CVM Class Library  8.1
This C++ class library encapsulates concepts of vector and different matrices including square, band, symmetric and hermitian ones in Euclidean space of real and complex numbers.
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izamax.f
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1 c BLAS routine missing in ACML and some other implementations
2 
3  integer function izamax(n,zx,incx)
4 c
5 c finds the index of element having max. absolute value.
6 c jack dongarra, 1/15/85.
7 c modified 3/93 to return if incx .le. 0.
8 c modified 12/3/93, array(1) declarations changed to array(*)
9 c
10  double complex zx(*)
11  double precision smax
12  integer i,incx,ix,n
13  double precision cdabs
14 c
15  izamax = 0
16  if( n.lt.1 .or. incx.le.0 )return
17  izamax = 1
18  if(n.eq.1)return
19  if(incx.eq.1)go to 20
20 c
21 c code for increment not equal to 1
22 c
23  ix = 1
24  smax = cdabs(zx(1))
25  ix = ix + incx
26  do 10 i = 2,n
27  if(cdabs(zx(ix)).le.smax) go to 5
28  izamax = i
29  smax = cdabs(zx(ix))
30  5 ix = ix + incx
31  10 continue
32  return
33 c
34 c code for increment equal to 1
35 c
36  20 smax = cdabs(zx(1))
37  do 30 i = 2,n
38  if(cdabs(zx(i)).le.smax) go to 30
39  izamax = i
40  smax = cdabs(zx(i))
41  30 continue
42  return
43  end
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