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PROGRAM TEST4
*
* -- LAPACK test routine (version 3.0) --
* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
* Courant Institute, Argonne National Lab, and Rice University
* September 30, 1994
*
* .. Parameters ..
INTEGER NMAX, ITS
PARAMETER ( NMAX = 100, ITS = 5000 )
* ..
* .. Local Scalars ..
INTEGER I, J
REAL ALPHA, AVG, T1, T2, TNOSEC
* ..
* .. Local Arrays ..
REAL X( NMAX ), Y( NMAX )
* ..
* .. External Functions ..
REAL SECOND
EXTERNAL SECOND
* ..
* .. Intrinsic Functions ..
INTRINSIC REAL
* ..
* .. Executable Statements ..
*
*
* Initialize X and Y
*
DO 10 I = 1, NMAX
X( I ) = REAL( 1 ) / REAL( I )
Y( I ) = REAL( NMAX-I ) / REAL( NMAX )
10 CONTINUE
ALPHA = 0.315
*
* Time 1,000,000 SAXPY operations
*
T1 = SECOND( )
DO 30 J = 1, ITS
DO 20 I = 1, NMAX
Y( I ) = Y( I ) + ALPHA*X( I )
20 CONTINUE
ALPHA = -ALPHA
30 CONTINUE
T2 = SECOND( )
WRITE( 6, 9999 )T2 - T1
IF( T2-T1.GT.0.0 ) THEN
WRITE( 6, 9998 )1.0 / ( T2-T1 )
ELSE
WRITE( 6, 9994 )
END IF
TNOSEC = T2 - T1
*
* Time 1,000,000 SAXPY operations with SECOND in the outer loop
*
T1 = SECOND( )
DO 50 J = 1, ITS
DO 40 I = 1, NMAX
Y( I ) = Y( I ) + ALPHA*X( I )
40 CONTINUE
ALPHA = -ALPHA
T2 = SECOND( )
50 CONTINUE
*
* Compute the time used in milliseconds used by an average call
* to SECOND.
*
WRITE( 6, 9997 )T2 - T1
AVG = ( ( T2-T1 ) - TNOSEC ) * 1000./REAL( ITS )
WRITE( 6, 9996 )AVG
*
* Compute the equivalent number of floating point operations used
* by an average call to SECOND.
*
IF( TNOSEC.GT.0.0 )
$ WRITE( 6, 9995 )1000.*AVG / TNOSEC
*
9999 FORMAT( ' Time for 1,000,000 SAXPY ops = ', G10.3, ' seconds' )
9998 FORMAT( ' SAXPY performance rate = ', G10.3, ' mflops ' )
9997 FORMAT( ' Including SECOND, time = ', G10.3, ' seconds' )
9996 FORMAT( ' Average time for SECOND = ', G10.3,
$ ' milliseconds' )
9995 FORMAT( ' Equivalent floating point ops = ', G10.3, ' ops' )
9994 FORMAT( ' *** Error: Time for operations was zero' )
CALL MYSUB(NMAX,X,Y)
END
SUBROUTINE MYSUB(N,X,Y)
INTEGER N
REAL X(N), Y(N)
RETURN
END
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