root / src / blas / cswap.f @ 7
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1 | 1 | equemene | SUBROUTINE CSWAP(N,CX,INCX,CY,INCY) |
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2 | 1 | equemene | * .. Scalar Arguments .. |
3 | 1 | equemene | INTEGER INCX,INCY,N |
4 | 1 | equemene | * .. |
5 | 1 | equemene | * .. Array Arguments .. |
6 | 1 | equemene | COMPLEX CX(*),CY(*) |
7 | 1 | equemene | * .. |
8 | 1 | equemene | * |
9 | 1 | equemene | * Purpose |
10 | 1 | equemene | * ======= |
11 | 1 | equemene | * |
12 | 1 | equemene | * interchanges two vectors. |
13 | 1 | equemene | * jack dongarra, linpack, 3/11/78. |
14 | 1 | equemene | * modified 12/3/93, array(1) declarations changed to array(*) |
15 | 1 | equemene | * |
16 | 1 | equemene | * |
17 | 1 | equemene | * .. Local Scalars .. |
18 | 1 | equemene | COMPLEX CTEMP |
19 | 1 | equemene | INTEGER I,IX,IY |
20 | 1 | equemene | * .. |
21 | 1 | equemene | IF (N.LE.0) RETURN |
22 | 1 | equemene | IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20 |
23 | 1 | equemene | * |
24 | 1 | equemene | * code for unequal increments or equal increments not equal |
25 | 1 | equemene | * to 1 |
26 | 1 | equemene | * |
27 | 1 | equemene | IX = 1 |
28 | 1 | equemene | IY = 1 |
29 | 1 | equemene | IF (INCX.LT.0) IX = (-N+1)*INCX + 1 |
30 | 1 | equemene | IF (INCY.LT.0) IY = (-N+1)*INCY + 1 |
31 | 1 | equemene | DO 10 I = 1,N |
32 | 1 | equemene | CTEMP = CX(IX) |
33 | 1 | equemene | CX(IX) = CY(IY) |
34 | 1 | equemene | CY(IY) = CTEMP |
35 | 1 | equemene | IX = IX + INCX |
36 | 1 | equemene | IY = IY + INCY |
37 | 1 | equemene | 10 CONTINUE |
38 | 1 | equemene | RETURN |
39 | 1 | equemene | * |
40 | 1 | equemene | * code for both increments equal to 1 |
41 | 1 | equemene | 20 DO 30 I = 1,N |
42 | 1 | equemene | CTEMP = CX(I) |
43 | 1 | equemene | CX(I) = CY(I) |
44 | 1 | equemene | CY(I) = CTEMP |
45 | 1 | equemene | 30 CONTINUE |
46 | 1 | equemene | RETURN |
47 | 1 | equemene | END |