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LAPACK 3.3.1
Linear Algebra PACKage
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LAPACK 3.3.1
Linear Algebra PACKage
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00001 SUBROUTINE CCHKBK( NIN, NOUT ) 00002 * 00003 * -- LAPACK test routine (version 3.1) -- 00004 * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. 00005 * November 2006 00006 * 00007 * .. Scalar Arguments .. 00008 INTEGER NIN, NOUT 00009 * .. 00010 * 00011 * Purpose 00012 * ======= 00013 * 00014 * CCHKBK tests CGEBAK, a routine for backward transformation of 00015 * the computed right or left eigenvectors if the orginal matrix 00016 * was preprocessed by balance subroutine CGEBAL. 00017 * 00018 * Arguments 00019 * ========= 00020 * 00021 * NIN (input) INTEGER 00022 * The logical unit number for input. NIN > 0. 00023 * 00024 * NOUT (input) INTEGER 00025 * The logical unit number for output. NOUT > 0. 00026 * 00027 * ====================================================================== 00028 * 00029 * .. Parameters .. 00030 INTEGER LDE 00031 PARAMETER ( LDE = 20 ) 00032 REAL ZERO 00033 PARAMETER ( ZERO = 0.0E0 ) 00034 * .. 00035 * .. Local Scalars .. 00036 INTEGER I, IHI, ILO, INFO, J, KNT, N, NINFO 00037 REAL EPS, RMAX, SAFMIN, VMAX, X 00038 COMPLEX CDUM 00039 * .. 00040 * .. Local Arrays .. 00041 INTEGER LMAX( 2 ) 00042 REAL SCALE( LDE ) 00043 COMPLEX E( LDE, LDE ), EIN( LDE, LDE ) 00044 * .. 00045 * .. External Functions .. 00046 REAL SLAMCH 00047 EXTERNAL SLAMCH 00048 * .. 00049 * .. External Subroutines .. 00050 EXTERNAL CGEBAK 00051 * .. 00052 * .. Intrinsic Functions .. 00053 INTRINSIC ABS, AIMAG, MAX, REAL 00054 * .. 00055 * .. Statement Functions .. 00056 REAL CABS1 00057 * .. 00058 * .. Statement Function definitions .. 00059 CABS1( CDUM ) = ABS( REAL( CDUM ) ) + ABS( AIMAG( CDUM ) ) 00060 * .. 00061 * .. Executable Statements .. 00062 * 00063 LMAX( 1 ) = 0 00064 LMAX( 2 ) = 0 00065 NINFO = 0 00066 KNT = 0 00067 RMAX = ZERO 00068 EPS = SLAMCH( 'E' ) 00069 SAFMIN = SLAMCH( 'S' ) 00070 * 00071 10 CONTINUE 00072 * 00073 READ( NIN, FMT = * )N, ILO, IHI 00074 IF( N.EQ.0 ) 00075 $ GO TO 60 00076 * 00077 READ( NIN, FMT = * )( SCALE( I ), I = 1, N ) 00078 DO 20 I = 1, N 00079 READ( NIN, FMT = * )( E( I, J ), J = 1, N ) 00080 20 CONTINUE 00081 * 00082 DO 30 I = 1, N 00083 READ( NIN, FMT = * )( EIN( I, J ), J = 1, N ) 00084 30 CONTINUE 00085 * 00086 KNT = KNT + 1 00087 CALL CGEBAK( 'B', 'R', N, ILO, IHI, SCALE, N, E, LDE, INFO ) 00088 * 00089 IF( INFO.NE.0 ) THEN 00090 NINFO = NINFO + 1 00091 LMAX( 1 ) = KNT 00092 END IF 00093 * 00094 VMAX = ZERO 00095 DO 50 I = 1, N 00096 DO 40 J = 1, N 00097 X = CABS1( E( I, J )-EIN( I, J ) ) / EPS 00098 IF( CABS1( E( I, J ) ).GT.SAFMIN ) 00099 $ X = X / CABS1( E( I, J ) ) 00100 VMAX = MAX( VMAX, X ) 00101 40 CONTINUE 00102 50 CONTINUE 00103 * 00104 IF( VMAX.GT.RMAX ) THEN 00105 LMAX( 2 ) = KNT 00106 RMAX = VMAX 00107 END IF 00108 * 00109 GO TO 10 00110 * 00111 60 CONTINUE 00112 * 00113 WRITE( NOUT, FMT = 9999 ) 00114 9999 FORMAT( 1X, '.. test output of CGEBAK .. ' ) 00115 * 00116 WRITE( NOUT, FMT = 9998 )RMAX 00117 9998 FORMAT( 1X, 'value of largest test error = ', E12.3 ) 00118 WRITE( NOUT, FMT = 9997 )LMAX( 1 ) 00119 9997 FORMAT( 1X, 'example number where info is not zero = ', I4 ) 00120 WRITE( NOUT, FMT = 9996 )LMAX( 2 ) 00121 9996 FORMAT( 1X, 'example number having largest error = ', I4 ) 00122 WRITE( NOUT, FMT = 9995 )NINFO 00123 9995 FORMAT( 1X, 'number of examples where info is not 0 = ', I4 ) 00124 WRITE( NOUT, FMT = 9994 )KNT 00125 9994 FORMAT( 1X, 'total number of examples tested = ', I4 ) 00126 * 00127 RETURN 00128 * 00129 * End of CCHKBK 00130 * 00131 END
1.7.3 
