BLAS/SRC/zhpr2.f(3)

💖 BLAS/SRC/zhpr2.f(3) — Library Functions Manual 💖

✨ NAME ✨

BLAS/SRC/zhpr2.f — okay so this is the manual page for the ZHPR2 BLAS routine, and it’s lowkey a whole vibe. 💅

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🌸 SYNOPSIS 🌸

Functions/Subroutines

subroutine zhpr2 (uplo, n, alpha, x, incx, y, incy, ap)
    ZHPR2

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🫶 Function/Subroutine Documentation 🫶

subroutine zhpr2 (character uplo, integer n, complex*16 alpha, complex*16,
    dimension(*) x, integer incx, complex*16, dimension(*) y, integer incy,
    complex*16, dimension(*) ap)
    ZHPR2

💅 Purpose

Bestie, ZHPR2 performs the hermitian rank 2 operation:

A := alpha*x*y**H + conjg( alpha )*y*x**H + A,

where alpha is a scalar, x and y are n element vectors and A is an n by n hermitian matrix, supplied in packed form. Periodt. ✨

🎀 Parameters

UPLO

UPLO is CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the matrix A is supplied in the packed array AP as follows:

• UPLO = 'U' or 'u' — the upper triangular part of A is supplied in AP.
• UPLO = 'L' or 'l' — the lower triangular part of A is supplied in AP.

N

N is INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero. No cap.

ALPHA

ALPHA is COMPLEX*16. On entry, ALPHA specifies the scalar alpha.

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.

INCX

INCX is INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.

Y

Y is COMPLEX*16 array, dimension at least ( 1 + ( n - 1 )*abs( INCY ) ). Before entry, the incremented array Y must contain the n element vector y.

INCY

INCY is INTEGER. On entry, INCY specifies the increment for the elements of Y. INCY must not be zero.

AP

AP is COMPLEX*16 array, dimension at least ( ( n*( n + 1 ) )/2 ).

Before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular part of the hermitian matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. On exit, the array AP is overwritten by the upper triangular part of the updated matrix.

Before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular part of the hermitian matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. On exit, the array AP 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. Iykyk. 🫶

👑

Author

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

🌈 Further Details

• Level 2 Blas routine.
• -- Written on 22-October-1986.
  • Jack Dongarra, Argonne National Lab.
  • Jeremy Du Croz, Nag Central Office.
  • Sven Hammarling, Nag Central Office.
  • Richard Hanson, Sandia National Labs.

Definition at line 144 of file zhpr2.f.

🦋 Author

Generated automatically by Doxygen for LAPACK from the source code.

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And that’s the whole page, bestie — source/version tea: LAPACK Version 3.12.0, page BLAS/SRC/zhpr2.f(3). The footer didn’t give us a date, so no invented date here, fr fr. 💖✨🎀