HP MLIB User's Guide Vol. 1 7th Ed.

Chapter 3 Basic Matrix Operations 215

Matrix-vector multiply SGBMV/DGBMV/CGBMV/ZGBMV

kl The lower bandwidth of A, that is, the number of

nonzero diagonals below the principal diagonal in the

band, 0 ≤ kl < n.

ku The upper bandwidth of A, that is, the number of

nonzero diagonals above the principal diagonal in the

band, 0 ≤ ku < n.

alpha The scalar α. If alpha = 0, the subprograms compute

y ←βy without referencing ab or x.

ab Array containing the m-by-n band matrix A in the

compressed form described above. If a

is in the band,

it is stored in ab(ku+1+i−j,j). The columns of A are

stored in the columns of ab, and the diagonals of A are

stored in rows 1 through kl+ku+1.

ldab The leading dimension of array ab as declared in the

calling program unit, with ldab ≥ kl+ku+1.