1: DOUBLE PRECISION FUNCTION DASUM(N,DX,INCX)
2: * .. Scalar Arguments ..
3: INTEGER INCX,N
4: * ..
5: * .. Array Arguments ..
6: DOUBLE PRECISION DX(*)
7: * ..
8: *
9: * Purpose
10: * =======
11: *
12: * DASUM takes the sum of the absolute values.
13: *
14: * Further Details
15: * ===============
16: *
17: * jack dongarra, linpack, 3/11/78.
18: * modified 3/93 to return if incx .le. 0.
19: * modified 12/3/93, array(1) declarations changed to array(*)
20: *
21: * =====================================================================
22: *
23: * .. Local Scalars ..
24: DOUBLE PRECISION DTEMP
25: INTEGER I,M,MP1,NINCX
26: * ..
27: * .. Intrinsic Functions ..
28: INTRINSIC DABS,MOD
29: * ..
30: DASUM = 0.0d0
31: DTEMP = 0.0d0
32: IF (N.LE.0 .OR. INCX.LE.0) RETURN
33: IF (INCX.EQ.1) THEN
34: * code for increment equal to 1
35: *
36: *
37: * clean-up loop
38: *
39: M = MOD(N,6)
40: IF (M.NE.0) THEN
41: DO I = 1,M
42: DTEMP = DTEMP + DABS(DX(I))
43: END DO
44: IF (N.LT.6) THEN
45: DASUM = DTEMP
46: RETURN
47: END IF
48: END IF
49: MP1 = M + 1
50: DO I = MP1,N,6
51: DTEMP = DTEMP + DABS(DX(I)) + DABS(DX(I+1)) +
52: $ DABS(DX(I+2)) + DABS(DX(I+3)) +
53: $ DABS(DX(I+4)) + DABS(DX(I+5))
54: END DO
55: ELSE
56: *
57: * code for increment not equal to 1
58: *
59: NINCX = N*INCX
60: DO I = 1,NINCX,INCX
61: DTEMP = DTEMP + DABS(DX(I))
62: END DO
63: END IF
64: DASUM = DTEMP
65: RETURN
66: END
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