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izamax.f
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*> \brief \b IZAMAX
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*
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* =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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* http://www.netlib.org/lapack/explore-html/
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*
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* Definition:
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* ===========
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*
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* INTEGER FUNCTION IZAMAX(N,ZX,INCX)
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*
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* .. Scalar Arguments ..
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* INTEGER INCX,N
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* ..
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* .. Array Arguments ..
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* COMPLEX*16 ZX(*)
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* ..
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*
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*
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*> \par Purpose:
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* =============
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*>
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*> \verbatim
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*>
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*> IZAMAX finds the index of the first element having maximum |Re(.)| + |Im(.)|
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*> \endverbatim
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*
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* Authors:
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* ========
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*
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*> \author Univ. of Tennessee
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*> \author Univ. of California Berkeley
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*> \author Univ. of Colorado Denver
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*> \author NAG Ltd.
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*
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*> \date December 2016
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*
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*> \ingroup aux_blas
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*
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*> \par Further Details:
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* =====================
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*>
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*> \verbatim
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*>
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*> jack dongarra, 1/15/85.
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*> modified 3/93 to return if incx .le. 0.
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*> modified 12/3/93, array(1) declarations changed to array(*)
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*> \endverbatim
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*>
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* =====================================================================
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INTEGER
FUNCTION
izamax
(N,ZX,INCX)
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*
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* -- Reference BLAS level1 routine (version 3.7.0) --
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* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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* December 2016
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*
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* .. Scalar Arguments ..
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INTEGER
INCX,N
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* ..
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* .. Array Arguments ..
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COMPLEX*16
ZX(*)
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* ..
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*
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* =====================================================================
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*
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* .. Local Scalars ..
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DOUBLE PRECISION
DMAX
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INTEGER
I,IX
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* ..
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* .. External Functions ..
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DOUBLE PRECISION
DCABS1
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EXTERNAL
dcabs1
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* ..
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izamax
= 0
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IF
(n.LT.1 .OR. incx.LE.0)
RETURN
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izamax
= 1
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IF
(n.EQ.1)
RETURN
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IF
(incx.EQ.1)
THEN
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*
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* code for increment equal to 1
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*
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dmax = dcabs1(zx(1))
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DO
i = 2,n
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IF
(dcabs1(zx(i)).GT.dmax)
THEN
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izamax
= i
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dmax = dcabs1(zx(i))
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END IF
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END DO
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ELSE
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*
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* code for increment not equal to 1
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*
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ix = 1
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dmax = dcabs1(zx(1))
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ix = ix + incx
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DO
i = 2,n
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IF
(dcabs1(zx(ix)).GT.dmax)
THEN
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izamax
= i
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dmax = dcabs1(zx(ix))
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END IF
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ix = ix + incx
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END DO
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END IF
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RETURN
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END
izamax
integer function izamax(N, ZX, INCX)
IZAMAX
Definition:
izamax.f:53
BLAS
SRC
izamax.f
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