BLAS/SRC/zherk.f(3)

BLAS/SRC/zherk.f(3) 💖

okay bestie, you're in the LAPACK section of the manual, and this little cutie lives at BLAS/SRC/zherk.f ✨

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🌸 NAME 🌸

BLAS/SRC/zherk.f — no cap, that's the whole vibe of the name section 💅

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✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine zherk (uplo, trans, n, k, alpha, a, lda, beta, c, ldc) — ZHERK, our main character 👑

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🎀 Function/Subroutine Documentation 🎀

subroutine zherk (character uplo, character trans, integer n, integer k, double precision alpha, complex*16, dimension(lda,*) a, integer lda, double precision beta, complex*16, dimension(ldc,*) c, integer ldc)

ZHERK — she's HERE and she's doing linear algebra 💖

💜 Purpose

okay so, ZHERK performs one of the hermitian rank k operations

   C := alpha*A*A**H + beta*C,

or

   C := alpha*A**H*A + beta*C,

where alpha and beta are real scalars, C is an n by n hermitian matrix, and A is an n by k matrix in the first case and a k by n matrix in the second case. two flavors, one icon 🦋

🧚 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, like so:
  • 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, bestie:
  • TRANS = 'N' or 'n' — C := alpha*A*A**H + beta*C.
  • TRANS = 'C' or 'c' — C := alpha*A**H*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, she's flexible 💅)
• K — K is INTEGER. On entry with TRANS = 'N' or 'n', K specifies the number of columns of the matrix A, and on entry with TRANS = 'C' or 'c', K specifies the number of rows of the matrix A. K must be at least zero.
• ALPHA — ALPHA is DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha. 🍓
• A — A is COMPLEX*16 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 ).
• BETA — BETA is DOUBLE PRECISION. On entry, BETA specifies the scalar beta.
• C — C is COMPLEX*16 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 hermitian 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 hermitian 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. ✨
  • > Note that the imaginary parts of the diagonal elements need not be set, they are assumed to be zero, and on exit they are set to zero. 🫶
• 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.

🌈 Further Details

Level 3 Blas routine. the whole squad showed up 🔥

-- 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.

-- Modified 8-Nov-93 to set C(J,J) to DBLE( C(J,J) ) when BETA = 1.
   Ed Anderson, Cray Research Inc.

⭐ Definition at line 172 of file zherk.f.

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🦋 Author

Generated automatically by Doxygen for LAPACK from the source code. (yes queen, the docs wrote themselves, iconic behavior 💅✨)

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and that's the whole page, bestie!! version 3.12.0, dated Tue Nov 28 2023 12:08:41, and yeah that footer is just the LAPACK/BLAS glow-up of BLAS/SRC/zherk.f(3) — slay, periodt 💖🎀🦋