Sparse elementary vector operation

SAXPYI/DAXPYI/CAXPYI/ZAXPYI

 

INTEGER*8

m, indx(m)

 

COMPLEX*8

a, x(m), y(n)

 

CALL CAXPYI(m, a, x, indx, y)

 

INTEGER*8

m, indx(m)

 

COMPLEX*16

a, x(m), y(n)

 

CALL ZAXPYI(m, a, x, indx, y)

Input

m

Number of interesting elements of x, m n, where n is

 

 

the length of y. If m ≤ 0, the subprograms do not

 

 

reference x, indx, or y.

 

a

The scalar a.

 

x

Array of length m containing the interesting elements

 

 

of x. x(j) = xi if indx(j) = i.

Chapter 2 Basic Vector Operations 69