Release date: 11/11/22.
This material is based upon work supported by the National Science Foundation and the Department of Energy.
LAPACK is a software package provided by Univ. of Tennessee, Univ. of California, Berkeley, Univ. of Colorado Denver and NAG Ltd..
1. Support and questions:
2. LAPACK 3.11.0: What’s new

Download: lapack3.11.0.tar.gz
This is a major release and also addressing multiple bug fixes.
2.1. Normwise criterion for infinite eigenvalues in the QZ algorithm by @thijssteel
The normwise criterion is more robust at detecting infinite eigenvalues than the elementwise criterion (PR #698). See also https://arxiv.org/abs/2208.02057.
2.2 level3 BLAS solvers for the triangular system and triangular Sylvester equations by @angsch
The triangular Sylvester equation has been recognized to be prone to overflow. For that purpose, *TRSYL
utilizes a scaling factor to represent the solution as (s^{1} X)
and solve the scaled equation AX + XB = s C
. Due to the scaling factor, there is some flexibility in the representation of the solution. The proposed level3 BLAS version computes the scaling factors based on the upper bounds of blocks to enable level3 BLAS. The scaling is typically slightly more aggressive so that an alternatively scaled final solution is computed. This is no problem as long as the scaling factor does not get flushed to zero (PR #651). The same upper bound calculation was used to write the level3 BLAS solver for the triangular system, *LATRS3
.
2.3 Givens rotations generated with less accumulation error by @weslleyspereira
New algorithms for computing Givens rotations in complex arithmetic that reduce the accumulation errors for computing each of the outputs, c, s, r
. The new algorithms are, on average, more accurate than both the algorithms from LAPACK 3.9.1 and LAPACK 3.10.0 (PR #631). See also https://arxiv.org/abs/2211.04010.
2.4 Faster algorithms for Least Squares by @scr2016
The new algorithms, *GELST
, are similar to *GELS
. *GELST
avoids computing triangular blocks twice as in *GELS
, which means *GELST
runs faster (PR #739).
2.5 Improvements on the building system and the Continuous Testing framework

Regression test for illegal modification of Y in
*GEMV
by @matcross in PR #622. 
Test the Fortran intrinsic ABS and complex divisions and report failures during build by @weslleyspereira in PR #623.

Appveyor is working in the Continuous Testing once more by @martinfrbg in PR #627.

More tests and fixes for type mismatches by @angsch in PR #675.

Fix an outofbounds write in the tests by @angsch in PR #685.

Adding support for NAG Fortran compiler (nagfor) by @ACSimon33 in PR #686.

Fix time check flag propagation and default value by @ACSimon33 in PR #696.

Fixed format warnings in 64 bit integer builds by @ACSimon33 in PR #700.

Explicit type casts and more rigorous CI by @weslleyspereira in PR #703.

Fix type mismatches in function calls of testing code by @mjacobse in PR #706.

Fix lower triangular band matrix generation by @angsch in PR #728.
2.6 Other improvements

Improves the computation of norms in
{S,D}ORBDB6
and{C,Z}UNBDB6
by @Christoph Conrads in PR #647. 
Uses a Newton step to compute the initial guess for
ETA
in{S,D}LAED4
to reduce the number of iterations by @weslleyspereira in PR #655. 
Return immediately when scaling with one by @angsch in PR #674.

Rearrange the application of the Householder reflectors in
*LAQR5
, which lowers the instruction count when FMA is available by @angsch in PR #681. 
Set SCALE early for robust triangular solvers by @angsch in PR #712.

Add
{C,Z}ROTG
,{CS,ZD}ROT
,{S,D}CABS1
to CBLAS by @angsch in PR #721. 
Add
*LANGB
to LAPACKE by @ACSimon33 in PR #725. 
NaN check for trapezoidal matrices on LAPACKE by @ACSimon33 in PR #738 and PR #742.
2.7 Bug fixes

Fix
LAPACKE_*tpmqrt_work
for rowmajor matrices by @weslleyspereira in PR 540. 
Fix leading dimension check in LAPACKE’s
*geesv[x]
and*gges[x]
by @angsch in PR 665. 
Fix the leftlooking variant of GEQRF by @weslleyspereira in PR 690.

Fix workspace query for
*SYEVD
and*HEEVD
routines by neillindquist@neillindquist in PR 691. 
Fix behavior of
SCALE
in*LATBS
and*LATRS
, and avoids NaN generation if entries inCNORM
exceed the overflow threshold by @angsch in PR 712.
3. Developer list

Weslley da Silva Pereira (University of Colorado Denver, USA)

Igor Kozachenko (University of California, Berkeley, USA)

Julie Langou (University of Tennessee, USA)

Jim Demmel (University of California, Berkeley, USA)

Jack Dongarra (University of Tennessee and ORNL, USA)

Julien Langou (University of Colorado Denver, USA)
3.1 New Contributors

@ACSimon33 made their first contribution in PR 686

neillindquist@neillindquist made their first contribution in PR 691

MonicaLiu0311@MonicaLiu0311 made their first contribution in PR 720
4. Thanks again!

MathWorks: Penny Anderson, Mary Ann Freeman, Bobby Cheng, Pat Quillen, Christine Tobler, Heiko Weichelt.

GitHub Users: @angsch, @Christoph Conrads @martinfrbg, @thijssteel
Github contribution details here
Thanks you all!