BLAS/SRC/ssymm.f(3)

💖 NAME 💖

BLAS/SRC/ssymm.f — okay bestie, this is the Library Functions Manual page for BLAS/SRC/ssymm.f(3), and it's all about the ssymm subroutine. It's giving symmetric matrix-matrix operations, and we're gonna read it properly. 💅

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✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

• subroutine ssymm (side, uplo, m, n, alpha, a, lda, b, ldb, beta, c, ldc) — SSYMM

💅 Function/Subroutine Documentation 💅

Here's the exact signature, character for character — no cap:

subroutine ssymm (character side, character uplo, integer m, integer n, real
    alpha, real, dimension(lda,*) a, integer lda, real, dimension(ldb,*) b,
    integer ldb, real beta, real, dimension(ldc,*) c, integer ldc)

SSYMM

🌸 Purpose 🌸

SSYMM performs one of the matrix-matrix operations

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

or

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

where alpha and beta are scalars, A is a symmetric matrix and B and C are m by n matrices.

🎀 Parameters 🎀

• SIDE — SIDE is CHARACTER*1. On entry, SIDE specifies whether the symmetric matrix A appears on the left or right in the operation as follows:
  • SIDE = 'L' or 'l' → C := alpha*A*B + beta*C,
  • SIDE = 'R' or 'r' → C := alpha*B*A + beta*C,
• UPLO — UPLO is CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the symmetric matrix A is to be referenced as follows:
  • UPLO = 'U' or 'u' → Only the upper triangular part of the symmetric matrix is to be referenced.
  • UPLO = 'L' or 'l' → Only the lower triangular part of the symmetric matrix is to be referenced.
• M — M is INTEGER. On entry, M specifies the number of rows of the matrix C. M must be at least zero.
• N — N is INTEGER. On entry, N specifies the number of columns of the matrix C. N must be at least zero.
• ALPHA — ALPHA is REAL. On entry, ALPHA specifies the scalar alpha.
• A — A is REAL array, dimension ( LDA, ka ), where ka is m when SIDE = 'L' or 'l' and is n otherwise.
  • Before entry with SIDE = 'L' or 'l', the m by m part of the array A must contain the symmetric matrix, such that when UPLO = 'U' or 'u', the leading m by m 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, and when UPLO = 'L' or 'l', the leading m by m 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.
  • Before entry with SIDE = 'R' or 'r', the n by n part of the array A must contain the symmetric matrix, such that when UPLO = 'U' or 'u', 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, and when UPLO = 'L' or 'l', 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.
• LDA — LDA is INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When SIDE = 'L' or 'l' then LDA must be at least max( 1, m ), otherwise LDA must be at least max( 1, n ).
• B — B is REAL array, dimension ( LDB, N ). Before entry, the leading m by n part of the array B must contain the matrix B.
• LDB — LDB is INTEGER. On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. LDB must be at least max( 1, m ).
• BETA — BETA is REAL. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then C need not be set on input.
• C — C is REAL array, dimension ( LDC, N ). Before entry, the leading m by n part of the array C must contain the matrix C, except when beta is zero, in which case C need not be set on entry. On exit, the array C is overwritten by the m by n 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, m ).

👑 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 188 of file ssymm.f.

🧚 Author 🧚

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Okay that's the whole page, bestie — sign-off from LAPACK Version 3.12.0, page BLAS/SRC/ssymm.f(3). The footer is date-free, so we're not inventing one; periodt. 🫶✨