dec2base test failure
Thorsten Meyer
thorsten.meyier at gmx.de
Wed Apr 15 12:21:26 CDT 2009
Ivan Sutoris wrote:
> Bug report for Octave 3.1.55 configured for i686-pc-linux-gnu
>
> Description:
> -----------
>
> After compiling development sources today (tip 9122:8ca06fd9c6ef), I
> have noticed test failure at dec2base function (computes string
> representation of number in other bases), which returned wrong result
> for this input:
>
> dec2base(125, 5)
> ans = 1044
>
> Correct result should be 1000 (125 = 5^3). Has anyone else encountered this?
>
> I think the problem happens at line 87, where expression
>
> power = ones (length (n), 1) * (base .^ (max_len-1 : -1 : 0));
>
> should evaluate to [125 25 5 1] (in this case, n=125, base=5,
> max_len=4), but the actual result deviates slightly:
>
> debug> power - [125 25 5 1]
> ans =
>
> 0.0000e+00 0.0000e+00 8.8818e-16 2.2204e-16
>
> This causes problem later at line 89, when digits are computed using
> division remainder (for example, compare results of rem(125,5) and
> rem(125, 5 + 10^-15)). I see that Jaroslav optimized scalar .^ range
> operations recently, so maybe this is related to those changes (I
> think this was not problem before)?.
>
>
> Fix:
> ---
>
> Quick fix would be to round result of problematic expression (see
> attached changeset), although I'm not sure if that is correct solution
> in general.
>
>
> Configuration (please do not edit this section):
> -----------------------------------------------
>
> uname output: Linux ivansml-laptop 2.6.26-1-686 #1 SMP Fri Mar 13
> 18:08:45 UTC 2009 i686 GNU/Linux
> configure opts: '--prefix=/home/ivansml/usr'
> Fortran compiler: gfortran
> FFLAGS: -O -mieee-fp
> F2C: @F2C@
> F2CFLAGS: @F2CFLAGS@
> FLIBS: -L/usr/lib/gcc/i486-linux-gnu/4.3.2
> -L/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../lib -L/lib/../lib
> -L/usr/lib/../lib -L/usr/lib/gcc/i486-linux-gnu/4.3.2/../../.. -lhdf5
> -lz -lgfortranbegin -lgfortran -lm
> CPPFLAGS:
> INCFLAGS: -I. -I. -I./liboctave -I./src -I./libcruft/misc
> C compiler: gcc, version 4.3.2 (Debian 4.3.2-1.1)
> CFLAGS: -g -O2
> CPICFLAG: -fPIC
> C++ compiler: g++, version 4.3.2
> CXXFLAGS: -g -O2
> CXXPICFLAG: -fPIC
> LD_CXX: g++
> LDFLAGS:
> LIBFLAGS: -L.
> RLD_FLAG: -Wl,-rpath -Wl,/home/ivansml/usr/lib/octave-3.1.55
> BLAS_LIBS: -llapack -lcblas -lf77blas -latlas
> FFTW_LIBS: -lfftw3 -lfftw3f
> LIBS: -lreadline -lncurses -ldl -lcblas -lf77blas -latlas
> -lhdf5 -lz -lm
> LEXLIB:
> LIBGLOB:
> SED: /bin/sed
> DEFS:
>
> -DPACKAGE_NAME="" -DPACKAGE_TARNAME="" -DPACKAGE_VERSION=""
> -DPACKAGE_STRING="" -DPACKAGE_BUGREPORT="" -DOCTAVE_SOURCE=1
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> -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -D__EXTENSIONS__=1
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> -DSEPCHAR_STR=":" -D__NO_MATH_INLINES=1 -DCXX_NEW_FRIEND_TEMPLATE_DECL=1
> -DCXX_ISO_COMPLIANT_LIBRARY=1 -DHAVE_X_WINDOWS=1 -DHAVE_LIBM=1
> -DHAVE_QHULL=1 -DHAVE_PCRE_COMPILE=1 -DHAVE_PCRE=1 -DHAVE_REGEXEC=1
> -DHAVE_REGEX=1 -DHAVE_ZLIB_H=1 -DHAVE_ZLIB=1 -DHAVE_HDF5_H=1 -DHAVE_HDF5=1
> -DHAVE_H5GGET_NUM_OBJS=1 -DHAVE_FFTW3=1 -DHAVE_GLPK_H=1 -DHAVE_GLPK=1
> -DHAVE_CURL_CURL_H=1 -DHAVE_CURL=1 -DHAVE_MAGICK=1 -DHAVE_GL_GL_H=1
> -DHAVE_GL_GLU_H=1 -DHAVE_OPENGL=1 -DHAVE_FTGL_FTGL_H=1 -DHAVE_FTGL=1
> -DHAVE_FLTK=1 -DHAVE_IEEE754_DATA_FORMAT=1 -DF77_FUNC(name,NAME)=name
> ## _ -DF77_FUNC_(name,NAME)=name ## _ -DHAVE_BLAS=1 -DHAVE_QRUPDATE=1
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> -DHAVE_UMFPACK=1 -DUMFPACK_SEPARATE_SPLIT=1 -DHAVE_SUITESPARSE_COLAMD_H=1
> -DHAVE_COLAMD=1 -DHAVE_SUITESPARSE_CCOLAMD_H=1 -DHAVE_CCOLAMD=1
> -DHAVE_SUITESPARSE_CHOLMOD_H=1 -DHAVE_CHOLMOD=1 -DHAVE_SUITESPARSE_CS_H=1
> -DHAVE_CXSPARSE=1 -DHAVE_ARPACK=1 -DHAVE_GETHOSTNAME=1 -DHAVE_GETPWNAM=1
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> -DSIZEOF_INT=4 -DSIZEOF_LONG=4 -DSIZEOF_LONG_LONG=8 -DHAVE_ALLOCA_H=1
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> -DHAVE_DUP2=1 -DHAVE_ENDGRENT=1 -DHAVE_ENDPWENT=1 -DHAVE_EXECVP=1
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> -DHAVE_FSTAT=1 -DHAVE_GETCWD=1 -DHAVE_GETEGID=1 -DHAVE_GETEUID=1
> -DHAVE_GETGID=1 -DHAVE_GETGRENT=1 -DHAVE_GETGRGID=1 -DHAVE_GETGRNAM=1
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> -DHAVE_GETPWUID=1 -DHAVE_GETTIMEOFDAY=1 -DHAVE_GETUID=1 -DHAVE_GETWD=1
> -DHAVE_KILL=1 -DHAVE_LGAMMA=1 -DHAVE_LGAMMAF=1 -DHAVE_LGAMMA_R=1
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> -DHAVE_LOG1PF=1 -DHAVE_LSTAT=1 -DHAVE_MEMMOVE=1 -DHAVE_MKDIR=1
> -DHAVE_MKFIFO=1 -DHAVE_MKSTEMP=1 -DHAVE_ON_EXIT=1 -DHAVE_PIPE=1
> -DHAVE_POLL=1 -DHAVE_PUTENV=1 -DHAVE_RAISE=1 -DHAVE_READLINK=1
> -DHAVE_REALPATH=1 -DHAVE_RENAME=1 -DHAVE_RINDEX=1 -DHAVE_RMDIR=1
> -DHAVE_ROUND=1 -DHAVE_ROUNDL=1 -DHAVE_SELECT=1 -DHAVE_SETGRENT=1
> -DHAVE_SETLOCALE=1 -DHAVE_SETPWENT=1 -DHAVE_SETVBUF=1 -DHAVE_SIGACTION=1
> -DHAVE_SIGLONGJMP=1 -DHAVE_SIGPENDING=1 -DHAVE_SIGPROCMASK=1
> -DHAVE_SIGSUSPEND=1 -DHAVE_SNPRINTF=1 -DHAVE_STAT=1 -DHAVE_STRCASECMP=1
> -DHAVE_STRDUP=1 -DHAVE_STRERROR=1 -DHAVE_STRNCASECMP=1 -DHAVE_STRPTIME=1
> -DHAVE_STRSIGNAL=1 -DHAVE_SYMLINK=1 -DHAVE_TEMPNAM=1 -DHAVE_TGAMMA=1
> -DHAVE_TGAMMAF=1 -DHAVE_TRUNC=1 -DHAVE_UMASK=1 -DHAVE_UNAME=1
> -DHAVE_UNLINK=1 -DHAVE_USLEEP=1 -DHAVE_UTIME=1 -DHAVE_VFPRINTF=1
> -DHAVE_VSPRINTF=1 -DHAVE_VSNPRINTF=1 -DHAVE_WAITPID=1 -DHAVE_STRFTIME=1
> -DHAVE_LIBDL=1 -DHAVE_DLOPEN=1 -DHAVE_DLSYM=1 -DHAVE_DLERROR=1
> -DHAVE_DLCLOSE=1 -DHAVE_DLOPEN_API=1 -DENABLE_DYNAMIC_LINKING=1
> -DHAVE_TIMEVAL=1 -DHAVE_CMATH_ISNAN=1 -DHAVE_CMATH_ISNANF=1
> -DHAVE_CMATH_ISINF=1 -DHAVE_CMATH_ISINFF=1 -DHAVE_CMATH_ISFINITE=1
> -DHAVE_CMATH_ISFINITEF=1 -DHAVE_FINITE=1 -DHAVE_ISNAN=1 -DHAVE_ISINF=1
> -DHAVE_COPYSIGN=1 -DHAVE_DECL_SIGNBIT=1 -DHAVE_ACOSH=1 -DHAVE_ACOSHF=1
> -DHAVE_ASINH=1 -DHAVE_ASINHF=1 -DHAVE_ATANH=1 -DHAVE_ATANHF=1
> -DHAVE_ERF=1 -DHAVE_ERFF=1 -DHAVE_ERFC=1 -DHAVE_ERFCF=1 -DHAVE_EXP2=1
> -DHAVE_EXP2F=1 -DHAVE_LOG2=1 -DHAVE_LOG2F=1 -DHAVE_HYPOTF=1
> -DHAVE_STRUCT_STAT_ST_BLKSIZE=1 -DHAVE_STRUCT_STAT_ST_BLOCKS=1
> -DHAVE_STRUCT_STAT_ST_RDEV=1 -DHAVE_STRUCT_TM_TM_ZONE=1
> -DHAVE_TM_ZONE=1 -DUSE_READLINE=1 -DEXCEPTION_IN_MATH=1 -DRETSIGTYPE=void
> -DHAVE_DECL_SYS_SIGLIST=1 -DHAVE_POSIX_SIGNALS=1 -DRETSIGTYPE_IS_VOID=1
> -DHAVE_GETRUSAGE=1 -DHAVE_TIMES=1 -DYYTEXT_POINTER=1
>
> User-preferences (please do not edit this section):
> --------------------------------------------------
>
> EDITOR = emacs
> EXEC_PATH = /home/ivansml/usr/libexec/octave/3.1.55/site/exec/i686-pc-linux-gnu:/home/ivansml/usr/libexec/octave/api-v37/site/exec/i686-pc-linux-gnu:/home/ivansml/usr/libexec/octave/site/exec/i686-pc-linux-gnu:/home/ivansml/usr/libexec/octave/3.1.55/exec/i686-pc-linux-gnu:/home/ivansml/usr/bin:/home/ivansml/bin:/usr/local/bin:/usr/bin:/bin:/usr/games
> IMAGE_PATH = .:/home/ivansml/usr/share/octave/3.1.55/imagelib
> PAGER = less
> PS1 = \s:\#>
> PS2 = >
> PS4 = +
> beep_on_error = 0
> completion_append_char =
> crash_dumps_octave_core = 1
> echo_executing_commands = 0
> fixed_point_format = 0
> gnuplot_binary = gnuplot
> # gnuplot_command_end = <no value or error in displaying it>
> # gnuplot_command_plot = <no value or error in displaying it>
> # gnuplot_command_replot = <no value or error in displaying it>
> # gnuplot_command_splot = <no value or error in displaying it>
> # gnuplot_command_title = <no value or error in displaying it>
> # gnuplot_command_using = <no value or error in displaying it>
> # gnuplot_command_with = <no value or error in displaying it>
> history_file = /home/ivansml/.octave_hist
> history_size = 1024
> ignore_function_time_stamp = system
> info_file = /home/ivansml/usr/share/info/octave.info
> info_program = info
> makeinfo_program = makeinfo
> max_recursion_depth = 256
> output_max_field_width = 5
> output_precision = 5
> page_output_immediately = 0
> page_screen_output = 1
> # print_answer_id_name = <no value or error in displaying it>
> print_empty_dimensions = 1
> save_precision = 16
> saving_history = 1
> sighup_dumps_octave_core = 1
> sigterm_dumps_octave_core = 1
> silent_functions = 0
> split_long_rows = 1
> string_fill_char =
> struct_levels_to_print = 2
> suppress_verbose_help_message = 0
>
>
> ------------------------------------------------------------------------
>
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You beat me by a few minutes in repoting this bug.
Regards
Thorsten
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