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INTEGER FUNCTION IZAMAX(N,ZX,INCX)
* .. Scalar Arguments ..
INTEGER INCX,N
* ..
* .. Array Arguments ..
COMPLEX*16 ZX(*)
* ..
*
* Purpose
* =======
*
* IZAMAX finds the index of element having max. absolute value.
*
* Further Details
* ===============
*
* jack dongarra, 1/15/85.
* modified 3/93 to return if incx .le. 0.
* modified 12/3/93, array(1) declarations changed to array(*)
*
* =====================================================================
*
* .. Local Scalars ..
DOUBLE PRECISION DMAX
INTEGER I,IX
* ..
* .. External Functions ..
DOUBLE PRECISION DCABS1
EXTERNAL DCABS1
* ..
IZAMAX = 0
IF (N.LT.1 .OR. INCX.LE.0) RETURN
IZAMAX = 1
IF (N.EQ.1) RETURN
IF (INCX.EQ.1) THEN
*
* code for increment equal to 1
*
DMAX = DCABS1(ZX(1))
DO I = 2,N
IF (DCABS1(ZX(I)).GT.DMAX) THEN
IZAMAX = I
DMAX = DCABS1(ZX(I))
END IF
END DO
ELSE
*
* code for increment not equal to 1
*
IX = 1
DMAX = DCABS1(ZX(1))
IX = IX + INCX
DO I = 2,N
IF (DCABS1(ZX(IX)).GT.DMAX) THEN
IZAMAX = I
DMAX = DCABS1(ZX(IX))
END IF
IX = IX + INCX
END DO
END IF
RETURN
END
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