dimhold.by

Writing

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October 4, 2026

Haiku 4.5 found the key 243 times of 245 in prompts up to 96 thousand tokens. For a key that was not there, it returned a value 12 times of 20.

I had the Lost in the Middle chart in my head and never checked it on the model I use every day. On a key and value lookup haiku 4.5 found the key 243 times of 245 across 11 depths in prompts up to about 96 thousand tokens, with no dip in the middle. The degradation was somewhere else: asked for a key that was not in the object, it began returning values instead of NOT FOUND after 2000 pairs and at 6000 pairs returned a value 12 times of 20.

23 min read

language models reliability

October 3, 2026

A plain classifier named the key by its sound 99 times in 100. Trained on the silence between presses, it still named it 39 times

I took the public keystroke datasets behind the 95% headline and a plain logistic regression. It named the key 92 to 99 times in 100, but the same model trained on the silence between presses still named it up to 39 times in 100. Every key in these sets is its own file. On passwords, where the file cannot help, it got 77 of 100. Another recording of the same MacBook brought it down to 5 or 6%.

19 min read

machine learning open data

September 27, 2026

Please costs 24 dollars per million calls, which is nothing. Just the answer cost me 32.5 points of accuracy.

A year ago I stripped every please and thank you out of my prompt templates because of a joke Sam Altman made about electricity. I never checked what I saved. 20171 calls later the polite wrapper costs 24 dollars per million requests on sonnet and moves the answer no more than a control wrapper with no social word in it. The wrapper that did move things was the one telling the model how much to write: Just the answer takes haiku on GSM8K from 88.5 percent down to 56.0.

17 min read

language models statistics performance

September 26, 2026

The Big Dipper in 100,000 years. 5 of its 7 stars keep the shape within 0.17 degrees

I wanted an animation of the Big Dipper from 100,000 years ago to 100,000 years ahead and expected 7 stars going in 7 directions. Gaia DR3 does not have Dubhe at all, so the data is Hipparcos 2007 with radial velocities from SIMBAD, straight lines in 3D. A fit on the 5 middle stars leaves them within 0.17 degrees after 100,000 years, while Dubhe is off by 6.9 and Alkaid by 7.3. The whole falling apart is the 2 end stars.

10 min read

open data numbers

September 20, 2026

The grid hum dated 111 of 128 recordings to within 5 seconds. One reference file holds the same hour 7 times

I took the 130 phone and voice recorder recordings of the open Wuhan dataset and a plain search: find the grid hum, follow it second by second, slide the curve along the day. At 50 Hz it found 4 of 130, at 100 Hz the same search found 116. With a harmonic chosen without looking at the answer it found 113. 2 of them sit in an hour that one reference file holds 7 times, so only 111 of 128 can be checked. Then the same errors went into a month of the British grid.

19 min read

time open data

September 14, 2026

My README said this benchmark needs a 2× difference to see anything. Given a known delay, it saw 3%

In the README of my preview benchmark I wrote that the harness could not tell apart 2 strategies within 2× of each other. I gave it a busy wait of known size on PostgreSQL 16.14 and OpenJDK 21: 10 JVMs per delay, 300 pairs each. Paired inside one JVM it saw 25 µs on 800 (3%) in 10 of 10 JVMs, while the JVM medians differed by a third. Comparing 2 separate runs got the sign of a 100 µs delay right in 68 of 90 cases and the blocked order of the first version called a 50 µs slower block faster in 7 of 10.

11 min read

performance statistics

September 7, 2026

15 years after Simple Made Easy: 0 of my 102 local variables were final in 2013 and 91.6% of the code I keep is const now. I chose neither

In may 2013 I started a repository to translate a Rich Hickey talk into Russian. It is still at 0%. That same week I committed synchronized collections to a Java server. I rebuilt that shape and measured it. The commit did not move the failure rate at all. Then I ran the checklist from Simple Made Easy over my own code. 0 of my 102 local variables were final in 2013 and 91.6% of the code I keep is const now. I chose neither.

11 min read

code quality types