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C
C SPDX-License-Identifier: BSD-3-Clause
C
* MB02SD EXAMPLE PROGRAM TEXT
*
* .. Parameters ..
DOUBLE PRECISION ZERO
PARAMETER ( ZERO = 0.0D0 )
INTEGER NIN, NOUT
PARAMETER ( NIN = 5, NOUT = 6 )
INTEGER NMAX, NRHMAX
PARAMETER ( NMAX = 20, NRHMAX = 20 )
INTEGER LDB, LDH
PARAMETER ( LDB = NMAX, LDH = NMAX )
INTEGER LDWORK
PARAMETER ( LDWORK = 3*NMAX )
INTEGER LIWORK
PARAMETER ( LIWORK = NMAX )
* .. Local Scalars ..
DOUBLE PRECISION HNORM, RCOND
INTEGER I, INFO, INFO1, J, N, NRHS
CHARACTER*1 NORM, TRANS
* .. Local Arrays ..
DOUBLE PRECISION H(LDH,NMAX), B(LDB,NRHMAX), DWORK(LDWORK)
INTEGER IPIV(NMAX), IWORK(LIWORK)
* .. External Functions ..
DOUBLE PRECISION DLAMCH, DLANHS
EXTERNAL DLAMCH, DLANHS
* .. External Subroutines ..
EXTERNAL DLASET, MB02RD, MB02SD, MB02TD
* .. Executable Statements ..
*
WRITE ( NOUT, FMT = 99999 )
* Skip the heading in the data file and read in the data.
READ ( NIN, FMT = '()' )
READ ( NIN, FMT = * ) N, NRHS, NORM, TRANS
IF ( N.LT.0 .OR. N.GT.NMAX ) THEN
WRITE ( NOUT, FMT = 99994 ) N
ELSE
READ ( NIN, FMT = * ) ( ( H(I,J), J = 1,N ), I = 1,N )
IF ( NRHS.LT.0 .OR. NRHS.GT.NRHMAX ) THEN
WRITE ( NOUT, FMT = 99993 ) NRHS
ELSE
READ ( NIN, FMT = * ) ( ( B(I,J), J = 1,NRHS ), I = 1,N )
IF ( N.GT.2 )
$ CALL DLASET( 'Lower', N-2, N-2, ZERO, ZERO, H(3,1), LDH )
* Compute the LU factorization of the upper Hessenberg matrix.
CALL MB02SD( N, H, LDH, IPIV, INFO )
* Estimate the reciprocal condition number of the matrix.
HNORM = DLANHS( NORM, N, H, LDH, DWORK )
CALL MB02TD( NORM, N, HNORM, H, LDH, IPIV, RCOND, IWORK,
$ DWORK, INFO1 )
IF ( INFO.EQ.0 .AND. RCOND.GT.DLAMCH( 'Epsilon' ) ) THEN
* Solve the linear system.
CALL MB02RD( TRANS, N, NRHS, H, LDH, IPIV, B, LDB, INFO )
*
WRITE ( NOUT, FMT = 99997 )
ELSE
WRITE ( NOUT, FMT = 99998 ) INFO
END IF
DO 10 I = 1, N
WRITE ( NOUT, FMT = 99996 ) ( B(I,J), J = 1,NRHS )
10 CONTINUE
WRITE ( NOUT, FMT = 99995 ) RCOND
END IF
END IF
STOP
*
99999 FORMAT (' MB02SD EXAMPLE PROGRAM RESULTS',/1X)
99998 FORMAT (' INFO on exit from MB02SD = ',I2)
99997 FORMAT (' The solution matrix is ')
99996 FORMAT (20(1X,F8.4))
99995 FORMAT (/' Reciprocal condition number = ',D12.4)
99994 FORMAT (/' N is out of range.',/' N = ',I5)
99993 FORMAT (/' NRHS is out of range.',/' NRHS = ',I5)
END
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