1 REAL FUNCTION SDOT(N,SX,INCX,SY,INCY)
2 * .. Scalar Arguments ..
3 INTEGER INCX,INCY,N
4 * ..
5 * .. Array Arguments ..
6 REAL SX(*),SY(*)
7 * ..
8 *
9 * Purpose
10 * =======
11 *
12 * SDOT forms the dot product of two vectors.
13 * uses unrolled loops for increments equal to one.
14 *
15 * Further Details
16 * ===============
17 *
18 * jack dongarra, linpack, 3/11/78.
19 * modified 12/3/93, array(1) declarations changed to array(*)
20 *
21 * =====================================================================
22 *
23 * .. Local Scalars ..
24 REAL STEMP
25 INTEGER I,IX,IY,M,MP1
26 * ..
27 * .. Intrinsic Functions ..
28 INTRINSIC MOD
29 * ..
30 STEMP = 0.0e0
31 SDOT = 0.0e0
32 IF (N.LE.0) RETURN
33 IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
34 *
35 * code for both increments equal to 1
36 *
37 *
38 * clean-up loop
39 *
40 M = MOD(N,5)
41 IF (M.NE.0) THEN
42 DO I = 1,M
43 STEMP = STEMP + SX(I)*SY(I)
44 END DO
45 IF (N.LT.5) THEN
46 SDOT=STEMP
47 RETURN
48 END IF
49 END IF
50 MP1 = M + 1
51 DO I = MP1,N,5
52 STEMP = STEMP + SX(I)*SY(I) + SX(I+1)*SY(I+1) +
53 $ SX(I+2)*SY(I+2) + SX(I+3)*SY(I+3) + SX(I+4)*SY(I+4)
54 END DO
55 ELSE
56 *
57 * code for unequal increments or equal increments
58 * not equal to 1
59 *
60 IX = 1
61 IY = 1
62 IF (INCX.LT.0) IX = (-N+1)*INCX + 1
63 IF (INCY.LT.0) IY = (-N+1)*INCY + 1
64 DO I = 1,N
65 STEMP = STEMP + SX(IX)*SY(IY)
66 IX = IX + INCX
67 IY = IY + INCY
68 END DO
69 END IF
70 SDOT = STEMP
71 RETURN
72 END
2 * .. Scalar Arguments ..
3 INTEGER INCX,INCY,N
4 * ..
5 * .. Array Arguments ..
6 REAL SX(*),SY(*)
7 * ..
8 *
9 * Purpose
10 * =======
11 *
12 * SDOT forms the dot product of two vectors.
13 * uses unrolled loops for increments equal to one.
14 *
15 * Further Details
16 * ===============
17 *
18 * jack dongarra, linpack, 3/11/78.
19 * modified 12/3/93, array(1) declarations changed to array(*)
20 *
21 * =====================================================================
22 *
23 * .. Local Scalars ..
24 REAL STEMP
25 INTEGER I,IX,IY,M,MP1
26 * ..
27 * .. Intrinsic Functions ..
28 INTRINSIC MOD
29 * ..
30 STEMP = 0.0e0
31 SDOT = 0.0e0
32 IF (N.LE.0) RETURN
33 IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
34 *
35 * code for both increments equal to 1
36 *
37 *
38 * clean-up loop
39 *
40 M = MOD(N,5)
41 IF (M.NE.0) THEN
42 DO I = 1,M
43 STEMP = STEMP + SX(I)*SY(I)
44 END DO
45 IF (N.LT.5) THEN
46 SDOT=STEMP
47 RETURN
48 END IF
49 END IF
50 MP1 = M + 1
51 DO I = MP1,N,5
52 STEMP = STEMP + SX(I)*SY(I) + SX(I+1)*SY(I+1) +
53 $ SX(I+2)*SY(I+2) + SX(I+3)*SY(I+3) + SX(I+4)*SY(I+4)
54 END DO
55 ELSE
56 *
57 * code for unequal increments or equal increments
58 * not equal to 1
59 *
60 IX = 1
61 IY = 1
62 IF (INCX.LT.0) IX = (-N+1)*INCX + 1
63 IF (INCY.LT.0) IY = (-N+1)*INCY + 1
64 DO I = 1,N
65 STEMP = STEMP + SX(IX)*SY(IY)
66 IX = IX + INCX
67 IY = IY + INCY
68 END DO
69 END IF
70 SDOT = STEMP
71 RETURN
72 END