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question about lorentz_g contract with sy_anti tensor
by Feng Feng 23 May '19

23 May '19

Hi all, I wonder is there a way or method to simplify the expression with a sy_anti tensor contracted with a lorent_g to 0? Please have a look at the following code, I expect ret is 0, and the output looks like “A~b~a.c~c”, it is actually 0 due to the sy_anti, but I wonder, is there a way or a method to simplify those expression directly to 0? Thanks very much! using namespace GiNaC; using namespace std; int main(int argc, char** argv) { symbol a("a"), b("b"), c("c"), d("d"), A("A"); symbol D("D"); varidx ia(a,D), ib(b,D), ic(c,D), id(d,D); auto ret = indexed(A, sy_anti(0,1,2,3), ia,ib,ic,id) * lorentz_g(ic.toggle_variance(), id.toggle_variance()); cout << simplify_indexed(ret) << endl; return 0; } Best regards! Feng

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Crash with zeta({7, 3}), and performance difference with G(...)
by Vitaly Magerya 22 May '19

22 May '19

Hi, folks. I've run into a crash; here it is: (gdb) run Starting program: .../ginac/build/ginsh/ginsh ginsh - GiNaC Interactive Shell (GiNaC V1.7.6) __, _______ Copyright (C) 1999-2019 Johannes Gutenberg University Mainz, (__) * | Germany. This is free software with ABSOLUTELY NO WARRANTY. ._) i N a C | You are welcome to redistribute it under certain conditions. <-------------' For details type `warranty;'. Type ?? for a list of help topics. > evalf(zeta({7,3})); 0.008419668503096332361 > Digits=2000; 2000 > evalf(zeta({7,3})); Program received signal SIGSEGV, Segmentation fault. 0x00007ffff786c3ca in cln::operator*(cln::cl_N const&, cln::cl_N const&) () from /usr/lib/libcln.so.6 (gdb) bt #0 0x00007ffff786c3ca in cln::operator*(cln::cl_N const&, cln::cl_N const&) () from /usr/lib/libcln.so.6 #1 0x00005555556402c1 in GiNaC::(anonymous namespace)::crandall_Y_loop(cln::cl_N const&, std::vector<cln::cl_N, std::allocator<cln::cl_N> > const&) () #2 0x0000555555658ab9 in GiNaC::zeta1_evalf(GiNaC::ex const&) () #3 0x00005555555f5697 in GiNaC::function::evalf() const () #4 0x0000555555586023 in f_evalf(GiNaC::container<std::vector> const&) () #5 0x000055555558d7c7 in yyparse() () #6 0x0000555555577087 in main () (gdb) Interestingly evaluating the same zeta with G works fine: > Digits=2000; 2000 > evalf(G({0,0,0,0,0,0,1,0,0,1},1)); 0.00841966850309633242396857971467065063691... Also with Digits=500, evaluating zeta({7,3}) takes ~10 seconds, while it's only 0.6 seconds for G({0,0,0,0,0,0,1,0,0,1},1). Anyone has ideas as to why is there such difference in performance, and is there an even faster way?

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casting
by Pedro Sosa 07 May '19

07 May '19

Hello, I'm a begginer and I don't find how to convert from ex to double in the tutorialSomebody can help me? Thanks

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Different Compiling Command
by Hanni Puspita 01 May '19

01 May '19

Hello, I am new to GiNaC and I follow a pdf doc tutorial that documents GiNaC 1.7.6 for installation and testing. However there is a inconsistency that I found in the pdf doc on how to compile the scripts. Not working : G++ HELLO.CPP -O HELLO -LCLN -LGINAC Works : G++ HELLO.CPP -O HELLO -LGINAC -LCLN Perhaps you should update the tutorial docs? I use Windows 10 and GCC 7.4.0. Thanks. Best regards, Hanni Puspita

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Re: [GiNaC-list] Problem about series
by Feng Feng 23 Apr '19

23 Apr '19

Thanks very much for the quick fix, thanks again! > Feng Feng, > > On 13.04.19 07:06, Feng Feng wrote: > > I am sorry for that I didn't make it clear. > > > > the test program shows that s1 output is Order(ep^(-1)), > > there is no other term in the output, so s1 output indicates > > that there is no ep^(-2) in expr, I am not sure I interpret the > > s1 output correctly or not? > > I'm sure you interpret it correctly. There is indeed a bug in GiNaC. > > A reduced example of the same problem is this: > > symbol x("x"), ep("?"); > ex expr = x * (tgamma(ep) / ep - sin(ep) / ep); > > cout << expr.series(ep, -2) << endl; > // good: Order(?^(-2)) > > cout << expr.series(ep, -1) << endl; > // D'oh: Order(?^(-1)) > > cout << expr.series(ep, 0) << endl; > // good: (x)*?^(-2)+(-Euler*x)*?^(-1)+Order(1) > > It seems it was broken by commit db81420a61 in 2004. > > Best, > -richy. > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > GiNaC-list mailing list > GiNaC-list(a)ginac.de > https://www.cebix.net/mailman/listinfo/ginac-list > > > ------------------------------ > > End of GiNaC-list Digest, Vol 140, Issue 8 > ******************************************

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Release 1.7.6
by Richard B. Kreckel 22 Apr '19

22 Apr '19

Hi, A new GiNaC version has just been released. The changes are: * Fix a bug in mul::series() about asymptotic order term. * Fix cl_N code generation for small negative integers. * Fix multiple polylog computation related to trailing zeros and user-specified signs for small imaginary parts. * Fix CMake build with Python3. Happy Easter! -richy.

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how to convert CLN __float128 and long double?
by Feng Feng 22 Apr '19

22 Apr '19

Hi, I wonder if there is a way to convert the cl_N or GiNaC numeric type to c++ __float128 or long double? since the both also appear in CUBA. Thanks very much! Best regards! Feng

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Re: [GiNaC-list] Problem about series
by Feng Feng 21 Apr '19

21 Apr '19

I am sorry for that I didn't make it clear. the test program shows that s1 output is Order(ep^(-1)), there is no other term in the output, so s1 output indicates that there is no ep^(-2) in expr, I am not sure I interpret the s1 output correctly or not? PS: from s2 output indicates that there is an ep^(-2) term in expr. Thanks very much! Best Regards! Feng > -----原始邮件----- > 发件人: ginac-list-request(a)ginac.de > 发送时间: 2019-04-12 18:00:03 (星期五) > 收件人: ginac-list(a)ginac.de > 抄送: > 主题: GiNaC-list Digest, Vol 140, Issue 5 > > Send GiNaC-list mailing list submissions to > ginac-list(a)ginac.de > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.cebix.net/mailman/listinfo/ginac-list > or, via email, send a message with subject or body 'help' to > ginac-list-request(a)ginac.de > > You can reach the person managing the list at > ginac-list-owner(a)ginac.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of GiNaC-list digest..." > > > Today's Topics: > > 1. Re: Problem about series (Richard B. Kreckel) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 11 Apr 2019 23:29:23 +0200 > From: "Richard B. Kreckel" <kreckel(a)in.terlu.de> > To: ginac-list(a)ginac.de > Subject: Re: [GiNaC-list] Problem about series > Message-ID: <920c06c9-7a44-f2eb-43d3-2b46adbae6e6(a)in.terlu.de> > Content-Type: text/plain; charset=utf-8 > > Feng Feng, > > Sorry, I don't see what's wrong with this. > > On 08.04.19 01:00, Feng Feng wrote: > > Hi, I got a problem ?about the series function, > > I used the following test code(see below or the attached file), > > the s1 output only gives Order(ep^(-1)), while s2 output indicates that > > there is a 1/ep^2 term, so the s1 is not correct or I used the series in > > a wrong way? > > > > Thanks a lot! > > > > #include <ginac/ginac.h> > > > > using namespace GiNaC; > > using namespace std; > > > > int main(int argn, char** args) { > > ? ? symbol x1("x1"),x2("x2"),x3("x3"),x4("x4"); > > ? ? symbol ep("ep"); > > ? ? ex expr = -2*pow(x1,-1 + ep)*(exp(3*ep*Euler)*pow(ep,-1)*pow(x2,-3*ep)* > > ? ? ? pow(1 + x3 + x4 + x3*x4,-3*ep)* > > ? ? ? pow(1 + x2 + x3 + x2*x3 + x4 + x2*x4 + x3*x4 + x2*x3*x4,-2 + 4*ep)*tgamma(3*ep) - > > ? ? ?exp(3*ep*Euler)*pow(ep,-1)*pow(x2,-3*ep)*pow(1 + x3 + x4 + x3*x4,-3*ep)* > > ? ? ? pow(1 + x2 + x3 + x1*x3 + x2*x3 + x4 + x2*x4 + x3*x4 + x1*x3*x4 + x2*x3*x4, > > ? ? ? ?-2 + 4*ep)*tgamma(3*ep)); > > ? ?? > > ? ? auto s1 = expr.series(ep,-1); > > ? ? cout << s1.normal() << endl; > > ? ?? > > ? ? auto s2 = expr.series(ep,0); > > ? ? cout << s2.normal() << endl; > > ? ?? > > ? ? return 0; > > } > > You did notice that this Laurent series is expanded in ep, not in ep^-1, > right? > > It might help if you reduce your example program to the bare minimum. > Then, if you still think it's wrong, please explain what exactly you > expected instead of the output you got and why. > > All my best, > -richy. > -- > Richard B. Kreckel > <https://in.terlu.de/~kreckel/> > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > GiNaC-list mailing list > GiNaC-list(a)ginac.de > https://www.cebix.net/mailman/listinfo/ginac-list > > > ------------------------------ > > End of GiNaC-list Digest, Vol 140, Issue 5 > ******************************************

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Problem about series
by Feng Feng 11 Apr '19

11 Apr '19

Hi, I got a problem about the series function, I used the following test code(see below or the attached file), the s1 output only gives Order(ep^(-1)), while s2 output indicates that there is a 1/ep^2 term, so the s1 is not correct or I used the series in a wrong way? Thanks a lot! #include <ginac/ginac.h> using namespace GiNaC; using namespace std; int main(int argn, char** args) { symbol x1("x1"),x2("x2"),x3("x3"),x4("x4"); symbol ep("ep"); ex expr = -2*pow(x1,-1 + ep)*(exp(3*ep*Euler)*pow(ep,-1)*pow(x2,-3*ep)* pow(1 + x3 + x4 + x3*x4,-3*ep)* pow(1 + x2 + x3 + x2*x3 + x4 + x2*x4 + x3*x4 + x2*x3*x4,-2 + 4*ep)*tgamma(3*ep) - exp(3*ep*Euler)*pow(ep,-1)*pow(x2,-3*ep)*pow(1 + x3 + x4 + x3*x4,-3*ep)* pow(1 + x2 + x3 + x1*x3 + x2*x3 + x4 + x2*x4 + x3*x4 + x1*x3*x4 + x2*x3*x4, -2 + 4*ep)*tgamma(3*ep)); auto s1 = expr.series(ep,-1); cout << s1.normal() << endl; auto s2 = expr.series(ep,0); cout << s2.normal() << endl; return 0; }

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Re: [GiNaC-list] GiNaC-list Digest, Vol 140, Issue 3
by Feng Feng 08 Apr '19

08 Apr '19

Thanks so much for the fix! > -----原始邮件----- > 发件人: ginac-list-request(a)ginac.de > 发送时间: 2019-04-05 18:00:01 (星期五) > 收件人: ginac-list(a)ginac.de > 抄送: > 主题: GiNaC-list Digest, Vol 140, Issue 3 > > Send GiNaC-list mailing list submissions to > ginac-list(a)ginac.de > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.cebix.net/mailman/listinfo/ginac-list > or, via email, send a message with subject or body 'help' to > ginac-list-request(a)ginac.de > > You can reach the person managing the list at > ginac-list-owner(a)ginac.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of GiNaC-list digest..." > > > Today's Topics: > > 1. Re: problem about cl_N output format (Richard B. Kreckel) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 4 Apr 2019 20:29:28 +0200 > From: "Richard B. Kreckel" <kreckel(a)in.terlu.de> > To: ginac-list(a)ginac.de > Subject: Re: [GiNaC-list] problem about cl_N output format > Message-ID: <127d10ab-b138-06b7-950e-a104ca251e4e(a)in.terlu.de> > Content-Type: text/plain; charset=utf-8 > > Hi, > > On 04.04.19 08:05, Feng Feng wrote: > > Hi all, I got a problem with the csrc_cl_N output format, for example, > > > > ex expr = pow(1+x(0),-6); > > > > expr.print(print_csrc_cl_N(cout)); > > > > > > I got an output as > > > > > > expt( x(0)+1, (--6)) > > > > > > and it seems that "--" should be only one "-". > > > > so is it normal or a bug? > > Clearly a bug. I've pushed a fix to git. > > Thanks for reporting this! > > -richy. > > PS: In the future, when reporting bugs in GiNaC or in other open source > projects, please send in complete test programs. This makes it easier > for developers. > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > GiNaC-list mailing list > GiNaC-list(a)ginac.de > https://www.cebix.net/mailman/listinfo/ginac-list > > > ------------------------------ > > End of GiNaC-list Digest, Vol 140, Issue 3 > ******************************************

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