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Question regarding symbolic differentiation
by Martin Ettl 22 Jul '12

22 Jul '12

Hello, i have a question regarding symbolic differentiation with GiNAC. Here is what i am trying to do: I have to variables a(t) and b(t), both are dependent from time (t). Suppose, this two variables are multiplied liked this: a(t) * b(t) Is it possible to derive this expression (a(t)*b(t)) according time with ginac. The only function i found in the manual is usefull for partial derivation, which does not help me here. Here is some example code: symbol a("a"), b("b"); // <-- how to tell ginac that variable a and b is dependant from variable t expression f = a*b; std::cout << f.diff(t,1) << std::endl; Many thanks in advance and best regards Martin Ettl

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linking error with ginac example program derivative.cpp
by Robert Durkacz 17 Jul '12

17 Jul '12

I am just starting with ginac but unable to build the derivative.cpp program from doc/examples/ in ginac-1.6.2 Others of the examples that I tried were built successfully, eg compile1.cpp and compile3.exe I am using these versions of ginac and cln: cln-1.3.2 ginac-1.6.2 These libraries were built without problems as per INSTALL instructions. compiler (gcc --version): gcc (GCC) 3.4.4 (cygming special, gdc 0.12, using dmd 0.125) platform (uname -a): CYGWIN_NT-5.1 dell 1.7.15(0.260/5/3) 2012-05-09 10:25 i686 Cygwin command line of compile and link steps: g++ -c -Wall -g -I.. -I../ginac -DIN_GINAC -o gcc/derivative.o derivative.cpp g++ -o derivative gcc/derivative.o ../ginac/.libs/libginac.a /usr/local/lib/libcln.a -ldl ../ginac/.libs/libginac.a(parser.o): In function `_ZNSt16invalid_argumentD1Ev': /home/Owner/technical/ginac-1.6.2/ginac/parser/parser.h:46: multiple definition of `GiNaC::container<std::list>::info(unsigned int) const' ../ginac/.libs/libginac.a(lst.o):/usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/list.tcc:(.text+0x0): first defined here collect2: ld returned 1 exit status It is beyond my current abilities to sort out this problem. Could someone tell me what is going wrong?

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internal representation of expressions
by Felipe Bordeu 18 Apr '12

18 Apr '12

Hello, I'm trying to debug a program, and the problems is that the terms in a sum are not ordered in the same way in every run. for example : 1 run : A+B+C gives A+B+C 2 run : A+B+C gives C+B+A ... I know that the 2 expressions are equal but I will like GiNaC to represent the expression always in the same way. It's only for debugging so I don't care about performance. Thanks Felipe -- Felipe Bordeu Weldt Ingénieur de Recherche ------------------------------------- Tél. : 33 (0)2 40 37 16 57 Fax. : 33 (0)2 40 74 74 06 Felipe.Bordeu(a)ec-nantes.fr Institut GeM - UMR CNRS 6183 École Centrale Nantes 1 Rue de La Noë, 44321 Nantes, FRANCE -------------------------------------

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Using clang to build libraries - ginac and cln
by Fletcher, John P 07 Apr '12

07 Apr '12

I sent this to the Clang list, and am sending it here too as I see that GiNaC has been built with Clang. I want to build GiNaC with Clang 31 (SVN) and libc++ to work with code running under -std=c++0x Please let me know if there is somewhere where the makefile is described. Thanks John ________________________________________ From: Fletcher, John P Sent: 07 April 2012 00:11 To: cfe-dev(a)cs.uiuc.edu Subject: Using clang to build libraries - ginac and cln Hi I need to rebuild the libraries ginac and cln to work with clang31 libc++ and C++11. Is there a tutorial anywhere on how to build the makefile to do this? Thanks John

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Number representation
by Michel Dupront 29 Mar '12

29 Mar '12

Hello, I am new to ginac. At the moment I am playing with the tool trying to compute finite element bases as in SyFi. As a solution of a system of linear equations I got: {b0_0==0.25,b0_1==-0.25,b0_2==-0.25,b0_3==0.25} But I would have wanted the fraction 1/4 instead of 0.25. How can I force ginac to not compute fractions ? Thank in advance.

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converting expressions to double
by Tomasz I. Rudny 02 Mar '12

02 Mar '12

Hello, Thank you for GiNaC and your support - I have almost completed my PhD with it :) But I have a little problem still... I have a symbolic expression F(x, y, z, u) and I need to 1) substitute x, y, z, u with values (given as double), 2) calculate F, 3) export F as double. My code looks like this: double my_method(GiNaC::ex & ex, double x1, double y1, double z1, double u1) { numeric _x(x1), _y(y1), _z(z1), _u(u1); ex = ex.subs(lst(x == _x, y == _y, z == _z, u == _u)); ex = ex.evalf(); numeric tmp = ex_to<numeric>(ex); return tmp.to_double(); } Unfortunately, the last instruction (to_double() ) fails and throws the exception: terminate called after throwing an instance of 'cln::notreached_exception' what(): Internal error: statement in file real/conv/cl_R_to_double.cc, line 55 has been reached!! Please send the authors of the program a description how you produced this error! I read the response cited below, but still I can't fix it. Could you please help me? Thank you very much, Tomasz. Warsaw University of Technology ========================= Hi! On 11/02/2010 08:12 AM, Sebastian Luther wrote: > below you'll find a small test program that crashes for me. > > -------------------------------------------- > #include<ginac/ginac.h> > #include<iostream> > > int main(int argc, char* argv[]) > { > GiNaC::parser p; > GiNaC::ex e = p("941480149401/1250000000000000*2^(5/91)"); > GiNaC::numeric n = GiNaC::ex_to<GiNaC::numeric>(e); > double x = n.to_double(); //throws the exception below > return 0; > } Since e is a product (of a rational number and a power of two) it must be converted to a number using evalf() before trying to assign it to a simple numeric object. > Looks like the real problem lays in cln, but I'm not sure how to reproduce it there. It has nothing to do with CLN. Best wishes -richy. -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>

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How to convert epsilon_tensor in a matrix?
by Marco André Ferreira Dias 26 Feb '12

26 Feb '12

Hi, I have a very naive question: my program compute some dirac_traces, and some epsilon_tensors arises in this process. I have to convert the tensorial structure to matricial to compute it numerically, but until now I don't figure out how to manipulate expressions like this ============= [[31],[0.0],[0.0],[-31]]~sigma*[[6.3],[0.0],[0.0],[6.30]]~alpha*[[19.33],[-1.108],[-5.4],[18.6]].gamma*eps.delta.sigma~gamma.alpha*[[16.781197650788506337],[4.96],[11.38],[11.2]]~gamma ============= Note that the episilon tensor is fully contracted by four (4x1) vectors. I will be glad for any suggestion given! Regards, Marco

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Simplifying a hierarchy of rational powers on positive symbols
by DerManu＠WorksLikeClockwork.com 21 Feb '12

21 Feb '12

Hi GiNaC Gurus, Consider the following expression: (2^(2/3)*x^2)^(3/2) where x is positive. I'd expect eval() to reduce this to 2*x^3, but it happens only, when calling evalf(). However, I'd like other possible parts of the expression to stay exact, so evalf() isn't an option. Here's the code for the above expression: possymbol x("x"); ex e = power( power(2,numeric(2)/numeric(3)) * power(x, 2) , numeric(3)/numeric(2) ); std::cout << e.eval() << " " << e.evalf() << std::endl; // I know eval is redundant, but it adds a dramatic element ;) Note this situation is somewhat related yet much simpler than Topic [1] because we're dealing with purely numeric powers here. Still it seems, this kind of simplification is just not wanted. Is that correct? Or is there a trick to make it all work easily? Would it be a sensible approach to write a map_function functor that grabs all powers that have positive muls as base and apply the power to all mul ops individually? Best regards, Emanuel [1] http://www.ginac.de/pipermail/ginac-list/2011-December/001862.html

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Problem with parser after updating from 1.6.1 to 1.6.2
by Jafar Akhundov 24 Jan '12

24 Jan '12

Hello everyone! After updating from GiNaC v.1.6.1 to v.1.6.2 the following code (which is actually taken from the tutorial) won't compile anymore. { symbol x, y; symtab table; table["x"] = x; table["y"] = y; parser reader(table); ex e = reader("2*x+sin(y)"); } This is what I get : ginac1.cc:(.text+0x36c): undefined reference to `GiNaC::parser::parser(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, GiNaC::ex, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, GiNaC::ex> > > const&, bool, std::map<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, unsigned int>, GiNaC::ex (*)(std::vector<GiNaC::ex, std::allocator<GiNaC::ex> > const&), GiNaC::PrototypeLess, std::allocator<std::pair<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, unsigned int> const, GiNaC::ex (*)(std::vector<GiNaC::ex, std::allocator<GiNaC::ex> > const&)> > > const&)' Anyone help or having similar issues? Thanks! -- Jafar

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libreadline and dlopen() issues
by Luke 10 Jan '12

10 Jan '12

I'm trying to build ginac from source (master branch, commit a104ecb34a015fc40a4bdc16ae6ea038ecb8c55d). The configure step is unable to find libreadline for some reason and I can't figure out why. Here is what I've got: luke@ThinkPad-W510:~/repos/ginac(master)$ ll /usr/lib/libreadline*.* -rw-r--r-- 1 root root 505980 2011-09-01 10:43 /usr/lib/libreadline.a lrwxrwxrwx 1 root root 21 2011-09-01 10:43 /usr/lib/libreadline.so -> /lib/libreadline.so.6 luke@ThinkPad-W510:~/repos/ginac(master)$ ls /usr/include/readline/ chardefs.h history.h keymaps.h readline.h rlconf.h rlstdc.h rltypedefs.h tilde.h luke@ThinkPad-W510:~/repos/ginac(master)$ ./configure checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for a thread-safe mkdir -p... /bin/mkdir -p checking for gawk... gawk checking whether make sets $(MAKE)... yes checking for g++... g++ checking whether the C++ compiler works... yes checking for C++ compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking for style of include used by make... GNU checking dependency style of g++... gcc3 checking how to run the C++ preprocessor... g++ -E checking build system type... x86_64-unknown-linux-gnu checking host system type... x86_64-unknown-linux-gnu checking how to print strings... printf checking for gcc... gcc checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking dependency style of gcc... gcc3 checking for a sed that does not truncate output... /bin/sed checking for grep that handles long lines and -e... /bin/grep checking for egrep... /bin/grep -E checking for fgrep... /bin/grep -F checking for ld used by gcc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B checking the name lister (/usr/bin/nm -B) interface... BSD nm checking whether ln -s works... yes checking the maximum length of command line arguments... 1572864 checking whether the shell understands some XSI constructs... yes checking whether the shell understands "+="... yes checking how to convert x86_64-unknown-linux-gnu file names to x86_64-unknown-linux-gnu format... func_convert_file_noop checking how to convert x86_64-unknown-linux-gnu file names to toolchain format... func_convert_file_noop checking for /usr/bin/ld option to reload object files... -r checking for objdump... objdump checking how to recognize dependent libraries... pass_all checking for dlltool... no checking how to associate runtime and link libraries... printf %s\n checking for ar... ar checking for archiver @FILE support... @ checking for strip... strip checking for ranlib... ranlib checking command to parse /usr/bin/nm -B output from gcc object... ok checking for sysroot... no checking for mt... mt checking if mt is a manifest tool... no checking how to run the C preprocessor... gcc -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking for dlfcn.h... yes checking for objdir... .libs checking if gcc supports -fno-rtti -fno-exceptions... no checking for gcc option to produce PIC... -fPIC -DPIC checking if gcc PIC flag -fPIC -DPIC works... yes checking if gcc static flag -static works... yes checking if gcc supports -c -o file.o... yes checking if gcc supports -c -o file.o... (cached) yes checking whether the gcc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... yes checking whether to build shared libraries... yes checking whether to build static libraries... yes checking how to run the C++ preprocessor... g++ -E checking for ld used by g++... /usr/bin/ld -m elf_x86_64 checking if the linker (/usr/bin/ld -m elf_x86_64) is GNU ld... yes checking whether the g++ linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking for g++ option to produce PIC... -fPIC -DPIC checking if g++ PIC flag -fPIC -DPIC works... yes checking if g++ static flag -static works... yes checking if g++ supports -c -o file.o... yes checking if g++ supports -c -o file.o... (cached) yes checking whether the g++ linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking dynamic linker characteristics... (cached) GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking for flex... flex checking lex output file root... lex.yy checking lex library... -lfl checking whether yytext is a pointer... yes checking for bison... bison -y checking for bison... /usr/bin/bison checking for standard C++ header files... yes checking for pkg-config... /usr/bin/pkg-config checking pkg-config is at least version 0.9.0... yes checking for CLN... yes checking for ld used by GCC... /usr/bin/ld -m elf_x86_64 checking if the linker (/usr/bin/ld -m elf_x86_64) is GNU ld... yes checking for shared library run path origin... done checking for long long... yes checking for unistd.h... (cached) yes checking whether struct rusage is declared in <sys/resource.h>... yes checking for tgetent... no checking for tgetent in -lncurses... no checking for tgetent in -ltermcap... no checking readline/readline.h usability... yes checking readline/readline.h presence... yes checking for readline/readline.h... yes checking readline/history.h usability... yes checking readline/history.h presence... yes checking for readline/history.h... yes checking for version of libreadline... yes checking for readline in -lreadline... no checking for dlfcn.h... (cached) yes checking for dlopen in -ldl... no checking for dlopen... no configure: WARNING: Could not found working dlopen(). GiNaC::compile_ex will be disabled. checking for doxygen... /home/luke/usr/bin/doxygen checking for latex... /home/luke/usr/texlive/2011/bin/x86_64-linux/latex checking for pdflatex... /home/luke/usr/texlive/2011/bin/x86_64-linux/pdflatex checking for makeindex... /home/luke/usr/texlive/2011/bin/x86_64-linux/makeindex checking for makeinfo... /usr/bin/makeinfo checking for dvips... /home/luke/usr/texlive/2011/bin/x86_64-linux/dvips checking for fig2dev... /usr/bin/fig2dev configure: creating ./config.status config.status: creating Makefile config.status: creating GiNaC.spec config.status: creating ginac.pc config.status: creating ginac/Makefile config.status: creating check/Makefile config.status: creating ginsh/Makefile config.status: creating ginsh/ginsh.1 config.status: creating tools/Makefile config.status: creating tools/viewgar.1 config.status: creating tools/ginac-excompiler config.status: creating doc/Makefile config.status: creating doc/examples/Makefile config.status: creating doc/tutorial/Makefile config.status: creating doc/reference/Makefile config.status: creating doc/reference/DoxyfileHTML config.status: creating doc/reference/DoxyfileTEX config.status: creating doc/reference/DoxyfilePDF config.status: creating doc/reference/Doxyfooter config.status: creating config/config.h config.status: config/config.h is unchanged config.status: creating ginac/version.h config.status: ginac/version.h is unchanged config.status: executing depfiles commands config.status: executing libtool commands === The following minor problems have been detected by configure. === Please check the messages below before running "make". === (see the section 'Common Problems' in the INSTALL file) == ginsh will not compile, because libreadline could not be found. Configuration of GiNaC 1.6.2 done. Now type "make". Any ideas why configure wouldn't be finding readline or how to go about solving this problem? Also, I don't understand why a working dlopen() was not found. I have /usr/include/dlfcn.h, and I have successfully compiled code that makes calls to dlopen() and friends. Thanks, ~Luke -- "Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety." -- Benjamin Franklin, Historical Review of Pennsylvania, 1759

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