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LAPACK
3.4.1
LAPACK: Linear Algebra PACKage
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00001 *> \brief \b DCHKBK 00002 * 00003 * =========== DOCUMENTATION =========== 00004 * 00005 * Online html documentation available at 00006 * http://www.netlib.org/lapack/explore-html/ 00007 * 00008 * Definition: 00009 * =========== 00010 * 00011 * SUBROUTINE DCHKBK( NIN, NOUT ) 00012 * 00013 * .. Scalar Arguments .. 00014 * INTEGER NIN, NOUT 00015 * .. 00016 * 00017 * 00018 *> \par Purpose: 00019 * ============= 00020 *> 00021 *> \verbatim 00022 *> 00023 *> DCHKBK tests DGEBAK, a routine for backward transformation of 00024 *> the computed right or left eigenvectors if the orginal matrix 00025 *> was preprocessed by balance subroutine DGEBAL. 00026 *> \endverbatim 00027 * 00028 * Arguments: 00029 * ========== 00030 * 00031 *> \param[in] NIN 00032 *> \verbatim 00033 *> NIN is INTEGER 00034 *> The logical unit number for input. NIN > 0. 00035 *> \endverbatim 00036 *> 00037 *> \param[in] NOUT 00038 *> \verbatim 00039 *> NOUT is INTEGER 00040 *> The logical unit number for output. NOUT > 0. 00041 *> \endverbatim 00042 * 00043 * Authors: 00044 * ======== 00045 * 00046 *> \author Univ. of Tennessee 00047 *> \author Univ. of California Berkeley 00048 *> \author Univ. of Colorado Denver 00049 *> \author NAG Ltd. 00050 * 00051 *> \date November 2011 00052 * 00053 *> \ingroup double_eig 00054 * 00055 * ===================================================================== 00056 SUBROUTINE DCHKBK( NIN, NOUT ) 00057 * 00058 * -- LAPACK test routine (version 3.4.0) -- 00059 * -- LAPACK is a software package provided by Univ. of Tennessee, -- 00060 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 00061 * November 2011 00062 * 00063 * .. Scalar Arguments .. 00064 INTEGER NIN, NOUT 00065 * .. 00066 * 00067 * ====================================================================== 00068 * 00069 * .. Parameters .. 00070 INTEGER LDE 00071 PARAMETER ( LDE = 20 ) 00072 DOUBLE PRECISION ZERO 00073 PARAMETER ( ZERO = 0.0D0 ) 00074 * .. 00075 * .. Local Scalars .. 00076 INTEGER I, IHI, ILO, INFO, J, KNT, N, NINFO 00077 DOUBLE PRECISION EPS, RMAX, SAFMIN, VMAX, X 00078 * .. 00079 * .. Local Arrays .. 00080 INTEGER LMAX( 2 ) 00081 DOUBLE PRECISION E( LDE, LDE ), EIN( LDE, LDE ), SCALE( LDE ) 00082 * .. 00083 * .. External Functions .. 00084 DOUBLE PRECISION DLAMCH 00085 EXTERNAL DLAMCH 00086 * .. 00087 * .. External Subroutines .. 00088 EXTERNAL DGEBAK 00089 * .. 00090 * .. Intrinsic Functions .. 00091 INTRINSIC ABS, MAX 00092 * .. 00093 * .. Executable Statements .. 00094 * 00095 LMAX( 1 ) = 0 00096 LMAX( 2 ) = 0 00097 NINFO = 0 00098 KNT = 0 00099 RMAX = ZERO 00100 EPS = DLAMCH( 'E' ) 00101 SAFMIN = DLAMCH( 'S' ) 00102 * 00103 10 CONTINUE 00104 * 00105 READ( NIN, FMT = * )N, ILO, IHI 00106 IF( N.EQ.0 ) 00107 $ GO TO 60 00108 * 00109 READ( NIN, FMT = * )( SCALE( I ), I = 1, N ) 00110 DO 20 I = 1, N 00111 READ( NIN, FMT = * )( E( I, J ), J = 1, N ) 00112 20 CONTINUE 00113 * 00114 DO 30 I = 1, N 00115 READ( NIN, FMT = * )( EIN( I, J ), J = 1, N ) 00116 30 CONTINUE 00117 * 00118 KNT = KNT + 1 00119 CALL DGEBAK( 'B', 'R', N, ILO, IHI, SCALE, N, E, LDE, INFO ) 00120 * 00121 IF( INFO.NE.0 ) THEN 00122 NINFO = NINFO + 1 00123 LMAX( 1 ) = KNT 00124 END IF 00125 * 00126 VMAX = ZERO 00127 DO 50 I = 1, N 00128 DO 40 J = 1, N 00129 X = ABS( E( I, J )-EIN( I, J ) ) / EPS 00130 IF( ABS( E( I, J ) ).GT.SAFMIN ) 00131 $ X = X / ABS( E( I, J ) ) 00132 VMAX = MAX( VMAX, X ) 00133 40 CONTINUE 00134 50 CONTINUE 00135 * 00136 IF( VMAX.GT.RMAX ) THEN 00137 LMAX( 2 ) = KNT 00138 RMAX = VMAX 00139 END IF 00140 * 00141 GO TO 10 00142 * 00143 60 CONTINUE 00144 * 00145 WRITE( NOUT, FMT = 9999 ) 00146 9999 FORMAT( 1X, '.. test output of DGEBAK .. ' ) 00147 * 00148 WRITE( NOUT, FMT = 9998 )RMAX 00149 9998 FORMAT( 1X, 'value of largest test error = ', D12.3 ) 00150 WRITE( NOUT, FMT = 9997 )LMAX( 1 ) 00151 9997 FORMAT( 1X, 'example number where info is not zero = ', I4 ) 00152 WRITE( NOUT, FMT = 9996 )LMAX( 2 ) 00153 9996 FORMAT( 1X, 'example number having largest error = ', I4 ) 00154 WRITE( NOUT, FMT = 9995 )NINFO 00155 9995 FORMAT( 1X, 'number of examples where info is not 0 = ', I4 ) 00156 WRITE( NOUT, FMT = 9994 )KNT 00157 9994 FORMAT( 1X, 'total number of examples tested = ', I4 ) 00158 * 00159 RETURN 00160 * 00161 * End of DCHKBK 00162 * 00163 END