BLAS/SRC/ssyrk.f(3)

💖 BLAS/SRC/ssyrk.f — the tea ☕

okay bestie, gather round, because today we're talking about ssyrk from LAPACK's BLAS folder. it lives at BLAS/SRC/ssyrk.f and it is, and i say this with my whole chest, the moment.

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ssyrk (uplo, trans, n, k, alpha, a, lda, beta, c, ldc)

SSYRK

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🦋 Function/Subroutine Documentation 🦋

subroutine ssyrk (character uplo, character trans, integer n, integer k,
    real alpha, real, dimension(lda,*) a, integer lda, real beta, real,
    dimension(ldc,*) c, integer ldc)

SSYRK

🎀 Purpose 🎀

so what does she DO. SSYRK performs one of the symmetric rank k operations, and there are two flavors:

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. no cap, that's the whole vibe. 💅

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🌸 Parameters 🌸

okay this is the part where you actually have to pay attention, bestie. every single one. let's go.

• UPLO — UPLO is CHARACTER*1. on entry, UPLO specifies whether the upper or lower triangular part of the array C is to be referenced as follows:
  • 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 — TRANS is CHARACTER*1. on entry, TRANS specifies the operation to be performed as follows:
  • 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 — N is INTEGER. on entry, N specifies the order of the matrix C. N must be at least zero. (zero is fine, negative is not, we don't do that here 🚫)
• K — K is 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 — ALPHA is REAL. on entry, ALPHA specifies the scalar alpha. that's it, that's the whole job. 💫
• A — A is REAL 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 — LDA is 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 — BETA is REAL. on entry, BETA specifies the scalar beta. her too. 💜
• C — C is REAL 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 — LDC is 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 ).

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👑 Author 👑

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

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🌈 Further Details 🌈

Level 3 Blas routine.

the lore, preserved forever: -- 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 ssyrk.f.

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💫 Author 💫

Generated automatically by Doxygen for LAPACK from the source code.

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and that's the whole page, bestie. no crumbs left. 🫶

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

mwah 💋 go call ssyrk, she's been waiting since 1989 and she has never once disappointed. periodt. ✨🦋🎀