The function may be called by the names: f16pec, nag_blast_dspmv or nag_dspmv.
3Description
f16pec performs the matrix-vector operation
where is an by real symmetric matrix stored in packed form, and are -element real vectors, and and are real scalars.
4References
Basic Linear Algebra Subprograms Technical (BLAST) Forum (2001) Basic Linear Algebra Subprograms Technical (BLAST) Forum Standard University of Tennessee, Knoxville, Tennessee https://www.netlib.org/blas/blast-forum/blas-report.pdf
5Arguments
1: – Nag_OrderTypeInput
On entry: the order argument specifies the two-dimensional storage scheme being used, i.e., row-major ordering or column-major ordering. C language defined storage is specified by . See Section 3.1.3 in the Introduction to the NAG Library CL Interface for a more detailed explanation of the use of this argument.
Constraint:
or .
2: – Nag_UploTypeInput
On entry: specifies whether the upper or lower triangular part of is stored.
The upper triangular part of is stored.
The lower triangular part of is stored.
Constraint:
or .
3: – IntegerInput
On entry: , the order of the matrix .
Constraint:
.
4: – doubleInput
On entry: the scalar .
5: – const doubleInput
Note: the dimension, dim, of the array ap
must be at least
.
On entry: the by symmetric matrix , packed by rows or columns.
The storage of elements depends on the order and uplo arguments as follows:
if and ,
is stored in , for ;
if and ,
is stored in , for ;
if and ,
is stored in , for ;
if and ,
is stored in , for .
6: – const doubleInput
Note: the dimension, dim, of the array x
must be at least
.
On entry: the -element vector .
If ,
must be stored in , for .
If ,
must be stored in , for .
Intermediate elements of x are not referenced. If , x is not referenced and may be NULL.
7: – IntegerInput
On entry: the increment in the subscripts of x between successive elements of .
Constraint:
.
8: – doubleInput
On entry: the scalar .
9: – doubleInput/Output
Note: the dimension, dim, of the array y
must be at least
.
On entry: the vector . See x for details of storage.
On entry: the increment in the subscripts of y between successive elements of .
Constraint:
.
11: – NagError *Input/Output
The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).
6Error Indicators and Warnings
NE_ALLOC_FAIL
Dynamic memory allocation failed.
See Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
NE_BAD_PARAM
On entry, argument had an illegal value.
NE_INT
On entry, .
Constraint: .
On entry, .
Constraint: .
On entry, .
Constraint: .
NE_NO_LICENCE
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library CL Interface for further information.