naginterfaces.library.blas.dtrmv¶
- naginterfaces.library.blas.dtrmv(uplo, trans, diag, a, x)[source]¶
dtrmv
computes the matrix-vector product for a real triangular matrix or its transpose.For full information please refer to the NAG Library document for f06pf
https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/f06/f06pff.html
- Parameters
- uplostr, length 1
Specifies whether is upper or lower triangular.
is upper triangular.
is lower triangular.
- transstr, length 1
Specifies the operation to be performed.
.
or
.
- diagstr, length 1
Specifies whether has nonunit or unit diagonal elements.
The diagonal elements are stored explicitly.
The diagonal elements are assumed to be , and are not referenced.
- afloat, array-like, shape
The triangular matrix .
- xfloat, array-like, shape
The -element vector .
- Returns
- xfloat, ndarray, shape
The updated vector .
- 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
In the NAG Library the traditional C interface for this routine uses a different algorithmic base. Please contact NAG if you have any questions about compatibility.
dtrmv
performs one of the matrix-vector operationswhere is an real triangular matrix, and is an -element real vector.