[sage-devel] Re: Multivariate polynomial factoring and bug(?)
On Saturday, 12 November 2016 08:14:25 UTC+1, Bill Hart wrote: > > > I wonder if it is sometimes worth taking the gcd G of the leading > coefficients of the original primitive polynomials and then taking the gcd > of that with the leading coefficient L of the result of the psr process, > and then trying L/G as the possible content. Of course one would only want > to try that if other tricks have failed to find the content. > > Sorry, meant: I wonder if it is sometimes worth taking the gcd G of the leading coefficients of the original primitive polynomials and then taking the gcd H of that with the leading coefficient L of the result of the psr process, and then trying L/H as the possible content. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Multivariate polynomial factoring and bug(?)
On Saturday, 12 November 2016 07:42:53 UTC+1, parisse wrote: > > > > Le samedi 12 novembre 2016 06:50:45 UTC+1, Bill Hart a écrit : >> >> >> >> Looking how the content (188 monomials) is computed, it's done by exact >>> divisions only (it's the leading coefficient up to trivial coefficients). >>> >> >> Can you give me a hint where this is implemented. I didn't find this >> yesterday. It's a nice trick. >> >> > It's in gausspol.cc, around line 4100 "Trying p/lgcd(p)) as gcd". If the > degree of the gcd of the evaluation is the same as the degree of one of the > arguments, then there is a very good chance that the gcd itself is one of > the argument. > I think it's a good idea to look at sources, most papers do not describe > tricks, and some papers/books are written by people that did not really > implement, which means they miss some points. > Thanks. I agree, sometimes source code is extremely useful to have. I've implemented something similar now and it works! By the way, the times I reported the other day are not correct. At the time I didn't have code implemented for removing content at the end, and I also had some bugs in my exact division code. Once I implemented code to remove the final content, I was horrified to discover it was almost all of the runtime. I wonder if it is sometimes worth taking the gcd G of the leading coefficients of the original primitive polynomials and then taking the gcd of that with the leading coefficient L of the result of the psr process, and then trying L/G as the possible content. Of course one would only want to try that if other tricks have failed to find the content. Bill. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Multivariate polynomial factoring and bug(?)
Le samedi 12 novembre 2016 06:50:45 UTC+1, Bill Hart a écrit : > > > > Looking how the content (188 monomials) is computed, it's done by exact >> divisions only (it's the leading coefficient up to trivial coefficients). >> > > Can you give me a hint where this is implemented. I didn't find this > yesterday. It's a nice trick. > > It's in gausspol.cc, around line 4100 "Trying p/lgcd(p)) as gcd". If the degree of the gcd of the evaluation is the same as the degree of one of the arguments, then there is a very good chance that the gcd itself is one of the argument. I think it's a good idea to look at sources, most papers do not describe tricks, and some papers/books are written by people that did not really implement, which means they miss some points. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Multivariate polynomial factoring and bug(?)
By the way, yesterday I implemented algorithm 3 in Brown's paper on psrgcd. I didn't notice any improvement, so I abandoned it. I wasn't able to decide whether algorithm 4 is actually an algorithm, let alone whether it would be worth implementing, so I didn't bother with that. Bill. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Multivariate polynomial factoring and bug(?)
On Friday, 11 November 2016 21:00:49 UTC+1, parisse wrote: > > > > Le vendredi 11 novembre 2016 07:03:46 UTC+1, Bill Hart a écrit : >> >> I assume you are using the modular algorithm to remove the final lot of >> content at the end of the psr algorithm. Otherwise the algorithm takes >> quite a long time, since even if we remove the known factors of the content >> along the way, as specified by the algorithm, the result is far from >> primitive, and so computing the content in the final step of the algorithm >> takes a long time. >> >> Bill. >> > > I'm using a trick for the last step of psrgcd: since the gcd should be of > degree 6 wrt y (obtained by evaluation of other variables), when I have the > remainder of degree 6 (1276 monomials), I check that the division from the > previous remainder (102 monomials) with the primitive part of this > remainder is exact, this saves one pseudo-division. > I was looking at the source code yesterday and noticed that you figure out the likely degree of the gcd, but I couldn't figure out where it was actually used. But now I think I see where you are using it. > Looking how the content (188 monomials) is computed, it's done by exact > divisions only (it's the leading coefficient up to trivial coefficients). > Can you give me a hint where this is implemented. I didn't find this yesterday. It's a nice trick. Bill. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Multivariate polynomial factoring and bug(?)
Le vendredi 11 novembre 2016 07:03:46 UTC+1, Bill Hart a écrit : > > I assume you are using the modular algorithm to remove the final lot of > content at the end of the psr algorithm. Otherwise the algorithm takes > quite a long time, since even if we remove the known factors of the content > along the way, as specified by the algorithm, the result is far from > primitive, and so computing the content in the final step of the algorithm > takes a long time. > > Bill. > I'm using a trick for the last step of psrgcd: since the gcd should be of degree 6 wrt y (obtained by evaluation of other variables), when I have the remainder of degree 6 (1276 monomials), I check that the division from the previous remainder (102 monomials) with the primitive part of this remainder is exact, this saves one pseudo-division. Looking how the content (188 monomials) is computed, it's done by exact divisions only (it's the leading coefficient up to trivial coefficients). -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: sage 7.4 does not build on Ubuntu 16.10
Thanks for all helpful advice! I tried to patch, but still couldn't get past the error. Then I noticed a lovely Sage environment variable and voila! It's building! So all I did was: export SAGE_INSTALL_GCC=no make That's it! hopefully that will save somebody some time in the future! that is all pam oh yeah: installing on Ubuntu Gnome 16.10. my log was basically identical to the OP. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Error building sage devel: package: singular-4.0.3p4
Seems I posted too fast. Sorry for the spam. They error is due to a work around which I forgot to delete before building. Now it seems to work. (still building) On Friday, November 11, 2016 at 2:36:15 PM UTC+1, Simon Brandhorst wrote: > > See the log file. > > Best > > Simon > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Error building sage devel: package: singular-4.0.3p4
See the log file. Best Simon -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout. Found local metadata for singular-4.0.3p4 Attempting to download package singular-4.0.3p4.tar.bz2 from mirrors http://ftp.riken.jp/sagemath/spkg/upstream/singular/singular-4.0.3p4.tar.bz2 [..] singular-4.0.3p4 Setting up build directory for singular-4.0.3p4 Finished extraction Host system: Linux Quadrator 4.7.9-200.fc24.x86_64 #1 SMP Thu Oct 20 14:26:16 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux C compiler: gcc C compiler version: Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/6.2.1/lto-wrapper Target: x86_64-redhat-linux Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,objc,obj-c++,fortran,ada,go,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --disable-libgcj --with-isl --enable-libmpx --enable-gnu-indirect-function --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux Thread model: posix gcc version 6.2.1 20160916 (Red Hat 6.2.1-2) (GCC) patching file latest/factory/NTLconvert.cc (Stripping trailing CRs from patch; use --binary to disable.) patching file latest/configure Hunk #1 FAILED at 2328. 1 out of 1 hunk FAILED -- saving rejects to file latest/configure.rej Error applying '../patches/work_around_size_of_long_0.patch' real0m0.009s user0m0.005s sys 0m0.004s Error installing package singular-4.0.3p4 Please email sage-devel (http://groups.google.com/group/sage-devel) explaining the problem and including the relevant part of the log file /home/simon/sage/logs/pkgs/singular-4.0.3p4.log Describe your computer, operating system, etc. If you want to try to fix the problem yourself, *don't* just cd to /home/simon/sage/local/var/tmp/sage/build/singular-4.0.3p4 and type 'make' or whatever is appropriate. Instead, the following commands setup all environment variables correctly and load a subshell for you to debug the error: (cd '/home/simon/sage/local/var/tmp/sage/build/singular-4.0.3p4' && '/home/simon/sage/sage' --sh) When you are done debugging, you can type "exit" to leave the subshell.
