/home/abui...C/csyr2k.f(3)

🦋 /home/abui...C/csyr2k.f(3) — ok bestie, this one's from the Library Functions Manual and it's lowkey iconic 💅

So this page is literally documenting /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/csyr2k.f and no cap, it's a whole vibe — a Level 3 BLAS routine that lives rent-free in LAPACK. Let's get into it 🎀

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine CSYR2K (uplo, trans, n, k, alpha, a, lda, b, ldb, beta, c,
    ldc)

• CSYR2K — that's her, that's the girl 🌸

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💖 Function/Subroutine Documentation 💖

subroutine CSYR2K (character uplo, character trans, integer n, integer k,
    complex alpha, complex, dimension(lda,*) a, integer lda, complex,
    dimension(ldb,*) b, integer ldb, complex beta, complex, dimension(ldc,*)
    c, integer ldc)

CSYR2K — okay so here's what she does, bestie 👑

🫶 Purpose

!>
!> CSYR2K  performs one of the symmetric rank 2k operations
!>
!>    C := alpha*A*B**T + alpha*B*A**T + beta*C,
!>
!> or
!>
!>    C := alpha*A**T*B + alpha*B**T*A + beta*C,
!>
!> where  alpha and beta  are scalars,  C is an  n by n symmetric matrix
!> and  A and B  are  n by k  matrices  in the  first  case  and  k by n
!> matrices in the second case.
!>

Like, she's doing a symmetric rank 2k operation — two of them actually, pick your fighter. The math is right there, don't shoot the messenger 😭

🌈 Parameters

• UPLO — UPLO is CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the array C is to be referenced, as follows:
  • UPLO = 'U' or 'u' — Only the upper triangular part of C is to be referenced.
  • UPLO = 'L' or 'l' — Only the lower triangular part of C is to be referenced.
• TRANS — TRANS is CHARACTER*1. On entry, TRANS specifies the operation to be performed, as follows:
  • TRANS = 'N' or 'n' — C := alpha*A*B**T + alpha*B*A**T + beta*C.
  • TRANS = 'T' or 't' — C := alpha*A**T*B + alpha*B**T*A + beta*C.
• N — N is INTEGER. On entry, N specifies the order of the matrix C. N must be at least zero. (Zero is allowed bestie, she's flexible 💅)
• K — K is INTEGER. On entry with TRANS = 'N' or 'n', K specifies the number of columns of the matrices A and B, and on entry with TRANS = 'T' or 't', K specifies the number of rows of the matrices A and B. K must be at least zero.
• ALPHA — ALPHA is COMPLEX. On entry, ALPHA specifies the scalar alpha. That's it, that's the whole description 🎀
• A — A is COMPLEX array, dimension ( LDA, ka ), where ka is k when TRANS = 'N' or 'n', and is n otherwise. Before entry with TRANS = 'N' or 'n', the leading n by k part of the array A must contain the matrix A; otherwise the leading k by n part of the array A must contain the matrix A.
• LDA — LDA is INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When TRANS = 'N' or 'n' then LDA must be at least max( 1, n ), otherwise LDA must be at least max( 1, k ).
• B — B is COMPLEX array, dimension ( LDB, kb ), where kb is k when TRANS = 'N' or 'n', and is n otherwise. Before entry with TRANS = 'N' or 'n', the leading n by k part of the array B must contain the matrix B; otherwise the leading k by n part of the array B must contain the matrix B.
• LDB — LDB is INTEGER. On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. When TRANS = 'N' or 'n' then LDB must be at least max( 1, n ), otherwise LDB must be at least max( 1, k ).
• BETA — BETA is COMPLEX. On entry, BETA specifies the scalar beta. Same energy as ALPHA, honestly 🫶
• C — C is COMPLEX array, dimension ( LDC, N ).
  • Before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array C must contain the upper triangular part of the symmetric matrix, and the strictly lower triangular part of C is not referenced. On exit, the upper triangular part of the array C is overwritten by the upper triangular part of the updated matrix.
  • Before entry with UPLO = 'L' or 'l', the leading n by n lower triangular part of the array C must contain the lower triangular part of the symmetric matrix, and the strictly upper triangular part of C is not referenced. On exit, the lower triangular part of the array C is overwritten by the lower triangular part of the updated matrix.

Ngl bestie, pay attention to which half you're filling. The other half gets straight-up ignored — not read, not touched, not her problem 💀

• LDC — LDC is INTEGER. On entry, LDC specifies the first dimension of C as declared in the calling (sub) program. LDC must be at least max( 1, n ).

👑 Author

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Give it up for the institutions, periodt 🌟

⭐ Further Details:

!>
!>  Level 3 Blas routine.
!>
!>  -- Written on 8-February-1989.
!>     Jack Dongarra, Argonne National Laboratory.
!>     Iain Duff, AERE Harwell.
!>     Jeremy Du Croz, Numerical Algorithms Group Ltd.
!>     Sven Hammarling, Numerical Algorithms Group Ltd.
!>

She's a Level 3 BLAS routine, written on 8-February-1989 by:

• Jack Dongarra, Argonne National Laboratory.
• Iain Duff, AERE Harwell.
• Jeremy Du Croz, Numerical Algorithms Group Ltd.
• Sven Hammarling, Numerical Algorithms Group Ltd.

1989?? Vintage. Antique. Main character energy fr fr 🔥

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Definition at line 187 of file csyr2k.f. Go look, she's literally right there 🦋

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🌸 Author 🌸

Generated automatically by Doxygen for LAPACK from the source code. Not a human, just vibes and a doc generator ✨

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💜 mwah, that's the page! Sending you off with the cutest little sign-off ever: this icon is from LAPACK, Version 3.12.0, and she said see you later bestie 🎀💅🫶