<rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Hacker News: trombonechamp</title><link>https://news.ycombinator.com/user?id=trombonechamp</link><description>Hacker News RSS</description><docs>https://hnrss.org/</docs><generator>hnrss v2.1.1</generator><lastBuildDate>Mon, 07 Sep 2026 18:40:18 +0000</lastBuildDate><atom:link href="https://hnrss.org/user?id=trombonechamp" rel="self" type="application/rss+xml"></atom:link><item><title><![CDATA[New comment by trombonechamp in "Pre-Release of Polars 2.0"]]></title><description><![CDATA[
<p>Is there a reason besides performance that maintain_order=False by default?  I ask because polars is used in many scientific data analysis pipelines, and non-deterministic behaviour is a well-documented source of bugs in scientific computing (e.g. 
<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC6919963/" rel="nofollow">https://pmc.ncbi.nlm.nih.gov/articles/PMC6919963/</a>).  The new default requires users to keep the implementation details of the API in their head while determining whether code is correct or not.  This is tricky with scientific computing because the correct answer is not known in advance, so bugs can slide by and silently give incorrect results.</p>
]]></description><pubDate>Thu, 03 Sep 2026 11:31:36 +0000</pubDate><link>https://news.ycombinator.com/item?id=49548666</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=49548666</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=49548666</guid></item><item><title><![CDATA[New comment by trombonechamp in "The Math of Card Shuffling"]]></title><description><![CDATA[
<p>Here is a bit more realistic model of the riffle shuffle.  These results show that you need between 3 to 8 riffle shuffles, depending on your skill.  Notably, the number of needed shuffles actually does get lower as you get better, i.e., less clumping is better: <a href="http://blog.maxshinnpotential.com/2017/11/05/optimality-in-card-shuffling.html" rel="nofollow">http://blog.maxshinnpotential.com/2017/11/05/optimality-in-c...</a></p>
]]></description><pubDate>Sat, 06 Jul 2024 20:28:03 +0000</pubDate><link>https://news.ycombinator.com/item?id=40892999</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=40892999</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=40892999</guid></item><item><title><![CDATA[New comment by trombonechamp in "Phantom oscillations in principal component analysis"]]></title><description><![CDATA[
<p>This is something a bit different, the effect in the paper comes from the eigenvectors of the data matrix.  I'm no expert on kernel density estimation, but since it is basically just convolution, I would guess the effect you are describing comes from multiplication in Fourier space.</p>
]]></description><pubDate>Tue, 05 Dec 2023 17:17:02 +0000</pubDate><link>https://news.ycombinator.com/item?id=38533798</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=38533798</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=38533798</guid></item><item><title><![CDATA[New comment by trombonechamp in "Phantom oscillations in principal component analysis"]]></title><description><![CDATA[
<p>Sorry, I didn't have funding to pay the open access fees.  The published version is very similar to the preprint: <a href="https://www.biorxiv.org/content/10.1101/2023.06.20.545619v1" rel="nofollow noreferrer">https://www.biorxiv.org/content/10.1101/2023.06.20.545619v1</a>  Alternatively, if you want the full version, PNAS gave me some eprints to share so just email me (link on my site in my profile) and I will send you a copy!<p>Not sure what you mean by "things are stable" in this context, could you elaborate?</p>
]]></description><pubDate>Tue, 05 Dec 2023 14:10:38 +0000</pubDate><link>https://news.ycombinator.com/item?id=38530889</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=38530889</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=38530889</guid></item><item><title><![CDATA[New comment by trombonechamp in "Phantom oscillations in principal component analysis"]]></title><description><![CDATA[
<p>Oh wow, didn't expect to see my paper here.  Happy to answer any questions!</p>
]]></description><pubDate>Tue, 05 Dec 2023 13:47:55 +0000</pubDate><link>https://news.ycombinator.com/item?id=38530611</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=38530611</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=38530611</guid></item><item><title><![CDATA[New comment by trombonechamp in "Researchers analysed novels to reveal six story types"]]></title><description><![CDATA[
<p>Looks like these are just phantom oscillations, a statistical artifact of doing SVD/PCA on smooth data: <a href="https://www.biorxiv.org/content/10.1101/2023.06.20.545619v1" rel="nofollow noreferrer">https://www.biorxiv.org/content/10.1101/2023.06.20.545619v1</a><p>You get the same patterns in music: <a href="https://pure.uva.nl/ws/files/67945245/000016_2_.pdf" rel="nofollow noreferrer">https://pure.uva.nl/ws/files/67945245/000016_2_.pdf</a></p>
]]></description><pubDate>Thu, 09 Nov 2023 17:18:14 +0000</pubDate><link>https://news.ycombinator.com/item?id=38207849</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=38207849</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=38207849</guid></item><item><title><![CDATA[New comment by trombonechamp in "Efficient keyboard layout for English and Spanish"]]></title><description><![CDATA[
<p>Colemak and Rulemak work nicely together.</p>
]]></description><pubDate>Mon, 07 Aug 2023 07:21:50 +0000</pubDate><link>https://news.ycombinator.com/item?id=37031328</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=37031328</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=37031328</guid></item><item><title><![CDATA[New comment by trombonechamp in "MuseScore 4.1 is now available"]]></title><description><![CDATA[
<p>I would be curious to hear more about your dad's opera.</p>
]]></description><pubDate>Thu, 13 Jul 2023 04:41:47 +0000</pubDate><link>https://news.ycombinator.com/item?id=36705090</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=36705090</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=36705090</guid></item><item><title><![CDATA[New comment by trombonechamp in "Gitlab to lay off 7% of staff"]]></title><description><![CDATA[
<p>Is this the mattl I think it is?  If so, hi!</p>
]]></description><pubDate>Thu, 09 Feb 2023 15:04:50 +0000</pubDate><link>https://news.ycombinator.com/item?id=34724998</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=34724998</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=34724998</guid></item><item><title><![CDATA[New comment by trombonechamp in "Ask HN: How do you give back?"]]></title><description><![CDATA[
<p>Do people contact you?</p>
]]></description><pubDate>Sat, 14 Jan 2023 22:48:33 +0000</pubDate><link>https://news.ycombinator.com/item?id=34384904</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=34384904</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=34384904</guid></item><item><title><![CDATA[New comment by trombonechamp in "Ask HN: What's the most important problem in the world? Are you working on it?"]]></title><description><![CDATA[
<p>Maybe a nitpick, but Aaron Swartz was probably quoting Richard Hamming:<p><i>And I started asking, "What are the important problems of your field?" And after a week or so, "What important problems are you working on?" And after some more time I came in one day and said, "If what you are doing is not important, and if you don't think it is going to lead to something important, why are you at Bell Labs working on it?"  ... If you do not work on an important problem, it's unlikely you'll do important work.</i><p>It is the main idea behind his lecture/essay "You and your Research", which is worth reading: <a href="https://www.cs.virginia.edu/~robins/YouAndYourResearch.pdf" rel="nofollow">https://www.cs.virginia.edu/~robins/YouAndYourResearch.pdf</a> or watching:
<a href="https://www.youtube.com/watch?v=a1zDuOPkMSw">https://www.youtube.com/watch?v=a1zDuOPkMSw</a></p>
]]></description><pubDate>Sun, 08 Jan 2023 10:41:15 +0000</pubDate><link>https://news.ycombinator.com/item?id=34297916</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=34297916</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=34297916</guid></item><item><title><![CDATA[New comment by trombonechamp in "The sad story of Heisenberg's doctoral oral exam (1998)"]]></title><description><![CDATA[
<p>I knew it had to be him when you said Sutton and Barto.<p>Yeah, I think we just missed each other since your name sounds familiar.</p>
]]></description><pubDate>Thu, 08 Dec 2022 22:42:45 +0000</pubDate><link>https://news.ycombinator.com/item?id=33914792</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=33914792</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=33914792</guid></item><item><title><![CDATA[New comment by trombonechamp in "The sad story of Heisenberg's doctoral oral exam (1998)"]]></title><description><![CDATA[
<p>Sounds like the classic 4th Floor SHM committee</p>
]]></description><pubDate>Thu, 08 Dec 2022 17:31:14 +0000</pubDate><link>https://news.ycombinator.com/item?id=33910600</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=33910600</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=33910600</guid></item><item><title><![CDATA[New comment by trombonechamp in "People spend too much time on decisions with equally satisfying outcomes"]]></title><description><![CDATA[
<p>I did my PhD on this topic.<p>One classic result from biophysics is that, if all of your decisions have a fixed level of difficulty, then what the author suggests is (mathematically) proven to be suboptimal: if a decision feels more difficult, you actually <i>should</i> spend more time on that decision.  (Keywords to search for: drift diffusion model[2], sequential probability ratio test[3])<p>The technical term for what the author is suggesting one should do (not spending so much time on decisions with equal outcomes) is an "urgency signal", or just "urgency" for short.  If you are using an urgency signal, then you will spend less time on difficult decisions (i.e. ones with near equal outcomes) than you would without an urgency signal, but still more than you would easy decisions.  (For easy decisions, you spend approximately the same amount of time regardless of whether you have an urgency signal.)  In the extreme case, for an infinitely strong urgency signal, you will spend equal time on both easy and difficult decisions.  (See Paul Cisek's work, e.g., [1].)  Conceptually speaking, you need time to detect that the current decision has near-equal outcomes.<p>It was only recently (mathematically) proven that if you have different levels of difficulty in your decisions, it is optimal to use an urgency signal [4,5].  So since most sequences of decisions aren't all equally difficult (as in the study referenced here), in practice, people will use an urgency signal in decision-making.<p>Of course, both the desired accuracy and the urgency signal depend on how the decision is being evaluated: if your goal is to make an accurate decision (e.g. buying a house), then you will have a weaker urgency signal and require more evidence before you make a decision.  By contrast, if you prioritise decision speed, you will show more urgency signal and require less evidence to make a choice.  (The technical term is "speed-accuracy tradeoff".)<p>Current work suggests that when you are making some decision for the first time, you will not use an urgency signal, but as you become an expert at making those decisions, you will gradually develop an urgency signal [6].  This makes sense conceptually: if you know approximately how hard you can expect these decisions to be, you will recognise the situation where they have approximately the same utility and adjust your strategy accordingly.<p>[1] <a href="https://www.jneurosci.org/content/29/37/11560" rel="nofollow">https://www.jneurosci.org/content/29/37/11560</a><p>[2] <a href="https://en.wikipedia.org/wiki/Two-alternative_forced_choice#Drift-diffusion_model" rel="nofollow">https://en.wikipedia.org/wiki/Two-alternative_forced_choice#...</a><p>[3] <a href="https://en.wikipedia.org/wiki/Sequential_probability_ratio_test" rel="nofollow">https://en.wikipedia.org/wiki/Sequential_probability_ratio_t...</a><p>[4] <a href="https://psycnet.apa.org/fulltext/2017-16730-001.pdf" rel="nofollow">https://psycnet.apa.org/fulltext/2017-16730-001.pdf</a><p>[5] <a href="https://link.springer.com/article/10.3758/s13423-017-1340-6" rel="nofollow">https://link.springer.com/article/10.3758/s13423-017-1340-6</a><p>[6] <a href="https://www.sciencedirect.com/science/article/abs/pii/S0010027718303093" rel="nofollow">https://www.sciencedirect.com/science/article/abs/pii/S00100...</a></p>
]]></description><pubDate>Tue, 02 Aug 2022 07:28:47 +0000</pubDate><link>https://news.ycombinator.com/item?id=32316026</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=32316026</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=32316026</guid></item><item><title><![CDATA[New comment by trombonechamp in "How did a woman with a missing temporal lobe become bilingual?"]]></title><description><![CDATA[
<p>It is definitely not true.  One of the many trivial examples is that Betz cells only appear in motor cortex.</p>
]]></description><pubDate>Mon, 04 Jul 2022 08:34:05 +0000</pubDate><link>https://news.ycombinator.com/item?id=31974845</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=31974845</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=31974845</guid></item><item><title><![CDATA[New comment by trombonechamp in "Darktable 4.0"]]></title><description><![CDATA[
<p>The name "Darktable" is a play on Adobe Lightroom, since "lightroom" is a combination of "light table" and "darkroom", both concepts from film photography.</p>
]]></description><pubDate>Sat, 02 Jul 2022 18:52:45 +0000</pubDate><link>https://news.ycombinator.com/item?id=31961377</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=31961377</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=31961377</guid></item><item><title><![CDATA[New comment by trombonechamp in "GSuite legacy users can now get a free personal account, includes Gmail"]]></title><description><![CDATA[
<p>36 hours too late for me - I deleted my 14+ year old GSuite account yesterday morning.  Oh well, Fastmail seems great so far.</p>
]]></description><pubDate>Mon, 16 May 2022 22:26:19 +0000</pubDate><link>https://news.ycombinator.com/item?id=31403856</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=31403856</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=31403856</guid></item><item><title><![CDATA[New comment by trombonechamp in "The Dunning-Kruger Effect Is Autocorrelation"]]></title><description><![CDATA[
<p>That is not what the term "autocorrelation" means.  Autocorrelation is the correlation of a vector/function with a shifted copy of itself.</p>
]]></description><pubDate>Sat, 16 Apr 2022 07:25:27 +0000</pubDate><link>https://news.ycombinator.com/item?id=31050369</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=31050369</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=31050369</guid></item><item><title><![CDATA[New comment by trombonechamp in "Open-source miniature brain microscope"]]></title><description><![CDATA[
<p>FYI, similar technology is already mature and commercially available, e.g., through Inscopix (no affiliation): <a href="https://www.inscopix.com/nvista" rel="nofollow">https://www.inscopix.com/nvista</a>  Looks like the innovation here is getting reliable and lightweight two-photon recordings (allowing more cells and multiplane acquisitions) while the animal is moving around.  Still very cool!<p>And responding to the other commenters, no, this kind of technology is definitely not (and never will be) a toy...</p>
]]></description><pubDate>Wed, 23 Mar 2022 22:11:33 +0000</pubDate><link>https://news.ycombinator.com/item?id=30784164</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=30784164</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=30784164</guid></item><item><title><![CDATA[New comment by trombonechamp in "BLAS-level CPU Performance in 100 Lines of C"]]></title><description><![CDATA[
<p>Once I needed a single LAPACK function (tridiagonal matrix multiplication) in a C Python extension.  I spent an eternity trying to link to LAPACK reliably across platforms until giving up and deciding to implement it myself.<p>My implementation ended up being about 10 lines of code and ran slightly faster (!!!) than the LAPACK function.  (I think this is because LAPACK provided numerical stability for special cases which didn't apply to my use case.)</p>
]]></description><pubDate>Tue, 01 Mar 2022 08:22:32 +0000</pubDate><link>https://news.ycombinator.com/item?id=30511179</link><dc:creator>trombonechamp</dc:creator><comments>https://news.ycombinator.com/item?id=30511179</comments><guid isPermaLink="false">https://news.ycombinator.com/item?id=30511179</guid></item></channel></rss>