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INTEGER FUNCTION IZMAX1( N, CX, INCX )
*
* -- LAPACK auxiliary routine (version 3.1) --
* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
* November 2006
*
* .. Scalar Arguments ..
INTEGER INCX, N
* ..
* .. Array Arguments ..
COMPLEX*16 CX( * )
* ..
*
* Purpose
* =======
*
* IZMAX1 finds the index of the element whose real part has maximum
* absolute value.
*
* Based on IZAMAX from Level 1 BLAS.
* The change is to use the 'genuine' absolute value.
*
* Contributed by Nick Higham for use with ZLACON.
*
* Arguments
* =========
*
* N (input) INTEGER
* The number of elements in the vector CX.
*
* CX (input) COMPLEX*16 array, dimension (N)
* The vector whose elements will be summed.
*
* INCX (input) INTEGER
* The spacing between successive values of CX. INCX >= 1.
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I, IX
DOUBLE PRECISION SMAX
COMPLEX*16 ZDUM
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS
* ..
* .. Statement Functions ..
DOUBLE PRECISION CABS1
* ..
* .. Statement Function definitions ..
*
* NEXT LINE IS THE ONLY MODIFICATION.
CABS1( ZDUM ) = ABS( ZDUM )
* ..
* .. Executable Statements ..
*
IZMAX1 = 0
IF( N.LT.1 )
$ RETURN
IZMAX1 = 1
IF( N.EQ.1 )
$ RETURN
IF( INCX.EQ.1 )
$ GO TO 30
*
* CODE FOR INCREMENT NOT EQUAL TO 1
*
IX = 1
SMAX = CABS1( CX( 1 ) )
IX = IX + INCX
DO 20 I = 2, N
IF( CABS1( CX( IX ) ).LE.SMAX )
$ GO TO 10
IZMAX1 = I
SMAX = CABS1( CX( IX ) )
10 CONTINUE
IX = IX + INCX
20 CONTINUE
RETURN
*
* CODE FOR INCREMENT EQUAL TO 1
*
30 CONTINUE
SMAX = CABS1( CX( 1 ) )
DO 40 I = 2, N
IF( CABS1( CX( I ) ).LE.SMAX )
$ GO TO 40
IZMAX1 = I
SMAX = CABS1( CX( I ) )
40 CONTINUE
RETURN
*
* End of IZMAX1
*
END
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