root / src / blas / cdotc.f @ 10
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1 | 1 | pfleura2 | COMPLEX FUNCTION CDOTC(N,CX,INCX,CY,INCY) |
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2 | 1 | pfleura2 | * .. Scalar Arguments .. |
3 | 1 | pfleura2 | INTEGER INCX,INCY,N |
4 | 1 | pfleura2 | * .. |
5 | 1 | pfleura2 | * .. Array Arguments .. |
6 | 1 | pfleura2 | COMPLEX CX(*),CY(*) |
7 | 1 | pfleura2 | * .. |
8 | 1 | pfleura2 | * |
9 | 1 | pfleura2 | * Purpose |
10 | 1 | pfleura2 | * ======= |
11 | 1 | pfleura2 | * |
12 | 1 | pfleura2 | * forms the dot product of two vectors, conjugating the first |
13 | 1 | pfleura2 | * vector. |
14 | 1 | pfleura2 | * |
15 | 1 | pfleura2 | * Further Details |
16 | 1 | pfleura2 | * =============== |
17 | 1 | pfleura2 | * |
18 | 1 | pfleura2 | * jack dongarra, linpack, 3/11/78. |
19 | 1 | pfleura2 | * modified 12/3/93, array(1) declarations changed to array(*) |
20 | 1 | pfleura2 | * |
21 | 1 | pfleura2 | * .. Local Scalars .. |
22 | 1 | pfleura2 | COMPLEX CTEMP |
23 | 1 | pfleura2 | INTEGER I,IX,IY |
24 | 1 | pfleura2 | * .. |
25 | 1 | pfleura2 | * .. Intrinsic Functions .. |
26 | 1 | pfleura2 | INTRINSIC CONJG |
27 | 1 | pfleura2 | * .. |
28 | 1 | pfleura2 | CTEMP = (0.0,0.0) |
29 | 1 | pfleura2 | CDOTC = (0.0,0.0) |
30 | 1 | pfleura2 | IF (N.LE.0) RETURN |
31 | 1 | pfleura2 | IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20 |
32 | 1 | pfleura2 | * |
33 | 1 | pfleura2 | * code for unequal increments or equal increments |
34 | 1 | pfleura2 | * not equal to 1 |
35 | 1 | pfleura2 | * |
36 | 1 | pfleura2 | IX = 1 |
37 | 1 | pfleura2 | IY = 1 |
38 | 1 | pfleura2 | IF (INCX.LT.0) IX = (-N+1)*INCX + 1 |
39 | 1 | pfleura2 | IF (INCY.LT.0) IY = (-N+1)*INCY + 1 |
40 | 1 | pfleura2 | DO 10 I = 1,N |
41 | 1 | pfleura2 | CTEMP = CTEMP + CONJG(CX(IX))*CY(IY) |
42 | 1 | pfleura2 | IX = IX + INCX |
43 | 1 | pfleura2 | IY = IY + INCY |
44 | 1 | pfleura2 | 10 CONTINUE |
45 | 1 | pfleura2 | CDOTC = CTEMP |
46 | 1 | pfleura2 | RETURN |
47 | 1 | pfleura2 | * |
48 | 1 | pfleura2 | * code for both increments equal to 1 |
49 | 1 | pfleura2 | * |
50 | 1 | pfleura2 | 20 DO 30 I = 1,N |
51 | 1 | pfleura2 | CTEMP = CTEMP + CONJG(CX(I))*CY(I) |
52 | 1 | pfleura2 | 30 CONTINUE |
53 | 1 | pfleura2 | CDOTC = CTEMP |
54 | 1 | pfleura2 | RETURN |
55 | 1 | pfleura2 | END |