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SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
* .. Scalar Arguments ..
DOUBLE COMPLEX ZA
INTEGER INCX,INCY,N
* ..
* .. Array Arguments ..
DOUBLE COMPLEX ZX(*),ZY(*)
* ..
*
* Purpose
* =======
*
* ZAXPY constant times a vector plus a vector.
*
* Further Details
* ===============
*
* jack dongarra, 3/11/78.
* modified 12/3/93, array(1) declarations changed to array(*)
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I,IX,IY
* ..
* .. External Functions ..
DOUBLE PRECISION DCABS1
EXTERNAL DCABS1
* ..
IF (N.LE.0) RETURN
IF (DCABS1(ZA).EQ.0.0d0) RETURN
IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
*
* code for both increments equal to 1
*
DO I = 1,N
ZY(I) = ZY(I) + ZA*ZX(I)
END DO
ELSE
*
* code for unequal increments or equal increments
* not equal to 1
*
IX = 1
IY = 1
IF (INCX.LT.0) IX = (-N+1)*INCX + 1
IF (INCY.LT.0) IY = (-N+1)*INCY + 1
DO I = 1,N
ZY(IY) = ZY(IY) + ZA*ZX(IX)
IX = IX + INCX
IY = IY + INCY
END DO
END IF
*
RETURN
END
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