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Re: [GiNaC-list] products of exponentials
by Levi Boyles 08 Dec '11

08 Dec '11

Ok, thanks. > exp(a)*b*exp(c) -> exp(a+c)*b > > for any expression b. This one is not easy to do automatically within > GiNaC for various reasons, I think. > > I don't understand, why this would be hard? The product of 3 (or more) expressions is already represented as a sequence in the "mul" expression type, so couldn't ginac just find all subexpressions in the product of type exp, and then collect them? I guess I don't know how these auto-simplify methods are implemented. Anyway I will try the subs/wildcard method as you suggested, I didn't think of that. Thanks again! -Levi

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products of exponentials
by Levi Boyles 08 Dec '11

08 Dec '11

Hello, I'm dealing with products of large polynomial exponentials. However, whenever a product of two exponential terms appears they are not "simplified" into an exponential of a sum (unless the exponential args are numeric). Is there some way to coerce this to happen? Specifically I have a situation like this: exp(T-t_1)*exp(T-t_2) and I want something like this: exp(2T-t_1-t_2) or even exp(2T) exp(-t_1) exp(-t_2) I'm porting some of ginac's functionality to python (using cython), and I've been accessing ginac through that, so it's possible it's a bug on my side. However, I've tried to get the desired behavior in ginsh with no luck, so I'm guessing the default behavior is to not simplify products of exponentials. I've also tried creating a possymbol called "e" and simply raising it to the needed power, but this has the same behavior as the exp function. I've been using ginac1.6.1 Thanks, Levi

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Release 1.6.2
by Jens Vollinga 06 Nov '11

06 Nov '11

Hi everybody, GiNaC 1.6.6 is out and available. The changes are the following: * Fixed the parser to read GiNaC::lst again. * Fixed a compile warning (relevant to openSUSE build). * Fixed a bug concerning the subsitutions in indexed expressions (subs_options::no_index_renaming was ignored). As always, this release can be downloaded from http://www.ginac.de/Download.html Regards, Jens

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antisymmetric tensor with six indices
by Gilson Dallabona 29 Oct '11

29 Oct '11

Hello everyone, I'm trying to define a completely antisymmetric tensor with six indices, the Levi-Civita tensor in six dimensions, but without success. I followed the instructions of the manual but did not work. I tried the following: int main() { varidx xi_1(symbol("\\xi_1"),6), xi_2(symbol("\\xi_2"),6), xi_3(symbol("\\xi_3"),6), xi_4(symbol("\\xi_4"),6), xi_5(symbol("\\xi_5"),6), xi_6(symbol("\\xi_6"),6); symbol epsilon("varepsilon"); ex gamma_7 = indexed(epsilon, sy_anti(0,1,2,3).add(4).add(5), xi_1, xi_2, xi_3, xi_4, xi_5, xi_6) *dirac_gamma(xi_1.toggle_variance())*dirac_gamma(xi_2.toggle_variance()) *dirac_gamma(xi_3.toggle_variance())*dirac_gamma(xi_4.toggle_variance()) *dirac_gamma(xi_5.toggle_variance())*dirac_gamma(xi_6.toggle_variance()); return 0; } Anyone have any tips? Best regards, Gilson.

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Invitación a conectarnos en LinkedIn
by Jose Antonio Garcia Peiro 20 Sep '11

20 Sep '11

Me gustaría añadirte a mi red profesional en LinkedIn. -Jose Antonio Jose Antonio Garcia Peiro Estudiante de Universidad Miguel Hernández de Elche Murcia Area, Spain Confirm that you know Jose Antonio Garcia Peiro: https://www.linkedin.com/e/-qmwzwc-gssw3cr5-40/isd/4281101300/r-1XX1c3/?hs=… -- You are receiving Invitation to Connect emails. Click to unsubscribe: http://www.linkedin.com/e/-qmwzwc-gssw3cr5-40/kGy7Yg-6HHAoBPMg-Y4n5eWUQMwWs… (c) 2011 LinkedIn Corporation. 2029 Stierlin Ct, Mountain View, CA 94043, USA.

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how to drop terms in expression with small coefficients?
by Tomasz Rudny 07 Sep '11

07 Sep '11

Hi. I have the following problem - I have a polynomial P(x) and before I proceed with some calculations on it, I want to make sure it does not contain terms like for example: 10e-12 * x (in my case x is from (0, 1) so this is safe). I want to somehow get rid of such small terms. In another words for polynomial P(x) = 2.3 * x ^ 2 + 10e-12 * x + 3.76 I want to obtain polynomial Q(x) = 2.3 * x ^ 2 + 3.76 How do I do that i GiNaC? Please, help. I will kindly appreciate any advice. Kind Regards, Tomasz.

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re uindefined reference to cln
by Tamas Istvan 28 Aug '11

28 Aug '11

Hello, Attached the config.log file. Tamas

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attachment
by Tamas Istvan 26 Aug '11

26 Aug '11

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undefined reference to cln
by janos kovacs 25 Aug '11

25 Aug '11

Hello, When I make the GiNaC library, it gives the following error messages: Making all in ginsh make[1]: Entering directory `/home/ginac-1.6.1/ginsh' sed -n -f ./ginsh_fcn_help.sed <ginsh.1 >ginsh_fcn_help.h sed -n -f ./ginsh_op_help.sed <ginsh.1 >ginsh_op_help.h icpc -DHAVE_CONFIG_H -I. -I../config -I../ginac -I./../ginac -I../ginac -DIN_GINAC -O2 -xAVX -axAVX -parallel -vec-report -MT ginsh_parser.o -MD -MP -MF .deps/ginsh_parser.Tpo -c -o ginsh_parser.o ginsh_parser.cc mv -f .deps/ginsh_parser.Tpo .deps/ginsh_parser.Po icpc -DHAVE_CONFIG_H -I. -I../config -I../ginac -I./../ginac -I../ginac -DIN_GINAC -O2 -xAVX -axAVX -parallel -vec-report -MT ginsh_lexer.o -MD -MP -MF .deps/ginsh_lexer.Tpo -c -o ginsh_lexer.o ginsh_lexer.cc mv -f .deps/ginsh_lexer.Tpo .deps/ginsh_lexer.Po /bin/sh ../libtool --tag=CXX --mode=link icpc -O2 -xAVX -axAVX -parallel -vec-report -o ginsh ginsh_parser.o ginsh_lexer.o ../ginac/libginac.la-lreadline -lncurses libtool: link: icpc -O2 -xAVX -axAVX -parallel -vec-report -o .libs/ginsh ginsh_parser.o ginsh_lexer.o ..*/ginac/*.libs/libginac.so /usr/lib64/../lib64/libstdc++.so -lm -lreadline -lncurses -Wl,-rpath,/usr/lib64/../lib64 ginsh_parser.o: In function `f_fsolve(GiNaC::container<std::vector> const&)': ginsh_parser.cc:(.text+0x6224): undefined reference to `cln::cl_free_heap_object(cln::cl_heap*)' ginsh_parser.o: In function `f_integer_content(GiNaC::container<std::vector> const&)': ginsh_parser.cc:(.text+0x64d5): undefined reference to `cln::cl_free_heap_object(cln::cl_heap*)' ginsh_parser.o: In function `GiNaC::numeric::~numeric()': ginsh_parser.cc:(.gnu.linkonce.t._ZN5GiNaC7numericD1Ev[.gnu.linkonce.t._ZN5GiNaC7numericD1Ev]+0x1f): undefined reference to `cln::cl_free_heap_object(cln::cl_heap*)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::cl_I_to_L(cln::cl_I const&)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::print_complex(std::ostream&, cln::cl_print_flags const&, cln::cl_N const&)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::cosh(cln::cl_N const&)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::read_integer(std::istream&, cln::cl_read_flags const&)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::sqrt(cln::cl_N const&)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::equal(cln::cl_R const&, cln::cl_R const&)' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::cl_no_ring_init_helper::cl_no_ring_init_helper()' ..*/ginac/*.libs/libginac.so: undefined reference to `cln::ceiling1(cln::cl_R const&)' . . . ...and so on... Intel(R) C++ Intel(R) 64 Compiler XE for applications running on Intel(R) 64, Version 12.0.4.191 Build 20110427 Copyright (C) 1985-2011 Intel Corporation. Added compiler options: -O2 -xAVX -axAVX -parallel -vec-report Linux 64bit Kernel version 2.6.37.6 GiNaC version 1.6.1 cln version 1.3.2 CLN is installed to default path, e.g. /usr/local/lib and /usr/local/include Using gcc compiler, gives the same error. What can I do to correct this? Thank you in advance. Tamas Istvan

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Forge it !. WAS: Re: Weird: symbol * ddq_i, my_ex.subs((*ddq_i)==0) my_ex.subs(*ddq_i==0)my_ex.subs(symbol(*ddq_i)==0) ??
by Javier Ros 28 Jul '11

28 Jul '11

Sorry for disturbing, I solved the problem. For if some body is interested: I use a class symbol_numeric derived from symbol. the expression that was offending was conceptually of the type my_expression = symbol * (my_symbol_numeric) +my_symbol_numeric the result didn't simplified. I suppose this is CORRECT BEHAVIOR. My fault was the typecast removing it or changing it to symbol_numeric, solves the problem. That's why my_expression.subs(lst(symbol(my_symbol_numeric)==0,my_symbol_numeric ==0)) was needed. Now standard simplification my_expression.subs(my_symbol_numeric ==0) works. so I think the problem was related, although in a really involved manner, to the symbol factory known issue referred in GiNaC's Tutorial. Thank you again, Javier On Wed, Jul 27, 2011 at 11:09 PM, Javier Ros <jros(a)unavarra.es> wrote: > Jens, > > On Wed, Jul 27, 2011 at 8:41 PM, Jens Vollinga > <jens.vollinga(a)googlemail.com> wrote: >> Hi Javier, >> >> your information is a bit confusing. First you write: >> > I'm sorry. > >> On 27.07.2011 19:23, Javier Ros wrote: >>> >>> the following trivial simplifications >>> >>> my_ex.subs((*ddq_i)==0) >> >> ... >>> >>> go wrong no correct substitution, in different ways >> >> then you write: >> >>> Interestingly until now I was simplifying correctly using >>> >>> my_ex.subs((*ddq_i)==0) > > You can disregard this sentence. > >> So, once it goes wrong, then it goes well?!? Did you upgrade GiNaC to a >> newer version, maybe? > > Disregard the my_ex.subs((*ddq_i)==0) goes OK thing, > >> Anyway, could you, if possible, send a complete code example to explain your >> problem? It is hard to guess what the problem might be, otherwise. > > It's going to take some time to isolate, as I'm using a library that > I've build on top of GiNaC to generate the offending my, but I'll try > if I can reproduce it using plain GiNaC, writing and reading it back > in a plain > GiNaC program. > > In any case I suppose that the trivial simplifications > > my_ex.subs((*ddq_i)==0) > > my_ex.subs(*ddq_i==0) > > my_ex.subs(symbol(*ddq_i)==0) > > should coincident with these > > my_ex.subs(lst(symbol(*ddq_i)==0,*ddq_i==0)) > > my_ex.subs(lst(symbol(*ddq_i)==0,(*ddq_i)==0)) > > But unfortunately only the last two are working. > > Do you agree that this is not normal behavior?. > > Thank you, > > Javier >

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