implementation" time, because you're constantly improving both in turn.

- You're excited for your designs to lead to better workflows for clinicians and better outcomes for patients.

Contact jarrett@beacon.bio/jake@beacon.bio if interested.

P.S. We're also hiring for various Data Engineer/Scientist roles!

jrevels··on Ask HN: Who is hiring? (February 2020)
Beacon Biosignals | Senior Machine Learning Engineer |Boston, MA | Onsite Available, Remote Friendly | Full Time

About Us:

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible or interpretable in clinical settings. We're going to fix that, and we'd like you to help.

We're founded by numerical programmers, neuroscientists, ML researchers, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into hospitals and beyond. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world.

Our team is composed of neuro-experts, open-source enthusiasts, audio/DSP engineers, programming language nerds, and generally easy-going (but dedicated!) folks. We're adamant that...

- ...product development goes off the rails without rapid, early feedback from real users.

- ...honest, frequent, and open communication are more significant contributors to software development than technical wizardry.

- ...diversity is an integral part of strong engineering culture. Differing viewpoints are borne from differing backgrounds, and lack of diversity contributes to stagnation.

About You:

- You realize that lowering hypothesis test turnaround time from months to minutes requires applying best-of-breed DevOps concepts to the data science workflow.

- You can't wait to combine your background with our unprecedented EEG dataset to blow published statistical EEG results out of the water.

- You will discover and formulate techniques for analysis that haven't even been attempted with EEG outside of Beacon due to lack of data and/or infrastructure (e.g. "How might we refactor our existing spike detection algorithm to achieve high inter-rater agreement on noisy signals across a reduced set of channels?")

- You'll help develop new methodologies for aggregating a vast quantity of labels from expert neurologist readers of differing backgrounds and opinions.

- You've developed a solid, heavily-exercised workflow for debugging model performance; you now know more about the limitations of automatic differentiation and distributed heterogeneous computing than you ever thought you would when you started your ML journey (e.g. "How can I alter this model's architecture to mitigate the decrease in sample throughput once I lower the minibatch size?")

- You will help steer engineering efforts to standardize, improve, and automate our model development/deployment lifecycle and related tooling.

- You'll provide constant feedback about what we do wrong and how we can do better.

- As Beacon grows, you'll have the opportunity to build and lead teams that accomplish all of the above - tenfold!

- You'll have the opportunity to co-author scientific papers whose impact pushes the neurocritical care, neuroscience, and machine learning communities past contemporary limitations.

- PhD in relevant field or equivalent research engineering experience.

Our data science team makes heavy use of the Julia language. This quarter, we're pushing >70TB of signal data (and our processes for manipulating it) into AWS, where we're developing a deep learning platform for rapid hypothesis testing, sleek data visualization, and interactive analysis exploration. Come help us make the right decisions!

Contact jarrett@beacon.bio if interested.

jrevels··on Ask HN: Who is hiring? (December 2019)
Beacon Biosignals | Lead Operations Engineer | Boston, MA | Onsite Available, Remote Friendly | Full Time

Our super early-stage startup is seeking an individual to lead the development/operations of our AWS infrastructure, and along the way teach us all how to deliver more robust software.

About Us:

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible or interpretable in clinical settings. We're going to fix that, and we'd like you to help.

We're a semi-stealth-mode startup founded by numerical programmers, neuroscientists, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into the ICU and ED. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of neuro-experts, open-source enthusiasts, audio/DSP engineers, programming language nerds, and generally easy-going (but dedicated!) folks.

About You:

- You're excited to design a service architecture that orthogonalizes the critical feedback loops that entangle our code, data, models, and products.

- You're tired of organizations treating DevOps like an individual role instead of a company-wide practice.

- You're a networks/containers nerd who will turn us into networks/containers nerds.

- You've witnessed the pains that result from fitting square AWS-provided-solution pegs into round in-house-problem holes. Conversely, you've also seen how NIH syndrome can drive teams down a rabbit hole whose endpoint is a shallow reproduction of an existing AWS solution that could've just been employed in the first place.

- You are familiar with the many idiosyncrasies of storing, streaming, and analyzing large volumes of dense signal data in the cloud (e.g. audio, video, domain-specific sensor data, etc.).

- You believe that diversity is an integral part of strong engineering culture, and that lack of diversity contributes to stagnation.

Our data science team makes heavy use of the Julia language. This quarter, we're tackling model evaluation as a CI process, pushing >70TB of signal data (and our processes for manipulating it) into AWS, and developing a browser-based viewing/analysis application for our signal data. Come help us make the right decisions!

Contact jarrett@beacon.bio if interested.

jrevels··on Ask HN: Who is hiring? (November 2019)
Beacon Biosignals | Lead Operations Engineer | Boston, MA | Onsite Available, Remote Friendly | Full Time

Our super early-stage startup is seeking an individual to lead the development/operations of our AWS infrastructure, and along the way teach us all how to deliver more robust software.

About Us:

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible or interpretable in clinical settings. We're going to fix that, and we'd like you to help.

We're a semi-stealth-mode startup founded by numerical programmers, neuroscientists, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into the ICU and ED. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of neuro-experts, open-source enthusiasts, audio/DSP engineers, programming language nerds, and generally easy-going (but dedicated!) folks.

About You:

- You're excited to design a service architecture that orthogonalizes the critical feedback loops that entangle our code, data, models, and products.

- You're tired of organizations treating DevOps like an individual role instead of a company-wide practice.

- You're a networks/containers nerd who will turn us into networks/containers nerds.

- You've witnessed the pains that result from fitting square AWS-provided-solution pegs into round in-house-problem holes. Conversely, you've also seen how NIH syndrome can drive teams down a rabbit hole whose endpoint is a shallow reproduction of an existing AWS solution that could've just been employed in the first place.

- You are familiar with the many idiosyncrasies of storing, streaming, and analyzing large volumes of dense signal data in the cloud (e.g. audio, video, domain-specific sensor data, etc.).

- You believe that diversity is an integral part of strong engineering culture, and that lack of diversity contributes to stagnation.

Our data science team makes heavy use of the Julia language. This quarter, we're tackling model evaluation as a CI process, pushing >70TB of signal data (and our processes for manipulating it) into AWS, and developing a browser-based viewing/analysis application for our signal data. Come help us make the right decisions!

Contact jarrett@beacon.bio if interested.

jrevels··on Ask HN: Who is hiring? (October 2019)
Beacon Biosignals | Lead Front-End Engineer | Boston, MA | Onsite Available, Remote Friendly | Full Time

About us:

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible or interpretable in clinical settings. We're going to fix that, and we'd like you to help.

We're a stealth-mode startup founded by numerical programmers, neuroscientists, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into the ICU and ED. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of open-source enthusiasts, former audio/DSP engineers, programming language nerds, and generally easy-going, fun-loving, dedicated folks.

About you:

- You know that product development goes off the rails without rapid, early feedback from real users.

- You believe that "looks great" does not necessarily equal "feels great", and that the latter is higher priority (but your favorite applications accomplish both!).

- You feel that diversity is an integral part of strong engineering culture. Differing viewpoints are borne from differing backgrounds, and lack of diversity contributes to stagnation.

- You're annoyed that modern websites ship megabytes of unnecessary dependencies to user's browsers. You're painfully aware of the difference between "DRY" as an important guiding principle of software development, and "DRY" as a cargo-cult mentality used to justify lazy over-coupling of code.

- You simultaneously hate and love Javascript, and are excited about various LLVM-based languages' recent progress targeting WebAssembly.

- You have a battle-tested workflow for debugging performance issues and deciding which layer of the stack merits optimization.

- You sigh at bullet-pointed job descriptions that try to prescribe visceral emotional reactions to technical opinions.

Outside of the browser, our data science team makes heavy use of the Julia language. Our nascent tooling for serving data to the browser is written in Julia as well. We're still experimenting with various parts of our tech stack, however - come help us make the right decisions!

Contact jarrett@beacon.bio if interested.

P.S. We're also hiring for Lead Android and Lead DevOps roles!

jrevels··on Ask HN: Who is hiring? (September 2019)
Beacon Biosignals | Lead Front-End Engineer | Boston, MA | Onsite Available, Remote Friendly | Full Time

About us:

Despite its significant potential for improving patient outcomes, brain monitoring is still not easily accessible or interpretable in clinical settings. We're going to fix that, and we'd like you to help.

We're a stealth-mode startup founded by numerical programmers, neuroscientists, and practicing neurologists who are committed to translating our best-of-breed clinical research from the lab into the ICU and ED. We're well-funded, well-connected, and own a well-labeled set of brain data amassed over the past decade at some of the most prestigious medical institutions in the world. This dataset is, as far as we know, the largest of its kind in existence. We intend to put it to good use.

Our team is composed of open-source enthusiasts, former audio/DSP engineers, programming language nerds, and generally easy-going, fun-loving, dedicated folks.

About you:

- You know that product development goes off the rails without rapid, early feedback from real users.

- You believe that honesty and frequent, open communication are more signficant contributors to software development than technical wizardy.

- You believe that "looks great" does not necessarily equal "feels great", and that the latter is higher priority (but your favorite applications accomplish both!).

- You want to build tools that help people help others in critical environments.

- You feel that diversity is an integral part of strong engineering culture. Differing viewpoints are borne from differing backgrounds, and lack of diversity contributes to stagnation.

- You're annoyed that modern websites ship megabytes of unnecessary dependencies to user's browsers. You're painfully aware of the difference between "DRY" as an important guiding principle of software development, and "DRY" as a cargo-cult mentality used to justify lazy over-coupling of code.

- You simultaneously hate and love Javascript, and are excited about various LLVM-based languages' recent progress targeting WebAssembly.

- You nerd out about content-specific adaptive streaming and compression techniques.

- You think Observable notebooks are really cool.

- You have a battle-tested workflow for debugging performance issues and deciding which layer of the stack merits optimization.

- From a front-end perspective, you recognize the tension in the development feedback loop between client-side software and a back-end service ecosystem, and derive immense satisfaction from improving development processes to relieve those tensions.

- You're intimately familiar with the lifecycle of software components - from experiment, to prototype, to an incremental release schedule.

- You sigh at bullet-pointed job descriptions that try to prescribe visceral emotional reactions to technical opinions.

Our data science team makes heavy use of the Julia language, and are still experimenting with various parts of our tech stack. Come help us make the right decisions!

Contact jarrett@beacon.bio if interested.

P.S. We're also hiring for Lead Android and Lead DevOps roles!

jrevels··on Dynamic Automatic Differentiation of GPU Broadcast Kernels [pdf]
Sure!

So, essentially, most ML frameworks' expressivity is heavily constrained by what the framework knows how to "efficiently" differentiate, generally via AD. Our paper presents a technique for improving many ML frameworks' AD implementations for a really common class of operations ("broadcast" operations) in a way that not only benefits performance, but benefits programmability as well.

More specifically, right now, ML frameworks mainly only support one kind of AD (reverse-mode). There's another kind of AD (forward-mode) that is more efficient in certain cases (and less efficient in others). Furthermore, certain programmatic constructs (like broadcasting certain kinds of kernels) are intractable to differentiate on a GPU in reverse-mode can be tractable if you utilize forward-mode instead.

It's generally a hard problem to combine the two modes in an optimal manner. However, we present a technique that enables the implementer to easily interleave the two modes specifically for differentiating broadcast operations. Our technique also removes some barriers to important compiler-level optimizations (like operator fusion), and thus can improve performance.

> I have never heard the term 'broadcasting' in this context

If you've used numpy, you've likely used this kind of "broadcasting"; AFAIK it was numpy that popularized the use of the term "broadcasting" for this operation in Python (though I'm no Python historian, so take that with a grain of salt).

jrevels··on Dynamic Automatic Differentiation of GPU Broadcast Kernels [pdf]
I'll forward this to some of my GPU-expert-coauthors in the morning to see if they have a take on your questions. I think there's a few interesting facets here, though, so here's my take.

> What's the most notable way the GPU in particular comes into play?

Forward-mode and reverse-mode AD have different expressibility constraints on the kinds of programs that each can efficiently target in the face of dynamism, and GPUs also have fairly constrained programming models compared to the CPU. For me, a big part of the paper was the exploration of the intersection of these two sets of programmability constraints.

Section 2.2.4 and the experimental sections explain some of this in detail, but I think one of the more surprising results was that the benefits of fusing dynamic control flow into the broadcasted derivative kernel outweighed potential detriments e.g. warp divergence. It turns out newer GPU architectures give you more leeway in that regard than any of us on the team expected.

> How does caching come into play?

Depends on which kind of "caching" you're referring to.

If you mean tape-level partial derivative caching/memory usage:

Broadcasting a forward-mode derivative operator, as presented in this paper, can save on memory when it enables better fusion than reverse-mode on complicated kernels (resulting in fewer temporaries).

However, there is also a question of when this technique should actually be employed: during the forward pass, or during the reverse pass? If employed in the forward pass, then the primal and partial derivative calculations can be fused, reducing compute cost. However, doing so means that the memory required to store the partial derivatives is held captive until those derivatives can be backpropagated in the reverse pass. Conversely, employing the technique in the reverse pass allows you to free the partial derivative storage quickly, but features some redundant computation. Section 2.2.3 of the paper discusses this a bit.

If you mean instruction-level caching, i.e. efficient pipelining of memory into registers:

On the CPU, it's quite easy to thrash cache for high-arity dual number calculations (i.e. calculations where dual number instances carry around a long stack-allocated array of partial derivatives). Our experiment in Section 3.4.1 tries to characterize the analogous GPU behavior by measuring how occupancy scales with target calculation arity.

Also, there was definitely a bit of implementation work to ensure that loads from our GPU-backed "dual number" arrays coalesced properly, that indexing calculations were compiled away when possible, etc. The cool part is that the dual numbers themselves were just the implementation provided by the ForwardDiff package (https://github.com/JuliaDiff/ForwardDiff.jl), which contains no GPU-specific specialization, and they're automagically JIT-compiled for the GPU by CUDAnative (https://github.com/JuliaGPU/CUDAnative.jl).

> What about intrinsic condensing functions?

Hmm...I'm not positive I know what "intrinsic condensing functions" are. Apologies!

jrevels··on Dynamic Automatic Differentiation of GPU Broadcast Kernels [pdf]
Author here; the arxiv version can be found at https://arxiv.org/abs/1810.08297. Not much different from OP's linked version, but it includes citations to other interesting Julia AD/TPU-related papers that utilize this technique.

Happy to answer any questions, at least until I turn in for the night :)

jrevels··on Julia parallel task runtime (WIP)
This work has been a monumental collaborative effort and I think the eventual outcome will be pretty spectacular.

I gave a talk at an MIT Julia meetup a few months ago that the author of this PR also spoke at; I found his talk to be an insightful overview of this work: https://www.youtube.com/watch?v=YdiZa0Y3F3c

jrevels··on Nim Programming Language v0.16.0 released
Might want to check out Plots.jl [1], which is pretty quickly becoming the de facto plotting library for many Julia users. It abstracts over various plotting backends, including native Julia graphics libraries like GLVisualize.jl [2] (which IMO has amazing potential for simulation visualizations once native graphics programming in Julia matures).

I hear the normal PyPlot/GR wrappers are pretty useful as well. They're ultimately not native Julia code, but since Julia makes it so easy to reuse tools in other languages, why not take advantage of that feature?

[1] https://juliaplots.github.io/

[2] https://github.com/JuliaGL/GLVisualize.jl