LAPACK  3.10.0
LAPACK: Linear Algebra PACKage

◆ icamax()

integer function icamax ( integer  N,
complex, dimension(*)  CX,
integer  INCX 
)

ICAMAX

Purpose:
    ICAMAX finds the index of the first element having maximum |Re(.)| + |Im(.)|
Parameters
[in]N
          N is INTEGER
         number of elements in input vector(s)
[in]CX
          CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
[in]INCX
          INCX is INTEGER
         storage spacing between elements of CX
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
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(*)

Definition at line 70 of file icamax.f.

71 *
72 * -- Reference BLAS level1 routine --
73 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
74 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
75 *
76 * .. Scalar Arguments ..
77  INTEGER INCX,N
78 * ..
79 * .. Array Arguments ..
80  COMPLEX CX(*)
81 * ..
82 *
83 * =====================================================================
84 *
85 * .. Local Scalars ..
86  REAL SMAX
87  INTEGER I,IX
88 * ..
89 * .. External Functions ..
90  REAL SCABS1
91  EXTERNAL scabs1
92 * ..
93  icamax = 0
94  IF (n.LT.1 .OR. incx.LE.0) RETURN
95  icamax = 1
96  IF (n.EQ.1) RETURN
97  IF (incx.EQ.1) THEN
98 *
99 * code for increment equal to 1
100 *
101  smax = scabs1(cx(1))
102  DO i = 2,n
103  IF (scabs1(cx(i)).GT.smax) THEN
104  icamax = i
105  smax = scabs1(cx(i))
106  END IF
107  END DO
108  ELSE
109 *
110 * code for increment not equal to 1
111 *
112  ix = 1
113  smax = scabs1(cx(1))
114  ix = ix + incx
115  DO i = 2,n
116  IF (scabs1(cx(ix)).GT.smax) THEN
117  icamax = i
118  smax = scabs1(cx(ix))
119  END IF
120  ix = ix + incx
121  END DO
122  END IF
123  RETURN
124 *
125 * End of ICAMAX
126 *
integer function icamax(N, CX, INCX)
ICAMAX
Definition: icamax.f:71
real function scabs1(Z)
SCABS1
Definition: scabs1.f:46
Here is the call graph for this function:
Here is the caller graph for this function: