This article is reproduced from “Caiyun Weather Geo Query Optimization: The nearest N points” Let’s start from a real-world scenario: How to find the K nearest national observation stations to the 768 Creative Industry Park in Haidian District, Beijing? The simplest approach is to iterate over all candidate stations, compute the distance between each station and the 768 park, and then pick the K smallest distances. The code is straightforward. But the problem is it is slow. ...

When dealing with large amounts of scattered data, sometimes we need to provide a read-only query API to visualize on a map. When the amount of data is too large, say millions, it is not appropriate to return it all to the front end for processing on the browser. Some aggregation should be completed within the back-end service to return the aggregated search to the front end. Here’s how to do this with the MongoDB + tile index in Go. ...

I write a package named aqi. Install: 1 go install github.com/ringsaturn/aqi For China’s HJ633-2012 standar: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 package main import ( "fmt" "github.com/ringsaturn/aqi" "github.com/ringsaturn/aqi/mep" ) func main() { algo := &mep.Algo{} inputs := []*aqi.Var{ { P: aqi.Pollutant_PM2_5_1H, Value: 16, }, { P: aqi.Pollutant_PM10_1H, Value: 88, }, { P: aqi.Pollutant_CO_1H, Value: 0.2, }, { P: aqi.Pollutant_SO2_1H, Value: 3, }, { P: aqi.Pollutant_NO2_1H, Value: 11, }, { P: aqi.Pollutant_O3_1H, Value: 75, }, } aqi, primaryPollutant, err := algo.Calc(inputs...) if err != nil { panic(err) } levelDesc, err := algo.AQIToDesc(aqi) if err != nil { panic(err) } fmt.Printf("aqi=%v as level=%v with primary pollutant as %v\n", aqi, levelDesc, primaryPollutant) } Output: ...

Code copy&paste from Ataias Pereira Reis’s PR adityatelange/hugo-PaperMod#140 with some modifed on toggle option. Creat two files under layouts/partials/. Create math.html: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 <script> MathJax = { tex: { inlineMath: [["$", "$"], ["\\(", "\\)"]], displayMath: [["$$", "$$"]], processEscapes: true, processEnvironments: true, tags: "ams", }, options: { skipHtmlTags: [ "script", "noscript", "style", "textarea", "pre", ], }, startup: { ready: () => { MathJax.startup.defaultReady(); // Fix <code> tags after MathJax finishes running const all = MathJax.typesetPromise(); all.then(() => { document.querySelectorAll(".MathJax").forEach( (el) => { el.parentNode.className += " has-jax"; }, ); }); }, }, }; </script> <script id="MathJax-script" async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/3.2.2/es5/tex-mml-chtml.js" ></script> Create extend_head.html: ...