celrod

37 ms·

331.
by celrod 8y ago
Relevant xkcd: https://what-if.xkcd.com/13/
332.
by celrod 8y ago
I've often brought up GPUs while talking to folks, because they're interesting and offer a world of potential. I have two computers, one with a Ryzen 1950X, and the other an i9 7900X. Both CPUs cost about the same, but the i9 (wit
333.
by celrod 8y ago
I think icc's biggest advantage is automatically translating appropriate calls into calls to those performance libraries and linking them. If you manually make calls in GCC, I bet you'd see similar performance much of the time. ic
334.
by celrod 8y ago
Recent LLVM and GCC make good use of avx512. Although for GCC, you need to use the option -mprefervectorwidth=512. Unfortunately benchmarks on websites like Phoronix do not make use of them. But when it comes to numerical computing, it is a
335.
by celrod 8y ago
"One of the foundational problems with the soft/social sciences is that many of its practitioners have such weak analytical thinking skills (Note below)" Andrew Gelman argued that a fundamental problem with peer review is tha
336.
by celrod 8y ago
Big disclaimer: my experiences are limited, and compiler comparisons are going to be highly variable, depending on the particular code bases. That said, I have a statistics model that has to be fit thousands (millions?) of times. As a basel
337.
by celrod 8y ago
I think it's worth pointing out that someone who knows way more about Julia internals than I do (yuyichao) said this comment is wrong on several points on the [Julia discourse]( https://discourse.julialang.org/t/for
338.
by celrod 8y ago
Languages like C(++), Rust, and Julia have vector intrinsics that are unfortunately lacking in Fortran. Is there a way to wrap [SLEEF]( https://github.com/shibatch/sleef ) in Fortran? While writing fast code in Fortran i
339.
by celrod 8y ago
Actually, almost all Fortran code says "implicit none".
340.
by celrod 8y ago
I found this article fascinating: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.130... The jist is, people are extremely bad at basic logic. Unless it's really in their best interest within the context
341.
by celrod 8y ago
For reference, here is a link to the Phoronix Windows vs Linux on the 2990WX article: https://www.phoronix.com/scan.php?page=article&item=2990wx-l...
342.
by celrod 8y ago
Most of what I do is floating point operations, so I'll see >100% performance gains with the avx boost. I will upgrade.
343.
by celrod 8y ago
I think it is Juno (the Julia package for Atom)'s fault. Atom is fine on its own, as is the Julia REPL after compilation. I just looked through Julia's settings tab in Atom, and saw the option "Fallback Renderer" with th
344.
by celrod 8y ago
Over on Phoronix, folks seem to have been much more excited about the Talos II by Raptor Computing Systems. They come with IBM POWER9 CPUs. "The Talos™ II mainboard is the first modern (post-2013), owner-controllable, workstation- and
345.
by celrod 8y ago
It uses reticulate for REPL support, and has basic Python completions and snippets. However, it doesn't seem to complete variable names. Eg, if I defined "foobar", it won't let me tab-complete that later when I start typ
346.
by celrod 8y ago
RStudio is also my favorite editor. All my work is data science / stats related, where I like the workflow of writing/modifying code in a .R (or .py) file, and being able to quickly experiment by running chunks in a REPL with Ctrl
347.
by celrod 8y ago
Simple test, `memcopy.c`: void memcopy(double* restrict a, double* restrict b, long N){ for (long n; n < N; n++){ a[n] = b[n]; } } You can check assembly with: gcc -march=skylake-avx512 -O2 -ftree-vectorize -mp
348.
by celrod 8y ago
Yes. My code is mostly AVX, so regardless of down-clocking I see substantial performance boosts. But I've found getting into GPU computing extremely difficult. Admittedly, part of that may be having bought an AMD Vega graphics card ins
349.
by celrod 8y ago
Much of what I do is vectorized, so the more fma units and the side wider, the faster. So avx512 > avx2 with two 256 bit units > avx2 with two 128 bit units. But my work (statistics) seems poorly represented in benchmarks and the comm
350.
by celrod 8y ago
The article discusses an "oligarch" model of planet formation, where there are roughly early sized and spaced oligarchs early on in planet development. Because our solar system didn't end up with the "peas in a pod"
351.
by celrod 8y ago
Probability Theory the Logic of Science is an excellent textbook on math and theory. Note the title even references cultus' point. Unfortunately it predates many of the modern developments in methods / computation, but if you want
352.
by celrod 8y ago
Are there any good guides or tutorials? I've found GPUs difficult, in part because I don't really know where to start. FWIW, I have an AMD GPU with ROCm. HIP it's a lot like CUDA, so NVidea-focused tutorials ought to be fine.
353.
by celrod 8y ago
I'm saying there is a reason to favor a CPU with avx512. The reason may not apply to you / your work flow. If your number crunching is just neural networks on your GPU, then the CPU doesn't matter. But there's probably a
354.
by celrod 8y ago
The Xeon-W 2175 has avx-512. Threadrippers cannot compete in numbering work relative to price point on well optimized code. sgemm on 5000x5000 matrices takes about 600ms on a Threadrippers 1950x, but only around 150ms on the comparatively p
355.
by celrod 8y ago
Because Fortran was listed as x.xxx, I figured I'd try it. Taking the minimum of 100 runs of gcc/gfortran, 200 runs of g++, and 4 runs of Julia 1.1-dev: gcc: 3.4866 g++: 3.4428 gfortran: 3.4953 Julia: 8.0378 I was doing other thin
356.
by celrod 8y ago
For those interested in Causal Inference, here is Judea Pearl's fairly accessible intro "An Introduction to Causal Inference": http://ftp.cs.ucla.edu/pub/stat_ser/r354-corrected-reprint.p...
357.
by celrod 8y ago
This reminds me of functional data analysis, where they favor spline models (avoids Runge's phenomenon and leverage-point issues), and also heavily emphasize thinking about and modeling derivatives. The name "functional" also
358.
by celrod 8y ago
If you want another example, I saw this a couple days ago: "Also exciting - we only have 27k signatures right now, and removing all the ones taking row vectors reduces that substantially to under 10k. That seems doable pretty easily, a
359.
by celrod 8y ago
The problem isn't just whether or not it uses SIMD instructions, but avoiding redundant and unnecessary `vmov` instructions. For example, I filed a bug here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86625 beca
360.
by celrod 8y ago
Steven G. Johnson, who wrote much of FFTW in OCaml, is now a major Julia contributor! Or OCaml and C? Wikipedia isn't especially clear on that.

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