root / src / blas / zdotc.f @ 8
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1 | 1 | equemene | DOUBLE COMPLEX FUNCTION ZDOTC(N,ZX,INCX,ZY,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 | DOUBLE COMPLEX ZX(*),ZY(*) |
7 | 1 | equemene | * .. |
8 | 1 | equemene | * |
9 | 1 | equemene | * Purpose |
10 | 1 | equemene | * ======= |
11 | 1 | equemene | * |
12 | 1 | equemene | * ZDOTC forms the dot product of a vector. |
13 | 1 | equemene | * |
14 | 1 | equemene | * Further Details |
15 | 1 | equemene | * =============== |
16 | 1 | equemene | * |
17 | 1 | equemene | * jack dongarra, 3/11/78. |
18 | 1 | equemene | * modified 12/3/93, array(1) declarations changed to array(*) |
19 | 1 | equemene | * |
20 | 1 | equemene | * .. Local Scalars .. |
21 | 1 | equemene | DOUBLE COMPLEX ZTEMP |
22 | 1 | equemene | INTEGER I,IX,IY |
23 | 1 | equemene | * .. |
24 | 1 | equemene | * .. Intrinsic Functions .. |
25 | 1 | equemene | INTRINSIC DCONJG |
26 | 1 | equemene | * .. |
27 | 1 | equemene | ZTEMP = (0.0d0,0.0d0) |
28 | 1 | equemene | ZDOTC = (0.0d0,0.0d0) |
29 | 1 | equemene | IF (N.LE.0) RETURN |
30 | 1 | equemene | IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20 |
31 | 1 | equemene | * |
32 | 1 | equemene | * code for unequal increments or equal increments |
33 | 1 | equemene | * not equal to 1 |
34 | 1 | equemene | * |
35 | 1 | equemene | IX = 1 |
36 | 1 | equemene | IY = 1 |
37 | 1 | equemene | IF (INCX.LT.0) IX = (-N+1)*INCX + 1 |
38 | 1 | equemene | IF (INCY.LT.0) IY = (-N+1)*INCY + 1 |
39 | 1 | equemene | DO 10 I = 1,N |
40 | 1 | equemene | ZTEMP = ZTEMP + DCONJG(ZX(IX))*ZY(IY) |
41 | 1 | equemene | IX = IX + INCX |
42 | 1 | equemene | IY = IY + INCY |
43 | 1 | equemene | 10 CONTINUE |
44 | 1 | equemene | ZDOTC = ZTEMP |
45 | 1 | equemene | RETURN |
46 | 1 | equemene | * |
47 | 1 | equemene | * code for both increments equal to 1 |
48 | 1 | equemene | * |
49 | 1 | equemene | 20 DO 30 I = 1,N |
50 | 1 | equemene | ZTEMP = ZTEMP + DCONJG(ZX(I))*ZY(I) |
51 | 1 | equemene | 30 CONTINUE |
52 | 1 | equemene | ZDOTC = ZTEMP |
53 | 1 | equemene | RETURN |
54 | 1 | equemene | END |