[linalg.algs.blas2.rank1,linalg.algs.blas2.symherrank1] Restore missing arguments in P3371R5 updating overloads#8995
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tkoeppe merged 2 commits intoMay 12, 2026
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…ects The non-ExecutionPolicy codeblock dispatches to the overwriting 3-argument matrix_rank_1_update, dropping the InMat E parameter and computing A = x conj(y)^T instead of the specified A = E + x conj(y)^T. The ExecutionPolicy branch already passes E.
The detailed declaration drops in-vector InVec, in-matrix InMat, Scalar alpha, and InMat E, even though the Effects compute A = E + alpha x x^H and the Remarks state "A may alias E". Match the synopsis.
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May 12, 2026
| equivalent to: | ||
| \begin{codeblock} | ||
| matrix_rank_1_update(x, conjugated(y), A); | ||
| matrix_rank_1_update(x, conjugated(y), E, A); |
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This was a misapplication of the paper, it was correct in https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2025/p3371r5.html#specification-of-nonsymmetric-rank-1-update-functions
| @\exposconcept{scalar}@ Scalar, @\exposconcept{in-vector}@ InVec, @\exposconcept{in-matrix}@ InMat, @\exposconcept{possibly-packed-out-matrix}@ OutMat, | ||
| class Triangle> | ||
| void hermitian_matrix_rank_1_update(ExecutionPolicy&& exec, | ||
| Scalar alpha, InVec x, InMat E, OutMat A, Triangle t); |
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Also a misapplication of the paper, it was correct at https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2025/p3371r5.html#specification-of-symmetric-and-hermitian-rank-1-update-functions
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Thank you both! |
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The detailed wording for two updating overloads introduced by P3371R5 is inconsistent with the synopsis and surrounding effects wording.
[linalg.algs.blas2.rank1]—matrix_rank_1_update_cnon-ExecutionPolicyEffects codeblock dispatches to the 3-arg overwriting overload, droppingE.[linalg.algs.blas2.symherrank1]— updatinghermitian_matrix_rank_1_updatedetailed declaration dropsin-vector InVec,in-matrix InMat,Scalar alpha, andInMat E, even though Effects computeA = E + alpha x x^Hand Remarks state "A may alias E".