September 2007 - GiNaC-list

new tinfo method makes is_a less efficient
by Diego Conti 13 Sep '07

13 Sep '07

Hi, I'm a mathematician and I find GiNaC very useful for doing calculations. Unfortunately, the new tinfo mechanism in version 1.4.0 breaks my code, and I am not sure how to fix that. Basically, what I need is an efficient version of is_a (actually, is_a<ncmul>) that does not rely on dynamic_cast. With the old tinfo method, I could simply redefine: template<> inline bool is_a<ncmul>(const basic & obj) { return (obj.tinfo()&TINFO_MASK)==TINFO_ncmul; } where TINFO_MASK is the constant 0x001fffffU, and the classes I derived from ncmul had appropriate tinfo constants. With the new method, where the tinfo_key is a pointer, the above code does not work. One obvious alternative is the following: struct tinfo_static_t <http://www.ginac.de/reference/structGiNaC_1_1tinfo__static__t.html> { const tinfo_static_t* derives_from; //NULL if derived from void, otherwise points to tinfo_static member in superclass <http://www.ginac.de/reference/structGiNaC_1_1tinfo__static__t.html> }; typedef const tinfo_static_t * tinfo_t; and then template <class T> inline bool is_a(const basic &obj) { const tinfo_static_t* tinfo=obj.tinfo(); do { if (tinfo==&T::tinfo_static) return true; tinfo = tinfo->derives_from <http://www.ginac.de/reference/structGiNaC_1_1tinfo__static__t.html>; } while (tinfo!=NULL); return false; } This appears reasonably efficient, but it will not work because, for instance, add::return_type_tinfo <http://www.ginac.de/reference/classGiNaC_1_1add.html#b2>() can return this, which can be converted to a pointer to void but not to a pointer to tinfo_static_t. I really do not understand the meaning of this choice. Can someone explain? What would I need to change in order to make the above code work? Thanks in advance Diego Conti

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Installation ginac(1.4) + cln(1.1.13) on powermac
by Hans-Jürgen Greif 11 Sep '07

11 Sep '07

Hi to all, because octave can't install symbolic package, I have tried to install ginac on powermac G4 v. 10.4.10. The ginac configure script ends with: checking for pkg-config... /sw/bin/pkg-config checking pkg-config is at least version 0.9.0... yes checking for CLN... configure: error: Package requirements (cln >= 1.1.6) were not met. Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. Alternatively you may set the CLN_CFLAGS and CLN_LIBS environment variables to avoid the need to call pkg-config. See the pkg-config man page for more details. ________________________ I have no experience with pkg-config, so I decided to use environments variables bash shell: declare -x CLN_CFLAGS="-I/usr/local/include/cln" declare -x CLN_ LIBS="-L/usr/local/libs/ -lcln" for installed cln 1.1.13 which is definitely greater (newer) as 1.1.6. However, this does not work. Can anyone tell to me, how to set the variables above. Or can anyone give a pkg file to handle this problem? Sincerely, Hans-Jürgen Greif

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Installation ginac(1.4) +cln(1.1.3) on powermac
by Hans-Jürgen Greif 08 Sep '07

08 Sep '07

The system I use is (uname -a) Darwin alpha.local 8.10.0 Darwin Kernel Version 8.10.0: Wed May 23 16:50:59 PDT 2007; root:xnu-792.21.3~1/RELEASE_PPC Power Macintosh powerpc The config.log is attached. Regards, Hans-Jürgen Greif

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