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* MB03MD EXAMPLE PROGRAM TEXT
*
* .. Parameters ..
DOUBLE PRECISION ZERO
PARAMETER ( ZERO = 0.0D0 )
INTEGER NIN, NOUT
PARAMETER ( NIN = 5, NOUT = 6 )
INTEGER NMAX
PARAMETER ( NMAX = 20 )
* .. Local Scalars ..
DOUBLE PRECISION PIVMIN, RELTOL, SAFMIN, THETA, TOL
INTEGER I, INFO, IWARN, L, N
* .. Local Arrays ..
DOUBLE PRECISION E(NMAX-1), E2(NMAX-1), Q(NMAX), Q2(NMAX)
* .. External Functions ..
DOUBLE PRECISION DLAMCH
EXTERNAL DLAMCH
* .. External Subroutines ..
EXTERNAL MB03MD
* .. Intrinsic Functions ..
INTRINSIC MAX
* .. Executable Statements ..
*
WRITE ( NOUT, FMT = 99999 )
* Skip the heading in the data file and read the data.
READ ( NIN, FMT = '()' )
READ ( NIN, FMT = * ) N, THETA, L, TOL, RELTOL
IF ( N.LT.0 .OR. N.GT.NMAX ) THEN
WRITE ( NOUT, FMT = 99991 ) N
ELSE IF ( L.LT.0 .OR. L.GT.N ) THEN
WRITE ( NOUT, FMT = 99990 ) L
ELSE
READ ( NIN, FMT = * ) ( Q(I), I = 1,N )
READ ( NIN, FMT = * ) ( E(I), I = 1,N-1 )
* Print out the bidiagonal matrix J.
WRITE ( NOUT, FMT = 99997 )
DO 20 I = 1, N - 1
WRITE ( NOUT, FMT = 99996 ) I, I, Q(I), I, (I+1), E(I)
20 CONTINUE
WRITE ( NOUT, FMT = 99995 ) N, N, Q(N)
* Compute Q**2, E**2, and PIVMIN.
Q2(N) = Q(N)**2
PIVMIN = Q2(N)
DO 40 I = 1, N - 1
Q2(I) = Q(I)**2
E2(I) = E(I)**2
PIVMIN = MAX( PIVMIN, Q2(I), E2(I) )
40 CONTINUE
SAFMIN = DLAMCH( 'Safe minimum' )
PIVMIN = MAX( PIVMIN*SAFMIN, SAFMIN )
TOL = MAX( TOL, ZERO )
IF ( RELTOL.LE.ZERO )
$ RELTOL = DLAMCH( 'Base' )*DLAMCH( 'Epsilon' )
* Compute an upper bound THETA such that J has 3 singular values
* < = THETA.
CALL MB03MD( N, L, THETA, Q, E, Q2, E2, PIVMIN, TOL, RELTOL,
$ IWARN, INFO )
*
IF ( INFO.NE.0 ) THEN
WRITE ( NOUT, FMT = 99998 ) INFO
ELSE
IF ( IWARN.NE.0 ) WRITE ( NOUT, FMT = 99994 ) IWARN
WRITE ( NOUT, FMT = 99993 ) THETA
WRITE ( NOUT, FMT = 99992 ) L
END IF
END IF
STOP
*
99999 FORMAT (' MB03MD EXAMPLE PROGRAM RESULTS',/1X)
99998 FORMAT (' INFO on exit from MB03MD = ',I2)
99997 FORMAT (' The Bidiagonal Matrix J is',/)
99996 FORMAT (2(' (',I1,',',I1,') = ',F7.4,2X))
99995 FORMAT (' (',I1,',',I1,') = ',F7.4)
99994 FORMAT (' IWARN on exit from MB03MD = ',I2,/)
99993 FORMAT (/' The computed value of THETA is ',F7.4)
99992 FORMAT (/' J has ',I2,' singular values < = THETA')
99991 FORMAT (/' N is out of range.',/' N = ',I5)
99990 FORMAT (/' L is out of range.',/' L = ',I5)
END
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