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