naginterfaces.library.blas.dsfrk¶
- naginterfaces.library.blas.dsfrk(transr, uplo, trans, k, alpha, a, beta, c)[source]¶
dsfrk
performs one of the symmetric rank- update operationswhere is a real matrix, is an real symmetric matrix stored in Rectangular Full Packed (RFP) format, and and are real scalars.
For full information please refer to the NAG Library document for f06wc
https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/f06/f06wcf.html
- Parameters
- transrstr, length 1
Specifies whether the RFP representation of is normal or transposed.
The matrix is stored in normal RFP format.
The matrix is stored in transposed RFP format.
- uplostr, length 1
Specifies whether the upper or lower triangular part of is stored in RFP format.
The upper triangular part of is stored in RFP format.
The lower triangular part of is stored in RFP format.
- transstr, length 1
Specifies the operation to be performed.
.
.
- kint
, the number of columns of if , or the number of rows of if .
- alphafloat
The scalar .
- afloat, array-like, shape
Note: the required extent for this argument in dimension 1 is determined as follows: if : ; if : ; otherwise: .
Note: the required extent for this argument in dimension 2 is determined as follows: if : ; if : ; otherwise: .
The matrix ; is if , or if . If , is not referenced.
- betafloat
The scalar .
- cfloat, array-like, shape
The upper or lower triangular part (as specified by ) of the symmetric matrix , stored in RFP format (as specified by ). The storage format is described in detail in the F07 Introduction.
- Returns
- cfloat, ndarray, shape
The updated matrix , that is its upper or lower triangular part stored in RFP format.
- Raises
- NagValueError
- (errno )
On entry, error in parameter .
Constraint: or .
- (errno )
On entry, error in parameter .
Constraint: or .
- (errno )
On entry, error in parameter .
Constraint: or .
- (errno )
On entry, error in parameter .
Constraint: .
- (errno )
On entry, error in parameter .
Constraint: .
- Notes
No equivalent traditional C interface for this routine exists in the NAG Library.
dsfrk
performs one of the symmetric rank- update operationswhere is a real matrix, is an real symmetric matrix stored in Rectangular Full Packed (RFP) format, and and are real scalars. The RFP storage format is described in the F07 Introduction.
If or if and either or then
dsfrk
returns immediately. If and either or then is set to the zero matrix.
- References
Gustavson, F G, Waśniewski, J, Dongarra, J J and Langou, J, 2010, Rectangular full packed format for Cholesky’s algorithm: factorization, solution, and inversion, ACM Trans. Math. Software (37, 2)