- GiNaC-list - ginac.de

Maps and sets of symbols?
by John Pye 14 Sep '05

14 Sep '05

Hi again, I've got an application I'm working on which needs the ability to handle STL maps and sets containing symbols. In order to be able to use these classes, I have to define an ordering (a less-than operator) for symbols. At the moment I use the 'get_name' method and then compare symbol names as strings, but this isn't really ideal, since it takes a a lot of processing, plus GiNaC is quite happy to tolerate more than one symbol with the same name, so my map/set should be as well. I notice that GiNaC's symbol class has a 'serial number' as one of its properties. Is there any way I can access that value via a public method? Or is there another method suggested for creating sets and maps of symbols? //// Ordering for symbols based on name (there should be a better way)/ *class* symbol_lt{ *public*: bool *operator*()(const GiNaC::symbol &a, const GiNaC::symbol &b) const; }; Cheers JP

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Getting a pointer to an element in a list?
by John Pye 10 Sep '05

10 Sep '05

Hi all A hopefully pretty simple question about lists in GiNaC. I have a little fragment of code like this: class SymbolicSystem{ private: GiNaC::lst F; public: const ex * getExpressionPtr(const unsigned &i) const{ *return* &(F[i]); } } Is there something about the implementation of the operator[] in GiNaC::list that stops me from being able to do this? GCC gives me a warning, like this: warning: taking address of temporary This might be an elementary C++ mistake, but just in case, I thought I'd ask. Cheers JP

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Symbolic functions with multiple outputs
by John Pye 08 Sep '05

08 Sep '05

Hi again Just reading the GiNaC 1.3.1 manual, in the section about adding new symbolic functions, section 6.2 Is it possible to create symbolic functions that have multiple, matrix, or list outputs? Is there a way to assign the outputs of a multiple-valued symbolic function to elements of a list? lst(a,b,c) = three_valued_function(d,e); For example, a case where one might want to do this sort of thing would be evaluation of fluid properties, like so lst(p,h) = pressure_and_enthalpy_of_water(T, rho); When finally evaluating this numerically, eg once T and rho are known, having this as one symbolic function allows some intrinsic optimisation of calls to the thermodynamic property calculation routines. Thanks for your help, and sorry for the stream of silly questions... Cheers JP -- John Pye School of Mechanical and Manufacturing Engineering The University of New South Wales Sydney NSW 2052 Australia t +61 2 9385 5127 f +61 2 9663 1222 mailto:john.pye_AT_student_DOT_unsw.edu.au http://pye.dyndns.org/

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Referencing array of symbols?
by John Pye 07 Sep '05

07 Sep '05

Hi there I'm struggling to understand how to correctly use the 'idx' functionality in GiNaC. If anyway would be able to offer some suggestions or relevant examples, I'd be very appreciative. My application is for something like a simple one-dimensional pipe flow calculation. For example, I would like to evaluate the pressures in the flow alow a pipe. I will set up some expressions relating the values of my pressures at different nodes in my pipe, then I will substitute values for those pressures and then evaluate residuals from my expressions. So I am hoping to write something like sym p[100] = sym[]("p"); sym mdot[100] = sym[]("mdot"); sym rho("rho"); lst f; for(int i=1; i<100; ++i){ f.append( p[i] - p[i-1] - 0.5 * rho * pow( mdot[i-1] / (rho * A) , 2) ); } for(int i=1; i<100; ++i){ f.subs(p[i] == 1.5454223494); } cerr << f << endl; In this way, I will have an array of symbols and a lst of expressions. I can then use those to generate equations which can be exported to s numerical solver. Perhaps the best way to do this is to create standard C-style array of symbols? I am hoping there's a more elegant way. Also, I'd like to know your thoughts on how efficient this sort of approach might be as the number of equations / symbols grows. Am I right in thinking I shuold be using the 'idx' class? Cheers JP -- John Pye School of Mechanical and Manufacturing Engineering The University of New South Wales Sydney NSW 2052 Australia t +61 2 9385 5127 f +61 2 9663 1222 mailto:john.pye_AT_student_DOT_unsw.edu.au http://pye.dyndns.org/

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GiNaC inside ROOT?
by John Pye 02 Sep '05

02 Sep '05

Hi all Since ginsh is built on top of CINT, it seemed reasonable to hope that GiNaC might able to be run from insite ROOT -- has anybody been able to do this? ROOT is here: http://root.cern.ch/ With the following simple test program, > #include <iostream> > #include <ginac/ginac.h> > > using namespace std; > using namespace GiNaC; > > int main(){ > symbol x("x"); > > ex y = pow(x+1,3); > > ex dydx = y.diff(x); > > cerr << dydx; > } I get an error message from ROOT > Processing roottest.C... > Limitation: Reference member not supported. Please use pointer > FILE:/usr/include/ginac/print.h LINE:101 So maybe I can't use GiNaC inside ROOT? This is with GiNaC 1.3.2. Would appreciate any suggestions. How does gTybalt get around this? Cheers JP

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Problem in adding functions
by Nikhil Bansal 30 Aug '05

30 Aug '05

Hi, I was trying to add some functions (e.g. binary xor) to the Ginac expressions as it is done for functions like cos. The library is accepting those functions standalone but not using them with any coefficients. e.g. it is giving me expressions like XOR(e1, e2) but not like c*XOR(e1, e2) where c is a constant. Could someone point me to the place in library where it scales the functions by multiplying with some constants. Thanks, Nikhil

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Strange behaviour in symbol declaration
by Marco André Ferreira Dias 28 Aug '05

28 Aug '05

Hy guys, I am doing a very long program (divided in diferent archives) that make some simplifications in indexed expressions. But if a declare a symbol variable completelly diferent in part of my program symbol x1("xi"); never used before, (yes, I checked if I declared this variable in main(), in other context..) this make diference im my output. In all functions declared in headers I am passing the simplified things as argument, so I think it not a symbol internal problem, like described in tutorial. My question: somebody got this behaviour before? if yes, what was resolved? Thanks for all Marco

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comparing ex
by Vera Louise Hauge 24 Aug '05

24 Aug '05

Hi, I want to compare (or test the equality of) two ex objects which contain symbols. a = a0 + x*a1; b = a0 + a1*x; If the ex objects are evaluated (symbolically), such that a-b becomes 0, then the test would be finished. However, how do I evaluate such a expression as a-b symbolically? Or are there other ways of comparing two such ex objects? Any suggestions on how to do this? Thanks, Vera Louise Hauge

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Re: GiNaC-list Digest, Vol 7, Issue 5
by Guangqiang Dong 23 Aug '05

23 Aug '05

Hi, Thanks for your suggestion. I updated the ancient version of bison, and it still got the same error. So I tried to see what is wrong with the readline library. The readline that ships with OS X is also an really old version 1.11. After updating it to the newest readline 5.0, GiNaC was installed successfully using DP. Best, Guangqiang On 23-Aug-05, at 6:00 AM, ginac-list-request(a)ginac.de wrote: > > ------------------------------ > > Message: 4 > Date: Tue, 23 Aug 2005 00:59:39 -0400 (EDT) > From: David Fang <fang(a)csl.cornell.edu> > Subject: Re: [GiNaC-list] ginsh_parser.yy error in Tiger. > To: GiNaC discussion list <ginac-list(a)ginac.de> > Message-ID: <20050823004542.Y140-100000(a)shannon.csl.cornell.edu> > Content-Type: TEXT/PLAIN; charset=US-ASCII > > >> I am trying to install GiNaC in Mac osx 10.4.2 (Tiger) using >> darwinports. The error I get is: >> > > Hi, > I haven't exactly had the best track record building CLN/GiNaC on > my Mac (sooooo close), but here's what I've found: > > ginsh_parser.cc builds for me, however, I'm using bison-2.0. It > also used > to build for me with bison-1.875. The bison that ships with OS X is > bison-1.28 (*ancient*) and is known to have problems, perhaps > including > generating bad code from ginsh_parser.yy. Tell us what "bison -- > version" > you have, and consider upgrading if you're using 1.28. > The rl_* functions come from readline. Those functions listed > below have been in libreadline since at least version 4 (I have 4.3 > installed), *BUT* the names did change slightly across minor > versions, as evidenced by the various #if's sprinkled about that > source > file. > HTH. > > >> ---> Building GiNaC with target all >> if g++ -DHAVE_CONFIG_H -I. -I. -I.. -I./../ginac -I../ginac - >> DIN_GINAC -I/opt/local/include -I/opt/local/include -I/opt/local/ >> include -g -O2 -MT ginsh_parser.o -MD -MP -MF ".deps/ >> ginsh_parser.Tpo" \ >> -c -o ginsh_parser.o `test -f 'ginsh_parser.cc' || echo >> './'`ginsh_parser.cc; \ >> then mv -f ".deps/ginsh_parser.Tpo" ".deps/ginsh_parser.Po"; \ >> else rm -f ".deps/ginsh_parser.Tpo"; exit 1; \ >> fi >> ginsh_parser.yy:48:6: error: missing binary operator before token >> "wrapper" >> ginsh_parser.yy:54:6: error: missing binary operator before token >> "wrapper" >> ginsh_parser.yy:837:6: error: missing binary operator before token >> "wrapper" >> ginsh_parser.yy:847:6: error: missing binary operator before token >> "wrapper" >> ginsh_parser.yy:899:6: error: missing binary operator before token >> "wrapper" >> ginsh_parser.yy: In function 'char** fcn_completion(const char*, int, >> int)': >> ginsh_parser.yy:835: error: invalid conversion from 'const char*' to >> 'char*' >> ginsh_parser.yy:840: error: 'rl_filename_completion_function' was not >> declared in this scope >> ginsh_parser.yy:840: error: 'rl_completion_matches' was not declared >> in this scope >> ginsh_parser.yy:850: error: 'rl_completion_matches' was not declared >> in this scope >> make[2]: *** [ginsh_parser.o] Error 1 >> make[1]: *** [all-recursive] Error 1 >> make: *** [all] Error 2 >> > > > David Fang > > > > > > ------------------------------ > > _______________________________________________ > GiNaC-list mailing list > GiNaC-list(a)ginac.de > http://thep.physik.uni-mainz.de/mailman/listinfo/ginac-list > > > End of GiNaC-list Digest, Vol 7, Issue 5 > **************************************** >

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ginsh_parser.yy error in Tiger.
by Guangqiang Dong 23 Aug '05

23 Aug '05

Hi, there, I am trying to install GiNaC in Mac osx 10.4.2 (Tiger) using darwinports. The error I get is: ---> Building GiNaC with target all Error: Target com.apple.build returned: shell command "cd "/opt/local/ var/db/dports/build/ file._opt_local_var_db_dports_sources_rsync.rsync.opendarwin.org_dpupdat e_dports_math_GiNaC/work/ginac-1.3.2" && make all" returned error 2 Command output: make all-recursive Making all in ginac make[2]: Nothing to be done for `all'. Making all in check make[2]: Nothing to be done for `all'. Making all in ginsh if g++ -DHAVE_CONFIG_H -I. -I. -I.. -I./../ginac -I../ginac - DIN_GINAC -I/opt/local/include -I/opt/local/include -I/opt/local/ include -g -O2 -MT ginsh_parser.o -MD -MP -MF ".deps/ ginsh_parser.Tpo" \ -c -o ginsh_parser.o `test -f 'ginsh_parser.cc' || echo './'`ginsh_parser.cc; \ then mv -f ".deps/ginsh_parser.Tpo" ".deps/ginsh_parser.Po"; \ else rm -f ".deps/ginsh_parser.Tpo"; exit 1; \ fi ginsh_parser.yy:48:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:54:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:837:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:847:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:899:6: error: missing binary operator before token "wrapper" ginsh_parser.yy: In function 'char** fcn_completion(const char*, int, int)': ginsh_parser.yy:835: error: invalid conversion from 'const char*' to 'char*' ginsh_parser.yy:840: error: 'rl_filename_completion_function' was not declared in this scope ginsh_parser.yy:840: error: 'rl_completion_matches' was not declared in this scope ginsh_parser.yy:850: error: 'rl_completion_matches' was not declared in this scope make[2]: *** [ginsh_parser.o] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 Guangqiang

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