C******************************************************************************
C FILE: arit03.f
C DESCRIPTION:
C   Demonstrates factorization 
C******************************************************************************
	PROGRAM arit03

	IMPLICIT NONE
	INTEGER ARRAY_SIZE
	PARAMETER(ARRAY_SIZE = 1000000)
        REAL EPSILON, FFACTOR
	PARAMETER(EPSILON = 2.45)
	PARAMETER(FFACTOR = 0.337)
	INTEGER	I
        INTEGER(8) T1, T2, IRTC
        REAL A(ARRAY_SIZE), AA(ARRAY_SIZE)
        REAL B(ARRAY_SIZE), BB(ARRAY_SIZE)
        REAL C(ARRAY_SIZE), CC(ARRAY_SIZE)
        REAL D(ARRAY_SIZE), DD(ARRAY_SIZE)
        REAL F, FF, X, XX

C       Initialization
        DO I=1, ARRAY_SIZE
          A(I) = I*1.0
          B(I) = I*2.0
          C(I) = I*3.0
          D(I) = I*4.0
          AA(I) = I*1.0
          BB(I) = I*2.0
          CC(I) = I*3.0
          DD(I) = I*4.0
        ENDDO

C*****************************************************************************
C*				Untuned Loop			             *
C*****************************************************************************
        T1 = IRTC()

        DO I=1,ARRAY_SIZE
           F = I/EPSILON * FFACTOR
           X = F*A(I) + F*B(I) + F*C(I) + F*D(I)
        ENDDO 

        T2 = IRTC()
        WRITE(*,*)'Untuned loop took', (T2-T1)/1000000, 'msec'

C*****************************************************************************
C*				Tuned Loop				     *
C*****************************************************************************
        T1 = IRTC()

        DO I=1,ARRAY_SIZE
           FF = I/EPSILON * FFACTOR
           XX = FF*(AA(I) + BB(I) + CC(I) + DD(I))
        ENDDO 

        T2 = IRTC()
        WRITE(*,*)'Tuned loop took', (T2-T1)/1000000, 'msec'

C       Need to actually use the results of the calculations or else the
C       optimizing compiler may just skip doing them...so we'll just
C       print them.  This will force the optimizer to actually do the work.
        PRINT *, X, XX

999   end