I'm liking the class this year. Students are attentive and participating, and the discussion is always productive.

We were discussing the rounding up of the launch grid in #OpenCL to avoid the catastrophic performance drops that come from the inability to divide the “actual” work size by anything smaller than the maximum device local work size, and were discussing on how to compute the “rounded up” work size.

The idea is this: given the worksize N and the local size L, we have to round N to the smallest multiple of L that is not smaller than N. This effectively means computing D = ceili(N/L) and then using D*L.

There are several ways to compute D, but on the computer, working only with integers and knowing that integer division always rounded down, what is the “best way”?

D = N/L + 1 works well if N is not a multiple of L, but gives us 1 more than the intended result if N *is* a multiple of L. So we want to add the extra 1 only if N is not a multiple. This can be achieved for example with

D = N/L + !!(N % L)

which leverages the fact that !! (double logical negation) turns any non-zero value into 1, leaving zero as zero. So we round *down* (which is what the integer division does) and then add 1 if (and only if) there is a reminder to the division.

This is ugly not so much because of the !!, but because the modulus operation % is slow.

1/n

If only #ROCm is better supported by #AI tools...

I know #CUDA is much more mature and widely supported, but Nvidia support on Linux sucks. Also #OpenCL support is even less popular.

Also, #AMD is much friendlier to my bank account.

@dexter Here's the AMD w/ CUDA support/library/api/shim/translation/thing that came up the other day:

> ZLUDA is a drop-in replacement for CUDA on non-NVIDIA GPU. ZLUDA allows to run unmodified CUDA applications using non-NVIDIA GPUs with near-native performance.

- https://vosen.github.io/ZLUDA/blog/zludas-third-life/
- https://github.com/vosen/ZLUDA

A week ago was the 1st anniversary of this solo instance & more generally of my fulltime move to Mastodon. A good time for a more detailed intro, partially intended as CV thread (pinned to my profile) which I will add to over time (also to compensate the ongoing lack of a proper website)... Always open to consulting offers, commissions and/or suitable remote positions...

Hi, I'm Karsten — indy software engineer, researcher, #OpenSource author of hundreds of projects (since ~1999), computational/generative artist/designer, landscape photographer, lecturer, outdoor enthusiast, on the ND spectrum. Main interest in transdisplinary research, tool making, exploring techniques, projects & roles amplifying the creative, educational, expressive and inspirational potential of (personal) computation, code as material, combining this with generative techniques of all forms (quite different to what is now called and implied by "generative AI").

Much of my own practice & philosophy is about #BottomUpDesign, interconnectedness, simplicity and composability as key enablers of emergent effects (also in terms of workflow & tool/system design). Been adopting a round-robin approach to cross-pollinate my work & learning, spending periods going deep into various fields to build up and combine experience in (A-Z order): API design, audio/DSP, baremetal (mainly STM32), computer vision/image processing, compiler/DSL/VM impl, databases/linked data/query engines, data structures impl, dataviz, fabrication (3DP, CNC, knit, lasercut), file formats & protocols (as connective tissue), "fullstack" webdev (front/back/AWS), generative & evolutionary algorithms/art/design/aesthetics/music, geometry/graphics, parsers, renderers, simulation (agents/CFD/particles/physics), shaders, typography, UI/UX/IxD...

Since 2018 my main endeavor has been https://thi.ng/umbrella, a "jurassic" (as it's been called) monorepo of ~185 code libraries, addressing many of the above topics (plus ~150 examples to illustrate usage). More generally, for the past decade my OSS work has been focused on #TypeScript, #C, #Zig, #WebAssembly, #Clojure, #ClojureScript, #GLSL, #OpenCL, #Forth, #Houdini/#VEX. Earlier on, mainly Java (~15 years, since 1996).

Formative years in the deep end of the #Atari 8bit demoscene (Chip Special Software) & game dev (eg. The Brundles, 1993), B&W dark room lab (since age 10), music production/studio (from 1993-2003), studied media informatics, moved to London initially as web dev, game dev (Shockwave 3D, ActionScript), interaction designer, information architect. Branched out, more varied clients/roles/community for my growing collection of computational design tools, which I've been continously expanding/updating for the past 20+ years, and which have been the backbone of 99% of my work since ~2006 (and which helped countless artists/designers/students/studios/startups). Creator of thi.ng (since 2011), toxiclibs (2006-2013), both large-scale, multi-faceted library collections. Early contributor to Processing (2003-2005, pieces of core graphics API).

Worked on dozens of interactive installations/exhibitions, public spaces & mediafacades (own projects and many collabs, several award winning), large-scale print on-demand projects (>250k unique outputs), was instrumental in creating some of the first generative brand identity systems (incl. cloud infrastructure & asset management pipelines), collaborated with architects, artists, agencies, hardware engineers, had my work shown at major galleries/museums worldwide, taught 60+ workshops at universities, institutions and companies (mainly in EMEA). Was algorithm design lead at Nike's research group for 5 years, working on novel internal design tools, workflows, methods of make, product design (footwear & apparel) and team training. After 23 years in London, my family decided on a lifestyle change and so currently based in the beautiful Allgäu region in Southern Germany.

Do I have anyone in my wider network with skills in programming CUDA, SYCL, and OpenCL?

We want to determine feasibility of migrating CUDA-only code to SYCL (via SYCLomatic?): OpenCV feature detection/extraction modules (SIFT, HAGOG, ORB, AKAZE).

The intent is to upstream all feasible work.

This, hopefully, should stand to benefit everyone instead of being limited to NVIDIA.

Currently in info gathering/people connecting phase, not yet funded & ready to go.

YESSSSS!!!!!

#rusticl is a conformant #opencl 3.0 implementation!!!

special shoutout to:

@gfxstrand who did a lot of the NIR core work getting opencl to be not terrible in Mesa.

Jesse, who worked on this cursed "let's layer opencl on top of d3d12" project, but also contributed a lot of common code I am making use of (src/compiler/clc specifically)

All the iris devs, because that's on Intel 12th gen.

And all the other Mesa contributors