BLAS/SRC/dsyrk.f(3)

💖 NAME 💖

BLAS/SRC/dsyrk.f(3) — from the Library Functions Manual. This page is all about the dsyrk BLAS routine, bestie. It’s giving symmetric rank-k update energy, and honestly? Iconic. 💅

✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

• subroutine dsyrk (uplo, trans, n, k, alpha, a, lda, beta, c, ldc) — DSYRK

🦋 Function/Subroutine Documentation 🦋

   subroutine dsyrk (character uplo, character trans, integer n, integer k,
       double precision alpha, double precision, dimension(lda,*) a, integer
       lda, double precision beta, double precision, dimension(ldc,*) c,
       integer ldc)

DSYRK

🌸 Purpose 🌸

Okay so DSYRK performs one of the symmetric rank k operations:

C := alpha*A*A**T + beta*C,

or

C := alpha*A**T*A + beta*C,

where alpha and beta are scalars, C is an n by n symmetric matrix, and A is an n by k matrix in the first case and a k by n matrix in the second case. Linear algebra slay ✨

🌺 Parameters 🌺

• UPLO — CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the array C is to be referenced, like this:
  • 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 — CHARACTER*1. On entry, TRANS specifies the operation to be performed, like this:
  • TRANS = 'N' or 'n' — C := alpha*A*A**T + beta*C.
  • TRANS = 'T' or 't' — C := alpha*A**T*A + beta*C.
  • TRANS = 'C' or 'c' — C := alpha*A**T*A + beta*C.
• N — INTEGER. On entry, N specifies the order of the matrix C. N must be at least zero.
• K — INTEGER. On entry with TRANS = 'N' or 'n', K specifies the number of columns of the matrix A; and on entry with TRANS = 'T' or 't' or 'C' or 'c', K specifies the number of rows of the matrix A. K must be at least zero.
• ALPHA — DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha.
• A — DOUBLE PRECISION 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 — 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 — DOUBLE PRECISION. On entry, BETA specifies the scalar beta.
• C — DOUBLE PRECISION 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 symmetric 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 symmetric 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.
• LDC — 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.

Definition at line 168 of file dsyrk.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie. LAPACK Version 3.12.0 · BLAS/SRC/dsyrk.f(3) · 8-February-1989 — byeee 💅✨