Visible to Intel only — GUID: GUID-7D89EB9A-7DED-4E36-B6B0-9C3B31DDBF6D
Visible to Intel only — GUID: GUID-7D89EB9A-7DED-4E36-B6B0-9C3B31DDBF6D
?sfrk
Performs a symmetric rank-k operation for matrix in RFP format.
Syntax
call ssfrk(transr, uplo, trans, n, k, alpha, a, lda, beta, c)
call dsfrk(transr, uplo, trans, n, k, alpha, a, lda, beta, c)
Include Files
- mkl.fi
Description
The ?sfrk routines perform a matrix-matrix operation using symmetric matrices. The operation is defined as
C := alpha*A*AT + beta*C,
or
C := alpha*AT*A + beta*C,
where:
alpha and beta are scalars,
C is an n-by-n symmetric matrix in rectangular full packed (RFP) format,
A is an n-by-k matrix in the first case and a k-by-n matrix in the second case.
Input Parameters
- transr
-
CHARACTER*1.
if transr = 'N' or 'n', the normal form of RFP C is stored;
if transr= 'T' or 't', the transpose form of RFP C is stored.
- uplo
-
CHARACTER*1. Specifies whether the upper or lower triangular part of the array c is used.
If uplo = 'U' or 'u', then the upper triangular part of the array c is used.
If uplo = 'L' or 'l', then the low triangular part of the array c is used.
- trans
-
CHARACTER*1. Specifies the operation:
if trans = 'N' or 'n', then C := alpha*A*AT + beta*C;
if trans = 'T' or 't', then C := alpha*AT*A + beta*C;
- n
-
INTEGER. Specifies the order of the matrix C. The value of 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', k specifies the number of rows of the matrix A.
The value of k must be at least zero.
- alpha
-
REAL for ssfrk
DOUBLE PRECISION for dsfrk
Specifies the scalar alpha.
- a
-
REAL for ssfrk
DOUBLE PRECISION for dsfrk
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. Specifies the leading 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
-
REAL for ssfrk
DOUBLE PRECISION for dsfrk
Specifies the scalar beta.
- c
-
REAL for ssfrk
DOUBLE PRECISION for dsfrk
Array, size (n*(n+1)/2 ). Before entry contains the symmetric matrix C in RFP format.
Output Parameters
- c
-
If trans = 'N' or 'n', then c contains C := alpha*A*A' + beta*C;
if trans = 'T' or 't', then c contains C := alpha*A'*A + beta*C;