Note: before using this routine, please read the Users' Note for your implementation to check the interpretation of bold italicised terms and other implementation-dependent details.
F06SKF (ZTBSV) performs one of the matrix-vector operations
where is an by complex triangular band matrix with subdiagonals or superdiagonals, and is an -element complex vector. denotes or equivalently ; denotes or equivalently .
No test for singularity or near-singularity of is included in this routine. Such tests must be performed before calling this routine.
4 References
None.
5 Parameters
1: UPLO – CHARACTER(1)Input
On entry: specifies whether is upper or lower triangular.
is upper triangular.
is lower triangular.
Constraint:
or .
2: TRANS – CHARACTER(1)Input
On entry: specifies the operation to be performed.
.
.
.
Constraint:
, or .
3: DIAG – CHARACTER(1)Input
On entry: 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.
Constraint:
or .
4: N – INTEGERInput
On entry: , the order of the matrix .
Constraint:
.
5: K – INTEGERInput
On entry: , the number of subdiagonals or superdiagonals of the matrix .