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SSYRK(3) | BLAS routine | SSYRK(3) |
NAME¶
SSYRK - perform one of the symmetric rank k operations C := alpha*A*A' + beta*C,SYNOPSIS¶
- SUBROUTINE SSYRK
- ( UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC )
- CHARACTER*1
- UPLO, TRANS
- INTEGER
- N, K, LDA, LDC
- REAL
- ALPHA, BETA
- REAL
- A( LDA, * ), C( LDC, * )
PURPOSE¶
SSYRK performs one of the symmetric rank k operationsC := alpha*A'*A + beta*C,
PARAMETERS¶
- UPLO - CHARACTER*1.
- On entry, UPLO specifies whether the upper or lower
triangular part of the array C is to be referenced as follows:
- TRANS - CHARACTER*1.
- On entry, TRANS specifies the operation to be performed as
follows:
- N - INTEGER.
- On entry, N specifies the order of the matrix C. N must be at least zero. Unchanged on exit.
- 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. Unchanged on exit.
- ALPHA - REAL .
- On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
- A - REAL array of 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. Unchanged on exit.
- 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 ). Unchanged on exit.
- BETA - REAL .
- On entry, BETA specifies the scalar beta. Unchanged on exit.
- C - REAL array of 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 ).
Unchanged on exit.
16 October 1992 | BLAS routine |