# naginterfaces.library.blast.daxpby¶

naginterfaces.library.blast.daxpby(alpha, x, beta, y)[source]

daxpby computes the sum of two scaled vectors, for real vectors and scalars.

For full information please refer to the NAG Library document for f16ec

https://www.nag.com/numeric/nl/nagdoc_27.3/flhtml/f16/f16ecf.html

Parameters
alphafloat

The scalar .

xfloat, array-like, shape

The -element vector .

If , must be stored in , for .

If , is not referenced.

betafloat

The scalar .

yfloat, ndarray, shape , modified in place

On entry: the -element vector .

If , must be stored in , for .

If , must be stored in , for .

Intermediate elements of are not referenced.

On exit: the updated vector stored in the array elements used to supply the original vector .

Intermediate elements of are unchanged.

Raises
NagValueError
(errno )

On entry, error in parameter .

Constraint: .

(errno )

On entry, error in parameter .

Constraint: .

Notes

daxpby performs the operation

where and are -element real vectors, and and real scalars. If is equal to zero, or if is equal to zero and is equal to , this function returns immediately.

References

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