Just spent half an hour chasing an error which resulted in my code giving answers that are a fraction of an arcsecond off. Turns out that, for some reason, exponentising reals can cause loss of precision in Fortran 🤷♂️
Once again Wolfram Alpha proves its incredible usefulness.
I love this piece about #lowlevel #programming (which includes a shameless plug for #fortran, something I had not realized before)
New #Fortran post: "Enumeration, part 3" https://matthiasnoback.nl/2025/06/fortran-enumeration-part-3/
It's surprising how much there is to explore about enumeration types, but here we are with the final part: we further improve the design by making log level an abstract type, and all the concrete levels subtypes.
New #Fortran post: "Enumeration, part 2" https://matthiasnoback.nl/2025/06/fortran-enumeration-part-2/
We increase type safety by narrowing the integer level argument to a derived type argument. By introducing a factory type for log levels we are able to separate responsibilities. Finally we allow level comparisons using operator overloading.
New #Fortran post: "Fortran: Enumeration, part 1" https://matthiasnoback.nl/2025/06/fortran-enumeration-part-1/
We are refactoring the integer parameters for the various log levels that we want to support. We want to accomplish type-safety and ease-of-use (pun intended).
Things I learned yesterday and today.
Python doesn't understand quadruple-precision real numbers. f2py will happily compile Fortran code containing real(16)s into a form that Python can talk to, but Python will segfault as soon as it receives one of those real(16)s.
Also, Fortran's built-in fraction function doesn't do what I thought it did.
New #Fortran post: "Module Design" https://matthiasnoback.nl/2025/06/fortran-module-design/
We look into splitting an existing module into smaller modules. We then put a façade module in front of the smaller modules, so users only have to deal with a simple programming interface. Finally we fix compilation cascade issues by introducing the concept of a submodule.
New #Fortran post: Service Composition, part 2: Decoration https://matthiasnoback.nl/2025/06/fortran-service-composition-decoration/
In this post we explore another way of composing abstractions, which is called decoration. We prefix existing log messages with a timestamp and implement optional delegation based on a configured log level.
#Fortran has joined the modern world: it has its own conference, #FortranCon.
📣 Back to the Fortran Future 2 📣
This satellite event takes place 8th September 2025 adjacent to RSECon25 (9-11th September 2025) at the University of Warwick.
Its free to attend, so if you have an interest in Scientific Fortran please consider joining us.
New #Fortran post "Fortran: Service Composition, part 1: Aggregation" https://matthiasnoback.nl/2025/06/fortran-service-composition-aggregation/
We are ready to build more features into the logging library, using different styles of composition. First we look at aggregation.
New #Fortran post: "Abstract Types and Deferred Procedures" https://matthiasnoback.nl/2025/06/fortran-abstract-types-and-deferred-procedures/
We define an abstract type with deferred procedures (in OO language: an interface) for the file logger. Introducing an abstract factory allows clients to decouple from specific service types and shows us how polymorphism works.
New #Fortran post: "Modeling Services as Derived Types" https://matthiasnoback.nl/2025/06/fortran-modeling-services-as-derived-types/
Derived types are good for "data objects", but they can also be used for "service objects". We look at a safe refactoring from module state and subroutines to a derived type with a data component and a type-bound procedure.
@muzej I used this as my first programming manual: https://plus.cobiss.net/cobiss/si/sl/bib/16922 #fortran
Hold on, f2py CAN make Fortran functions comprehensible to Python‽ I DON'T have to use subroutines‽ Fortran syntax is just incredibly FUSSY‽
New #Fortran article: "Private Data Components and Custom Constructors" https://matthiasnoback.nl/2025/06/fortran-private-data-components-and-custom-constructors/
We make the data inside the derived type private (encapsulation), offer alternative ways for creating new instances (factory functions), and expose these alternatives as an abstract function.
📘 FORTRAN IV Manual (1982), adapted by Rafko Adrinek and published by Iskra Delta! 💖 #FORTRAN was the first widely adopted “standard” programming language, especially popular during the 1960s and 70s — the punch card era. 💾 Back then, it powered massive mainframes, and its legacy still lives on today in modern supercomputer programming! 🚀
New #Fortran post: "Type-bound Procedures" https://matthiasnoback.nl/2025/06/fortran-type-bound-procedures/ These are the equivalent of class methods, but can surprisingly still be used as regular functions.
