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    1:       INTEGER FUNCTION IZAMAX(N,ZX,INCX)
    2: *     .. Scalar Arguments ..
    3:       INTEGER INCX,N
    4: *     ..
    5: *     .. Array Arguments ..
    6:       DOUBLE COMPLEX ZX(*)
    7: *     ..
    8: *
    9: *  Purpose
   10: *  =======
   11: *
   12: *     IZAMAX finds the index of element having max. absolute value.
   13: *
   14: *  Further Details
   15: *  ===============
   16: *
   17: *     jack dongarra, 1/15/85.
   18: *     modified 3/93 to return if incx .le. 0.
   19: *     modified 12/3/93, array(1) declarations changed to array(*)
   20: *
   21: *  =====================================================================
   22: *
   23: *     .. Local Scalars ..
   24:       DOUBLE PRECISION DMAX
   25:       INTEGER I,IX
   26: *     ..
   27: *     .. External Functions ..
   28:       DOUBLE PRECISION DCABS1
   29:       EXTERNAL DCABS1
   30: *     ..
   31:       IZAMAX = 0
   32:       IF (N.LT.1 .OR. INCX.LE.0) RETURN
   33:       IZAMAX = 1
   34:       IF (N.EQ.1) RETURN
   35:       IF (INCX.EQ.1) THEN
   36: *
   37: *        code for increment equal to 1
   38: *
   39:          DMAX = DCABS1(ZX(1))
   40:          DO I = 2,N
   41:             IF (DCABS1(ZX(I)).GT.DMAX) THEN
   42:                IZAMAX = I
   43:                DMAX = DCABS1(ZX(I))
   44:             END IF
   45:          END DO
   46:       ELSE
   47: *
   48: *        code for increment not equal to 1
   49: *
   50:          IX = 1
   51:          DMAX = DCABS1(ZX(1))
   52:          IX = IX + INCX
   53:          DO I = 2,N
   54:             IF (DCABS1(ZX(IX)).GT.DMAX) THEN
   55:                IZAMAX = I
   56:                DMAX = DCABS1(ZX(IX))
   57:             END IF
   58:             IX = IX + INCX
   59:          END DO
   60:       END IF
   61:       RETURN
   62:       END