1: INTEGER FUNCTION IDAMAX(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: * IDAMAX finds the index of element having max. absolute value.
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 DMAX
25: INTEGER I,IX
26: * ..
27: * .. Intrinsic Functions ..
28: INTRINSIC DABS
29: * ..
30: IDAMAX = 0
31: IF (N.LT.1 .OR. INCX.LE.0) RETURN
32: IDAMAX = 1
33: IF (N.EQ.1) RETURN
34: IF (INCX.EQ.1) THEN
35: *
36: * code for increment equal to 1
37: *
38: DMAX = DABS(DX(1))
39: DO I = 2,N
40: IF (DABS(DX(I)).GT.DMAX) THEN
41: IDAMAX = I
42: DMAX = DABS(DX(I))
43: END IF
44: END DO
45: ELSE
46: *
47: * code for increment not equal to 1
48: *
49: IX = 1
50: DMAX = DABS(DX(1))
51: IX = IX + INCX
52: DO I = 2,N
53: IF (DABS(DX(IX)).GT.DMAX) THEN
54: IDAMAX = I
55: DMAX = DABS(DX(IX))
56: END IF
57: IX = IX + INCX
58: END DO
59: END IF
60: RETURN
61: END
CVSweb interface <joel.bertrand@systella.fr>