11 Nov 2023
Back in April ‘23, I needed a simple solver for function minimization, and
published a basic F# Nelder-Mead solver implementation on NuGet. I
won’t go over the algorithm itself, if you are curious I wrote a post breaking
down how the Nelder-Mead algorithm works a while back.

In a nutshell, the algorithm takes a function, and finds the set of inputs that
produces the smallest output for that function. The algorithm is not foolproof,
but it is very useful, and has the benefit of being fairly simple.

After dog-fooding my library for a bit, I found some rough spots, and decided
it was time to make improvements. As a result, the API has changed a bit -
hopefully for the better! In this post, I’ll go over some of these changes.

## Basic usage

Imagine that you are interested in the following function:

$ f(x,y)=(x-10)^2+(y+5)^2 $

Specifically, you would want to know what values of $(x,y)$ produce the
smallest value for $f$.

This is how you would go about it with Quipu in an F# script:

```
#r "nuget: Quipu, 0.2.0"
open Quipu.NelderMead
let f (x, y) = (x - 10.0) ** 2.0 + (y + 5.0) ** 2.0
NelderMead.minimize f
|> NelderMead.solve
```

This produces the following output:

```
val it: Solution = Optimal (2.467079917e-07, [|9.999611886; -4.999690039|])
```

The solver has found an Optimal solution, for $x=9.999,y=-4.999$, which yields
$f(x,y)=2.467 \times 10^{-7}$, very close to the correct answer, $f(10,-5)=0$.

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29 Oct 2023
In September, I had the great pleasure of attending the
Data Science in F# conference in Berlin. I gave a talk and a workshop on
Linear Programming, and figured I would make the corresponding material
available, in case anybody is interested:

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28 Jun 2023
This is a follow-up to my recent post trying to implement the classic
Conway Game of Life in an MVU style with Avalonia.FuncUI. While I managed
to get a version going pretty easily, the performance was not great. The
visualization ran OK until around 100 x 100 cells, but started to degrade
severely beyond that.

After a bit of work, I am pleased to present an updated version, which runs
through a 200 x 200 cells visualization pretty smoothly:

As a side note, I wanted to point out that the size change is significative.
Increasing the grid size from 100 to 200 means that for every frame, the
number of elements we need to refresh grows from 10,000 to 40,000.

In this post, I will go over what changed between the two versions.

You can find the full code here on GitHub

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17 Jun 2023
A couple of days ago, I came across a toot from Khalid Abuhakmeh,
showcasing a C# + MVVM implementation of the Game of Life on Avalonia. I
have been experimenting with Avalonia funcUI recently, and thought a conversion
would be both a fun week-end exercise, and an interesting way to take a look at
performance.

Long story short, I took a look at his repository as a starting point, and
proceeded to rewrite it in an Elmish style, shamelessly lifting the core from
his code. The good news is, it did not take a lot of time to get it running,
the less good news is, my version has clear performance issues.

In this post, I will go over how I approached it so far, and where I *think*
the performance issues might be coming from. In a later post, I’ll try to see
if I can fix these. As the French saying goes, “A chaque jour suffit sa peine”.

You can find the full code here on GitHub

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29 May 2023
In the recent weeks, I came across a use case which sounded like a good fit for
a desktop application, which got me curious about the state of affairs for .NET
desktop clients these days. And, as I was looking into this, I quickly came
across Avalonia, and specifically Avalonia.FuncUI. Cross platform
XAML apps, using F# and the Elmish loop? My curiosity was piqued, and I figured
it was worth giving it a try.

In this post, I will go over my first steps trying the library out. My
ambitions are limited: first, how hard is it to get something running? Then,
how hard is it to take an existing Avalonia library (in this case, the
charting library OxyPlot), and bolt it into an Elmish style Avalonia app?

You can find the full code here on GitHub

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