@kyonifer yeah... I think that's why I never fully abandoned ojAlgo for Koma because I found its pure Java implementation something to learn from. It's been around since 1997 but Anders has dogfooded it heavily for his work since, and therefore kept it updated and overhauled as needed. It's always been in the back of my mind to create a pure Kotlin implementation inspired by ojAlgo (no C-based BLAS backends). It has robust support for rational number matrices and complex numbers. And yeah it's a little hard on the eyes to look at the implementation, but only because Anders optimized the hell out of it.