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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 SMAX
   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) GO TO 20
   36: *
   37: *        code for increment not equal to 1
   38: *
   39:       IX = 1
   40:       SMAX = DCABS1(ZX(1))
   41:       IX = IX + INCX
   42:       DO 10 I = 2,N
   43:           IF (DCABS1(ZX(IX)).LE.SMAX) GO TO 5
   44:           IZAMAX = I
   45:           SMAX = DCABS1(ZX(IX))
   46:     5     IX = IX + INCX
   47:    10 CONTINUE
   48:       RETURN
   49: *
   50: *        code for increment equal to 1
   51: *
   52:    20 SMAX = DCABS1(ZX(1))
   53:       DO 30 I = 2,N
   54:           IF (DCABS1(ZX(I)).LE.SMAX) GO TO 30
   55:           IZAMAX = I
   56:           SMAX = DCABS1(ZX(I))
   57:    30 CONTINUE
   58:       RETURN
   59:       END