Division by zero in rat/rats

Wed Jun 11 02:55:46 CDT 2008

Bug report for Octave 3.0.0 configured for x86_64-pc-linux-gnu

Description:
-----------

The functions rat and rats should handle the special case of zero  
input, which it seems currently they do not do. As a result the user  
recieves a 'warning: division by zero' and wrong output.

Repeat-By:
---------

rat(0)
[p,q] = rat(0)
rats(0)

Fix:
---

It is possible to check whether the input is zero before calling  
rat/rats but this is tedious. The check should be incorporated in the  
beginning of rat.m.

Configuration (please do not edit this section):
-----------------------------------------------

uname output:     Linux serre 2.6.24-18-generic #1 SMP Wed May 28  
19:28:38 UTC 2008 x86_64 GNU/Linux
configure opts:   '--host=x86_64-linux-gnu' '--build=x86_64-linux-gnu'  
'--prefix=/usr' '--datadir=/usr/share' '--libdir=/usr/lib'  
'--libexecdir=/usr/lib' '--infodir=/usr/share/info'  
'--mandir=/usr/share/man' '--with-blas=-lblas-3gf'  
'--with-lapack=-llapackgf-3' '--with-hdf5' '--with-fftw'  
'--enable-shared' '--enable-rpath' '--disable-static'  
'build_alias=x86_64-linux-gnu' 'host_alias=x86_64-linux-gnu' 'CC=gcc'  
'CFLAGS=-g -O2' 'LDFLAGS=-Wl,-Bsymbolic-functions' 'CPPFLAGS='  
'CXX=g++' 'CXXFLAGS=-g -O2' 'F77=gfortran' 'FFLAGS=-g -O2'
Fortran compiler: gfortran
FFLAGS:           -O2
F2C:              @F2C@
F2CFLAGS:         @F2CFLAGS@
FLIBS:            -L/usr/lib/gcc/x86_64-linux-gnu/4.2.3  
-L/usr/lib/gcc/x86_64-linux-gnu/4.2.3/../../../../lib64  
-L/lib/../lib64 -L/usr/lib/../lib64  
-L/usr/lib/gcc/x86_64-linux-gnu/4.2.3/../../.. -lhdf5 -lz  
-lgfortranbegin -lgfortran -lm
CPPFLAGS:
INCFLAGS:         -I. -I. -I./liboctave -I./src -I./libcruft/misc
C compiler:       gcc, version 4.2.3 (Ubuntu 4.2.3-2ubuntu6)
CFLAGS:           -O2
CPICFLAG:         -fPIC
C++ compiler:     g++, version 4.2.3
CXXFLAGS:         -O2
CXXPICFLAG:       -fPIC
LD_CXX:           g++
LDFLAGS:
LIBFLAGS:         -L.
RLD_FLAG:         -Wl,-rpath -Wl,/usr/lib/octave-3.0.0
BLAS_LIBS:        -llapackgf-3 -lblas-3gf
FFTW_LIBS:        -lfftw3
LIBS:             -lreadline  -lncurses -ldl -lhdf5 -lz -lm
LEXLIB:
LIBGLOB:
SED:              /bin/sed
DEFS:

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   -DHAVE_GLOB_H=1 -DHAVE_FNMATCH_H=1 -DHAVE_FNMATCH=1 -DHAVE_GLOB=1
   -DHAVE_ATEXIT=1 -DHAVE_BASENAME=1 -DHAVE_BCOPY=1 -DHAVE_BZERO=1
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   -DHAVE_MKSTEMP=1 -DHAVE_ON_EXIT=1 -DHAVE_PIPE=1 -DHAVE_POLL=1
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   -DHAVE_SIGLONGJMP=1 -DHAVE_SIGPENDING=1 -DHAVE_SIGPROCMASK=1
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   -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_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
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   -DHAVE_ISNAN=1 -DHAVE_ISINF=1 -DHAVE_COPYSIGN=1 -DHAVE_DECL_SIGNBIT=1
   -DHAVE_ACOSH=1 -DHAVE_ASINH=1 -DHAVE_ATANH=1 -DHAVE_ERF=1 -DHAVE_ERFC=1
   -DHAVE_EXP2=1 -DHAVE_LOG2=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 -DGNUPLOT_BINARY="gnuplot"

User-preferences (please do not edit this section):
--------------------------------------------------

   EDITOR = emacs
   EXEC_PATH =  
/usr/lib/octave/3.0.0/site/exec/x86_64-pc-linux-gnu:/usr/lib/octave/api-v32/site/exec/x86_64-pc-linux-gnu:/usr/lib/octave/site/exec/x86_64-pc-linux-gnu:/usr/lib/octave/3.0.0/exec/x86_64-pc-linux-gnu:/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
   IMAGE_PATH = .:/usr/share/octave/3.0.0/imagelib
   PAGER = pager
   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
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   gnuplot_command_plot = pl
   gnuplot_command_replot = rep
   gnuplot_command_splot = sp
   gnuplot_command_title = t
   gnuplot_command_using = u
   gnuplot_command_with = w
   history_file = /home/nasko/.octave_hist
   history_size = 1024
   ignore_function_time_stamp = system
   info_file = /usr/share/info/octave3.0.info
   info_program = info
   makeinfo_program = makeinfo
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