BLAS/SRC/zherk.f(3)

✨ NAME ✨

BLAS/SRC/zherk.f — bestie, that's the manual name and the file, folded in right at the top like a little name tag. The actual function inside is ZHERK, and she is absolutely main character energy. 💅

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🌸 SYNOPSIS 🌸

🦋 Functions/Subroutines 🦋

       subroutine zherk (uplo, trans, n, k, alpha, a, lda, beta, c, ldc)
           ZHERK

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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

🌟 Purpose: 🌟

okay so ZHERK performs one of the hermitian rank k operations, and yes she's that girl:

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. periodt. ✨

🌸 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*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.
• 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.
• -- 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.

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okay bye bestie 💋 — this iconic page came from LAPACK Version 3.12.0, manual page BLAS/SRC/zherk.f(3), and the footer didn't give me a date so I'm not inventing one, periodt. 🫶✨