Feature/colpiv qr in nalgebra lapack (#1551)

* start implementation of col piv qr with lapack

* implement basic decomposition

* keep on keeping on

* add triangular solve API

* add permutation tests

* start with rank estimation strategies

* better rank calculation algorithms

* implement owned solver API

* add test for solving

* fix error in lapack diag character conversion

* fix test for equality

* tests for rank deficient problems

* add some comments

* remove some rambling comments

* add more tests, permutations are inverted I think

* fix tests for qr decomposition

* refactor permutation interface to require less allocations

* add comments

* add test helper for max diagonal matrix

* add tests for q matrix

* refactor q multiplication interface

* change q multiplication interface, more changes incoming

* fix dimensions for q multiplication and add test

* remove some superfluous trait bounds

* remove tests for underdetermined rank with qr

* stricter assertions, fix compiler warnings

* factor our error, fix warnings

* start with adding proptest module for colpiv qr

* Qr->QR naming consistent with nalgebra

* bump lapack and lapack-src versions

* fmt

* add basic proptests for qr decomposition

* fmt

* test Q^T Q = Id

* fix proptest compile

* change col permutation logic and test normal equations for matrix solve test

* fix borked permutation logic'

* dynamic linear system proptests

* move strategy back to my module

* remove unused imports

* add documentation, change solver signature slightly

* fix comments, replace unwrap error handling

* make col piv qr public so that it can be used from other crates

* properly expose the unsafety in the lapack backend

* split changelogs as discussed with sebcrozet

* replace unsafe traits with sealed traits

* remove outdated links

* documentation overhaul, lapack-src updates, better selection of lapack features

* add extern crate back, fix num accuracy in tests for mkl

* fix wrong sign in complex conjugate (a + ib)* = a - ib

* migrate complex eigen tests to use proptest for more exhaustive testing

* update changelog

* update changelog again

* fmt changes in docs

Author: geo-ant

CHANGELOG.md

@@ -5,6 +5,9 @@ documented here.
 
 This project adheres to [Semantic Versioning](https://semver.org/).
 
+**nalgebra-lapack change log** is found [here](https://github.com/dimforge/nalgebra/blob/main/nalgebra-lapack/CHANGELOG.md)
+starting with `nalgebra-lapack` version `0.27.0`.
+
 ## [0.34.1] (20 Sept. 2025)
 
 ### Added

nalgebra-lapack/CHANGELOG.md

@@ -1,5 +1,18 @@
 # Change Log
 
+For the **changes between versions 0.4.0 and 0.27.0** see the main
+[nalgebra change log](https://github.com/dimforge/nalgebra/blob/main/CHANGELOG.md).
+
+## Unreleased
+
+* bugfixes in Schur decomposition
+* bugfixes in LU decomposition
+* fix failing tests for Cholesky decomposition
+* fix compilation with `serde-serialize` feature enabled
+* add column-pivoting QR decomposition and solver
+* fix logic error in calculation of complex eigenvalues in eigen-decomposition.
+* change the feature flags for choosing the lapack backend, update docs accordingly
+
 ## [0.4.0] - 2016-09-07
 
 * Made all traits use associated types for their output type parameters. This

nalgebra-lapack/Cargo.toml

@@ -4,7 +4,6 @@ version = "0.26.0"
 authors = ["Sébastien Crozet <developer@crozet.re>", "Andrew Straw <strawman@astraw.com>"]
 
 description = "Matrix decompositions using nalgebra matrices and Lapack bindings."
-documentation = "https://www.nalgebra.rs/docs"
 homepage = "https://nalgebra.rs"
 repository = "https://github.com/dimforge/nalgebra"
 readme = "../README.md"
@@ -17,26 +16,32 @@ edition = "2024"
 maintenance = { status = "actively-developed" }
 
 [features]
+default = ["lapack-netlib"]
 serde-serialize = ["serde", "nalgebra/serde-serialize"]
 proptest-support = ["nalgebra/proptest-support"]
 arbitrary = ["nalgebra/arbitrary"]
 slow-tests = []
 
 # For BLAS/LAPACK
-default = ["netlib"]
-openblas = ["lapack-src/openblas"]
-netlib = ["lapack-src/netlib"]
-accelerate = ["lapack-src/accelerate"]
-intel-mkl = ["lapack-src/intel-mkl"]
+lapack-openblas = ["lapack-src/openblas"]
+lapack-netlib = ["lapack-src/netlib"]
+lapack-accelerate = ["lapack-src/accelerate"]
+lapack-mkl = ["lapack-mkl-static-seq"]
+lapack-mkl-static-seq = ["lapack-src/intel-mkl-static-sequential"]
+lapack-mkl-static-par = ["lapack-src/intel-mkl-static-parallel"]
+lapack-mkl-dynamic-seq = ["lapack-src/intel-mkl-dynamic-sequential"]
+lapack-mkl-dynamic-par = ["lapack-src/intel-mkl-dynamic-parallel"]
+lapack-custom = []
 
 [dependencies]
 nalgebra = { version = "0.34", path = ".." }
 num-traits = "0.2"
 num-complex = { version = "0.4", default-features = false }
 simba = "0.9"
 serde = { version = "1.0", features = ["derive"], optional = true }
-lapack = { version = "0.19", default-features = false }
-lapack-src = { version = "0.8", default-features = false }
+lapack = { version = "0.20", default-features = false }
+lapack-src = { version = "0.13", optional = true}
+thiserror = "1.0"
 # clippy = "*"
 
 [dev-dependencies]
@@ -45,4 +50,3 @@ proptest = { version = "1", default-features = false, features = ["std"] }
 quickcheck = "1"
 approx = "0.5"
 rand = "0.8"
-