SRC/zsyr.f(3)

SRC/zsyr.f from the Library Functions Manual — okay bestie, this one’s a whole little routine and it’s lowkey iconic. 🫶

🌸 NAME 🌸

SRC/zsyr.f

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

• subroutine zsyr (uplo, n, alpha, x, incx, a, lda) — ZSYR performs the symmetric rank-1 update of a complex symmetric matrix.

💖 Function/Subroutine Documentation 💖

subroutine zsyr (character uplo, integer n, complex*16 alpha, complex*16, dimension( * ) x, integer incx, complex*16, dimension( lda, * ) a, integer lda)

ZSYR performs the symmetric rank-1 update of a complex symmetric matrix.

🌟 Purpose 🌟

Okay so ZSYR performs the symmetric rank 1 operation:

A := alpha*x*x**H + A,

where alpha is a complex scalar, x is an n element vector and A is an n by n symmetric matrix.

🎀 Parameters 🎀

• UPLO — UPLO is CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the array A is to be referenced as follows:
  • UPLO = 'U' or 'u' — Only the upper triangular part of A is to be referenced.
  • UPLO = 'L' or 'l' — Only the lower triangular part of A is to be referenced.

Unchanged on exit.

• N — N is INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit.
• ALPHA — ALPHA is COMPLEX*16. On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
• X — X is COMPLEX*16 array, dimension at least ( 1 + ( N - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the N-element vector x. Unchanged on exit.
• INCX — INCX is INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit.
• A — A is COMPLEX*16 array, dimension ( LDA, N ). Before entry, with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must contain the upper triangular part of the symmetric matrix and the strictly lower triangular part of A is not referenced. On exit, the upper triangular part of the array A 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 A must contain the lower triangular part of the symmetric matrix and the strictly upper triangular part of A is not referenced. On exit, the lower triangular part of the array A is overwritten by the lower triangular part of the updated matrix.
• LDA — LDA is INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, N ). Unchanged on exit.

🫶 Author 🫶

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

Definition at line 134 of file zsyr.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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That's the whole vibe check, bestie! Signing off from SRC/zsyr.f(3), LAPACK Version 3.12.0 — muah 💋