Update bibtex for Lanczos paper and mention LstSq paper in readme (#257)

* Update bibtex for Lanczos paper and mention LstSq paper in readme

* Preserve previous bibtex keys

Author: pnkraemer

README.md

@@ -107,10 +107,25 @@ We would appreciate it if you cited the paper as follows:
 
 ```bibtex
 @article{kraemer2024gradients,
-    title={Gradients of functions of large matrices},
-    author={Kr\"amer, Nicholas and Moreno-Mu\~noz, Pablo and Roy, Hrittik and Hauberg, S{\o}ren},
-    journal={arXiv preprint arXiv:2405.17277},
-    year={2024}
+  title={Gradients of functions of large matrices},
+  author={Kr{\"a}mer, Nicholas and Moreno-Mu{\~n}oz, Pablo and Roy, Hrittik and Hauberg, S{\o}ren},
+  journal={Advances in Neural Information Processing Systems},
+  volume={37},
+  pages={49484--49518},
+  year={2024}
+}
+```
+
+If you are using Matfree's differentiable LSMR implementation, then you
+are using the algorithm from [this paper](https://arxiv.org/abs/2510.19634).
+We would appreciate it if you cited the paper as follows:
+
+```bibtex
+@article{roy2025matrix,
+    title={Matrix-Free Least Squares Solvers: Values, Gradients, and What to Do With Them},
+    author={Roy, Hrittik and Hauberg, S{\\o}ren and Kr{\"a}mer, Nicholas},
+    journal={arXiv preprint arXiv:2510.19634},
+    year={2025}
 }
 ```
 

matfree/decomp.py

@@ -56,9 +56,10 @@ def tridiag_sym(
         ```bibtex
         @article{kraemer2024gradients,
             title={Gradients of functions of large matrices},
-            author={Kr\"amer, Nicholas and Moreno-Mu\~noz, Pablo and
-            Roy, Hrittik and Hauberg, S{\o}ren},
-            journal={arXiv preprint arXiv:2405.17277},
+            author={Kr{\"a}mer, Nicholas and Moreno-Mu{\~n}oz, Pablo and Roy, Hrittik and Hauberg, S{\o}ren},
+            journal={Advances in Neural Information Processing Systems},
+            volume={37},
+            pages={49484--49518},
             year={2024}
         }
         ```

matfree/lstsq.py

@@ -33,15 +33,15 @@ def lsmr(
     Setting `custom_vjp` to `True` implies using the low-memory
     gradients of matrix-free least squares,
     according to what has been proposed by Roy et al. (2025).
+    [Here](https://arxiv.org/abs/2510.19634) is a link to the preprint.
     These gradients are exact, so there is little reason not to use them.
     If you use this configuration, please consider
     citing Roy et al. (2025; bibtex below).
 
     ??? note "BibTex for Roy et al. (2025)"
         ```bibtex
         @article{roy2025matrix,
-        title={Matrix-Free Least Squares Solvers:
-        Values, Gradients, and What to Do With Them},
+        title={Matrix-Free Least Squares Solvers: Values, Gradients, and What to Do With Them},
         author={Roy, Hrittik and Hauberg, S{\\o}ren and Kr{\"a}mer, Nicholas},
         journal={arXiv preprint arXiv:2510.19634},
         year={2025}

pyproject.toml

@@ -117,6 +117,8 @@ ignore = [
     "D213",
     # zip(..., strict=True/False) is not supported on Python < 3.10
     "B905",
+    # Disable line-too-long because it is handled by formatter (and we allow docstrings to contain long lines)
+    "E501",
 ]
 
 [tool.ruff.format]