NAME¶

ZSCAL - scales a vector by a constant.

SYNOPSIS¶

subroutine zscal(n,za,zx,incx)

c

scales a vector by a constant.

c

jack dongarra, 3/11/78.

c

modified to correct problem with negative increment, 8/21/90.

double

complex za,zx(1)

integer

i,incx,ix,n

if(n.le.0)return

if(incx.eq.1)go

to 20

c

code for increment not equal to 1

ix

= 1

if(incx.lt.0)ix

= (-n+1)*incx + 1

do

10 i = 1,n

zx(ix)

= za*zx(ix)

ix

= ix + incx

10

continue

return

c

code for increment equal to 1

20

do 30 i = 1,n

zx(i)

= za*zx(i)

30

continue

return

end

PURPOSE¶