rref returns wrong results for sparse matrices
Nils Bluthgen
nils.bluthgen at manchester.ac.uk
Sun Mar 2 11:32:20 CST 2008
Bug report for Octave 3.0.0 configured for i386-apple-darwin8.9.1
Description:
-----------
Calculation of the reduced row echelon form with rref.m gives
different results for sparse and full matrices.
Repeat-By:
---------
A=[1 2 3 4; 2 3 4 5; 2 3 4 2]
rref(A)
full(rref(sparse(A)))
Fix:
---
There is a workaround by calling rref(full(A)), but this is obviously
not a good solution
Configuration (please do not edit this section):
-----------------------------------------------
uname output: Darwin Nils-Bluthgens-Laptop.local 8.11.1 Darwin
Kernel Version 8.11.1: Wed Oct 10 18\
:23:28 PDT 2007; root:xnu-792.25.20~1/RELEASE_I386 i386 i386
configure opts: 'CC=gcc -O3 -ftree-vectorize -fforce-addr -
march=i686 -mfpmath=sse,387 -mieee-fp -ms\
se3 -msse2 -msse -mmmx' 'CPP=gcc -O3 -ftree-vectorize -fforce-addr -
march=i686 -mfpmath=sse,387 -mieee\
-fp -msse3 -msse2 -msse -mmmx -E' 'CXX=g++ -O3 -ftree-vectorize -
fforce-addr -march=i686 -mfpmath=sse,\
387 -mieee-fp -msse3 -msse2 -msse -mmmx' 'CFLAGS=' 'CPPFLAGS='
'CXXFLAGS=' 'LDFLAGS=' '--prefix=/tmp/de\
pendencies-i386' '' 'F77=fort77 -O3 -ftree-vectorize -fforce-addr -
march=i686 -mfpmath=sse,387 -mieee-f\
p -msse3 -msse2 -msse -mmmx' 'FLIBS=-lf2c' 'FFLAGS=' '--enable-
shared' 'host_alias=i386-apple-darwin8.9\
.1'
Fortran compiler: fort77 -O3 -ftree-vectorize -fforce-addr -
march=i686 -mfpmath=sse,387 -mieee-fp -msse\
3 -msse2 -msse -mmmx
FFLAGS:
F2C: @F2C@
F2CFLAGS: @F2CFLAGS@
FLIBS: -lf2c
CPPFLAGS: -I/tmp/dependencies-i386/include
INCFLAGS: -I. -I. -I./liboctave -I./src -I./libcruft/misc
C compiler: gcc -O3 -ftree-vectorize -fforce-addr -march=i686 -
mfpmath=sse,387 -mieee-fp -msse3 \
-msse2 -msse -mmmx, version 4.0.1 (Apple Computer, Inc. build 5367)
CFLAGS:
CPICFLAG: -fPIC
C++ compiler: g++ -O3 -ftree-vectorize -fforce-addr -march=i686 -
mfpmath=sse,387 -mieee-fp -msse3 \
-msse2 -msse -mmmx, version 4.0.1
CXXFLAGS:
CXXPICFLAG: -fPIC
LD_CXX: g++ -O3 -ftree-vectorize -fforce-addr -march=i686 -
mfpmath=sse,387 -mieee-fp -msse3 \
-msse2 -msse -mmmx
LDFLAGS:
LIBFLAGS: -L.
RLD_FLAG:
BLAS_LIBS: -Wl,-framework -Wl,vecLib
FFTW_LIBS: -lfftw3
LIBS: -lreadline -lncurses -lhdf5 -lz -lm
LEXLIB:
LIBGLOB:
SED: /usr/bin/sed
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-DHAVE_GETRUSAGE=1 -DHAVE_TIMES=1 -DYYTEXT_POINTER=1
-DGNUPLOT_BINARY="gnuplot"
User-preferences (please do not edit this section):
--------------------------------------------------
EDITOR = emacs
EXEC_PATH = /Applications/Octave.app/Contents/Resources/libexec/
octave/3.0.0/site/exec/i386-apple-dar\
win8.9.1:/Applications/Octave.app/Contents/Resources/libexec/octave/
api-v32/site/exec/i386-apple-darwin\
8.9.1:/Applications/Octave.app/Contents/Resources/libexec/octave/site/
exec/i386-apple-darwin8.9.1:/Appl\
ications/Octave.app/Contents/Resources/libexec/octave/3.0.0/exec/i386-
apple-darwin8.9.1:/Applications/O\
ctave.app/Contents/Resources/bin:/Applications/Octave.app/Contents/
Resources/bin:/sw/bin:/sw/sbin:/opt/\
local/bin:/opt/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/texbin:/
usr/local/bin:/Applications/Octave\
.app/Contents/Resources/bin/:/usr/X11R6/bin
IMAGE_PATH = .:/Applications/Octave.app/Contents/Resources/share/
octave/3.0.0/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 =
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 = /Users/nils/.octave_hist
history_size = 1024
ignore_function_time_stamp = system
info_file = /Applications/Octave.app/Contents/Resources/info/
octave.info
info_program = info
makeinfo_program = makeinfo
max_recursion_depth = 256
output_max_field_width = 5
output_precision = 5
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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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