SGBMV/DGBMV/CGBMV/ZGBMV

 

Matrix-vector multiply

1

T

x , where ρ is a real

Example 2 Form the REAL*8 matrix-vector product y = --y – ρ A

 

2

 

 

scalar, A is a 6-by-9 real band matrix whose lower bandwidth is 1 and whose upper bandwidth is 2. A is stored in an array AB whose dimensions are 10 by 10, x is a real vector 6 elements long stored in an array X of dimension 10, and y is a real vector 9 elements long stored in an array Y, also of dimension 10.

INTEGER*4

M,N,KL,KU,LDAB

REAL*8

RHO,AB(10,10),X(10),Y(10)

M = 9

 

 

N = 6

 

 

KL =

1

 

KU =

2

 

LDAB

= 10

 

CALL

DGBMV (’TRANSPOSE’,M,N,KL,KU,-RHO,AB,LDAB,X,1,0.5D0,Y,1)

218HP MLIB User’s Guide