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Category: Misc Languages

A Primer on Stan

Published 2023-02-10 by Kevin Feasel

Jack Kennedy explains the concepts of Stan and JAGS:

You may have used a probabilistic programming language (PPL) in the past, such as BUGS, to perform Bayesian inference. You’ve heard about Stan and want to learn a little more. Or maybe you’re about to step into the Bayesian paradigm and don’t know where to start. You want to know whether you should make the switch from JAGS to Stan, or you’ve used neither of JAGS or Stan and want to know which will suit you best. This post will focus solely on the differences between JAGS and Stan as I have experience with both of them, but there are many more PPLs out there. For example, I have never used Bean Machine, but of all the PPLs, it certainly takes the crown for best name.

Stan has been on my to-learn list for a while and I did successfully get one of my employees (a rassa-frassin’ frequentist) to use and enjoy the power of Bayesian analysis. One of these days, I’ll have to get back to it.

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Simplified Syntax for Scala 3

Published 2023-02-01 by Kevin Feasel

Anshika Agrawal shows a few examples of how Scala 3 is a bit easier to pick up than Scala 2:

Scala 3 is a remodel/refit for the scala language. It attracts developers due to its improved features such as simpler syntax, better type inference, improved error messages, and enhanced support for functional programming. In this article, we will compare the syntactical enhancement of Scala 2 & Scala 3. How indentation will help developers to write code efficiently and effortlessly.

Click through for some examples. On the whole, these are small but welcome changes in eliminating unnecessary code cruft.

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Object Deconstruction in C#

Published 2023-01-19 by Kevin Feasel

Patrick Smacchia shows off a feature in C#:

C# 7.0 introduced the deconstruction syntax. It allows developers to extract in a single expression, properties of an object or elements of a tuple and then to assign them to distinct variables . Here is a small program candidate to be simplified with deconstruction:

I enjoy (more than I should) being able to say “C# got this from F#.” Object deconstruction is quite useful and it’s good to see that the C# syntax is close to what we get in F# or Python.

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Running ML.NET in F#

Published 2022-12-30 by Kevin Feasel

Matt Eland builds a notebook:

In this article I’ll outline a simple pipeline that trains a regression machine learning model and saves it to a file for use later on. We’ll look at how to load the model using F# and use it to generate new predictions for new data points.

To round things out, I’ll be showing you how to do this all in a Polyglot Notebook, though you can skim over this aspect of the experiment as almost all of the code will work just fine in a normal .fs file outside of Polyglot Notebooks.

At the end, Matt mentions that the F# code looks a whole lot like C# code and that’s my biggest problem with the library: it forces you into writing C#-style code.

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Join Types in Spark SQL

Published 2022-12-29 by Kevin Feasel

Rituraj Khare makes some connections:

In Apache Spark, we can use the following types of joins in SQL:

Inner join: An inner join in Apache Spark is a type of join that returns only the rows that match a given predicate in both tables. To perform an inner join in Spark using Scala, we can use the join method on a DataFrame.

The set of options is the same as you’d see in a relational database: inner, left outer, right outer, full outer, and cross. The examples here are in Scala, though would apply just as easily to PySpark and, of course, writing classic SQL statements.

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Closures in Scala (and All FP Languages)

Published 2022-12-28 by Kevin Feasel

Pallav Gupta explains what a closure is:

Objects are more flexible for certain use cases because they carry both data members and member functions, whereas a function does not have data members.

So if there is a requirement to pass data members along with functions, How will we achieve it in functional programming ?

The answer is yes, we can achieve it using a closure and a free variable.

Read on for an example.

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Creating an Azure Function for Cosmos DB

Published 2022-12-22 by Kevin Feasel

Hasan Savran needs a function:

Azure Cosmos DB’s Change Feed feature triggers an event for Inserts and Updates in a collection. The easiest way to handle these events is, by executing an Azure Function. In this post, I will focus on creating an Azure Function for Azure Cosmos DB by using VsCode.

Read on for step-by-step instructions. The wizard for creating Function apps and then Azure Functions is pretty well-designed.

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Advent of Code in Postgres

Published 2022-12-20 by Kevin Feasel

Ryan Booz has some videos for us:

As I go, I’ll upload my finished code to my repo and (hopefully) record a video for each day explaining my approach. I’ve finished through day 8 (as of December 14, 2022), but haven’t finished all of the videos yet. Again, my goal is to enjoy the challenge and learn, not try to be the first one done or get on a leaderboard somewhere. This also means it will probably take into January 2023 to finish the puzzles and record videos.

Enough explanation! Let’s talk about the first five puzzles, including links to the videos.

Read on for days 1-5 of the challenge.

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Building Retry Logic for Database Calls

Published 2022-12-19 by Kevin Feasel

Jose Manuel Jurado Diaz tries and tries again:

Today, I worked on a case that our customer faced an execution command timeout “Msg -2, Level 11, State 0, Line 0 – Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding“

As this business process is running over the night and they need to ensure that the execution will be completed, they asked if there is possible to implement an Execution Retry Logic. 

In the similar way that we have for Retry-Logic for Transient Failure We could implement a similar mechanism to retry the operation, the only thing that we need is to change the commandTimeout parameter, for example, in .NET. 

Click through for an example of how you can implement this in code. I’d also recommend Polly, which is a library explicitly built for these sorts of issues.

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