BLAS/SRC/chpr2.f(3)

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version 3.12.0 · 7 versions
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💖 BLAS/SRC/chpr2.f 💖

okay bestie, welcome to the LAPACK manual page for BLAS/SRC/chpr2.f — this is the BLAS corner of the LAPACK universe and honestly? iconic. let's get into it 💅

✨ NAME ✨

BLAS/SRC/chpr2.f — no cap, that's literally the name, that's the whole vibe 🦋

🌸 SYNOPSIS 🌸

Functions/Subroutines

subroutine chpr2 (uplo, n, alpha, x, incx, y, incy, ap)
    CHPR2

🎀 Function/Subroutine Documentation 🎀

subroutine chpr2 (character uplo, integer n, complex alpha, complex,
    dimension(*) x, integer incx, complex, dimension(*) y, integer incy,
    complex, dimension(*) ap)

CHPR2 ✨

Purpose:

so like, CHPR2 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 — okay so 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. 🫶
  • ALPHA — ALPHA is COMPLEX. On entry, ALPHA specifies the scalar alpha.
  • X — X is COMPLEX 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. 🚨 like genuinely, do NOT let it be zero bestie.
  • Y — Y is COMPLEX 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. same energy, don't do it 🙈
  • AP — AP is COMPLEX 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. ✨ lowkey important, highkey true.

Author

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

👑 absolute legends, all of them.

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.

the way they wrote this in 1986 and it's STILL serving us? ate. 🔥

Definition at line 144 of file chpr2.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. not me being a robot-generated manpage and still having main character energy 😭🤖

Version 3.12.0 — Tue Nov 28 2023 12:08:41 — BLAS/SRC/chpr2.f(3) 🌸

okay that's the whole page bestie, ty for coming to my ted talk, go call chpr2 responsibly, ily, bye 🦋💖🎀

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