blob: 88741e7e21e6ff92cd0c79429a732780bf2074b9 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
INTEGER FUNCTION ISAMAX(N,SX,INCX)
* .. Scalar Arguments ..
INTEGER INCX,N
* ..
* .. Array Arguments ..
REAL SX(*)
* ..
*
* Purpose
* =======
*
* ISAMAX finds the index of element having max. absolute value.
*
* Further Details
* ===============
*
* jack dongarra, linpack, 3/11/78.
* modified 3/93 to return if incx .le. 0.
* modified 12/3/93, array(1) declarations changed to array(*)
*
* =====================================================================
*
* .. Local Scalars ..
REAL SMAX
INTEGER I,IX
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS
* ..
ISAMAX = 0
IF (N.LT.1 .OR. INCX.LE.0) RETURN
ISAMAX = 1
IF (N.EQ.1) RETURN
IF (INCX.EQ.1) GO TO 20
*
* code for increment not equal to 1
*
IX = 1
SMAX = ABS(SX(1))
IX = IX + INCX
DO 10 I = 2,N
IF (ABS(SX(IX)).LE.SMAX) GO TO 5
ISAMAX = I
SMAX = ABS(SX(IX))
5 IX = IX + INCX
10 CONTINUE
RETURN
*
* code for increment equal to 1
*
20 SMAX = ABS(SX(1))
DO 30 I = 2,N
IF (ABS(SX(I)).LE.SMAX) GO TO 30
ISAMAX = I
SMAX = ABS(SX(I))
30 CONTINUE
RETURN
END
|
