BLAS/SRC/ssyr.f(3)

🎀 BLAS/SRC/ssyr.f(3) — Library Functions Manual

Okay bestie, this page is from the Library Functions Manual, and it's all about BLAS/SRC/ssyr.f — the Fortran source page for the ssyr routine. Let's get into it. 💅

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🌸 NAME

BLAS/SRC/ssyr.f — that's the name, periodt. It's the page for the ssyr subroutine in the BLAS source. ✨

✨ SYNOPSIS

🫶 Functions/Subroutines

• subroutine ssyr (uplo, n, alpha, x, incx, a, lda) — SSYR

subroutine ssyr (uplo, n, alpha, x, incx, a, lda)
    SSYR

💅 Function/Subroutine Documentation

subroutine ssyr (character uplo, integer n, real alpha, real, dimension(*)
    x, integer incx, real, dimension(lda,*) a, integer lda)

SSYR

🦋 Purpose

Okay so SSYR performs the symmetric rank 1 operation:

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

where alpha is a real scalar, x is an n element vector and A is an n by n symmetric matrix. It's giving "update A with alpha times x times x transpose plus A," and honestly? Iconic. 🌈

🌈 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.
• N — N is INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero.
• ALPHA — ALPHA is REAL. On entry, ALPHA specifies the scalar alpha.
• X — X is REAL 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.
• A — A is REAL array, dimension ( LDA, N ).
  • With UPLO = 'U' or 'u': before entry, 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.
  • With UPLO = 'L' or 'l': before entry, 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 ).

👑 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 131 of file ssyr.f.

🫶 Author

Generated automatically by Doxygen for LAPACK from the source code.

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Okay bestie, that's the whole ssyr page! 💖 Footer vibe check: LAPACK, Version 3.12.0, BLAS/SRC/ssyr.f(3) — and there's no date listed on this footer, so I'm not gonna invent one. Slay. ✨🦋