INTEGER FUNCTION IDAMAX(N,DX,INCX) * .. Scalar Arguments .. INTEGER INCX,N * .. * .. Array Arguments .. DOUBLE PRECISION DX(*) * .. * * Purpose * ======= * * IDAMAX finds the index of element having max. absolute value. * * Further Details * =============== * * jack dongarra, linpack, 3/11/78. * 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 * .. * .. Intrinsic Functions .. INTRINSIC DABS * .. IDAMAX = 0 IF (N.LT.1 .OR. INCX.LE.0) RETURN IDAMAX = 1 IF (N.EQ.1) RETURN IF (INCX.EQ.1) GO TO 20 * * code for increment not equal to 1 * IX = 1 DMAX = DABS(DX(1)) IX = IX + INCX DO 10 I = 2,N IF (DABS(DX(IX)).LE.DMAX) GO TO 5 IDAMAX = I DMAX = DABS(DX(IX)) 5 IX = IX + INCX 10 CONTINUE RETURN * * code for increment equal to 1 * 20 DMAX = DABS(DX(1)) DO 30 I = 2,N IF (DABS(DX(I)).LE.DMAX) GO TO 30 IDAMAX = I DMAX = DABS(DX(I)) 30 CONTINUE RETURN END