1: SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
2: * .. Scalar Arguments ..
3: DOUBLE COMPLEX ZA
4: INTEGER INCX,INCY,N
5: * ..
6: * .. Array Arguments ..
7: DOUBLE COMPLEX ZX(*),ZY(*)
8: * ..
9: *
10: * Purpose
11: * =======
12: *
13: * ZAXPY constant times a vector plus a vector.
14: *
15: * Further Details
16: * ===============
17: *
18: * jack dongarra, 3/11/78.
19: * modified 12/3/93, array(1) declarations changed to array(*)
20: *
21: * =====================================================================
22: *
23: * .. Local Scalars ..
24: INTEGER I,IX,IY
25: * ..
26: * .. External Functions ..
27: DOUBLE PRECISION DCABS1
28: EXTERNAL DCABS1
29: * ..
30: IF (N.LE.0) RETURN
31: IF (DCABS1(ZA).EQ.0.0d0) RETURN
32: IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20
33: *
34: * code for unequal increments or equal increments
35: * not equal to 1
36: *
37: IX = 1
38: IY = 1
39: IF (INCX.LT.0) IX = (-N+1)*INCX + 1
40: IF (INCY.LT.0) IY = (-N+1)*INCY + 1
41: DO 10 I = 1,N
42: ZY(IY) = ZY(IY) + ZA*ZX(IX)
43: IX = IX + INCX
44: IY = IY + INCY
45: 10 CONTINUE
46: RETURN
47: *
48: * code for both increments equal to 1
49: *
50: 20 DO 30 I = 1,N
51: ZY(I) = ZY(I) + ZA*ZX(I)
52: 30 CONTINUE
53: RETURN
54: END
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