scipy.linalg.blas.dsbmv

scipy.linalg.blas.dsbmv(k, alpha, a, x, incx=1, offx=0, beta=0.0, y=None, incy=1, offy=0, lower=0, overwrite_y=0) = <fblas function dsbmv>

Compute y = alpha*a@x + beta*y for a banded symmetric matrix a (BLAS dsbmv).

Parameters:

kint

Number of super-diagonals (or sub-diagonals) of the band.

alphafloat

Scalar multiplier for the product.

andarray

Banded storage of the symmetric matrix, shape (k + 1, n).

xndarray

Input vector.

incxint, optional

Stride between successive elements of x. Default is 1.

offxint, optional

Index of the first element of x to use. Default is 0.

betafloat, optional

Scalar multiplier for y. Default is 0.

yndarray, optional

Input/output vector; if omitted a new zero vector is allocated. Default is None.

incyint, optional

Stride between successive elements of y. Default is 1.

offyint, optional

Index of the first element of y to use. Default is 0.

lowerint, optional

If 0, the upper triangle is used; if 1, the lower. Default is 0.

overwrite_yint, optional

If nonzero, y may be overwritten in place. Default is 0.

Returns:

yndarray

The vector alpha*a@x + beta*y.