January 2007 - GiNaC-list

collecting on similar series expansion
by Charlls Quarra 01 Feb '07

01 Feb '07

Hi , I'm just trying out ginac for the first time. I have an expression with sumands of this type (in latex format): 1-\frac{1}{3} \frac{ p D[0](F)(q) D[0,0](F)(q) \nu \epsilon^{2} dt^{5} \delta}{m^{3}}-\frac{1}{9} \frac{ p D[0](F)(q) D[0,0](F)(q)^{2} \alpha^{2} \nu^{2} \epsilon^{2} dt^{9} \F(q) \delta \gamma}{m^{5}}-\frac{1}{18} \frac{ p^{2} D[0,0](F)(q) D[0,0,0](F)(q) \beta \alpha^{2} \epsilon^{2} dt^{8} \F(q) \delta \gamma}{m^{5}}+\frac{1}{2} \frac{ D[0](F)(q) D[0,0](F)(q) \alpha \nu \epsilon dt^{6} \F(q)}{m^{3}} .... so i want to collect terms that have the same coefficients of the form D[0..i times] (F)(q) * D[ 0.. j times] (F)(q) .... but the polynomial collect won't work. Initially i thought about substituting each D[ ] (F)(q) with a different symbol, then collect on the multivariate polynomials of these symbols and then finally substitute back the D[] expressions, however, I don't know how the collect call is supposed to receive the symbols that it must collect, the code looks like this: ex jacobian = diff( q + dq_new*dt , q )*diff( p + dp_new*dt , p ) - diff( q + dq_new*dt , p )*diff( p + dp_new*dt , q ); cout << " the jacobian of the integrator is " << expand(jacobian) << endl; exmap diff_map , inv_diff_map; symbol foo[10]; diff_map[ F(q) ] = foo[0]; inv_diff_map[ foo[0] ] = F(q); diff_map[ F(q).diff(q) ] = foo[1]; inv_diff_map[ foo[1] ] = F(q).diff(q); diff_map[ F(q).diff(q,2) ] = foo[2]; inv_diff_map[ foo[2] ] = F(q).diff(q,2); diff_map[ F(q).diff(q,3) ] = foo[3]; inv_diff_map[ foo[3] ] = F(q).diff(q,3); diff_map[ F(q).diff(q,4) ] = foo[4]; inv_diff_map[ foo[4] ] = F(q).diff(q,4); ex rord = collect( jacobian.subs( diff_map ) , { foo[0] , foo[1] , foo[2] , foo[3] , foo[4] } ); // i know this is an error in C++, but this is the idea rord = rord.subs( inv_diff_map ); cout << "reordered we obtain " << rord << endl; any thoughts on this? __________________________________________________ Preguntá. Respondé. Descubrí. Todo lo que querías saber, y lo que ni imaginabas, está en Yahoo! Respuestas (Beta). ¡Probalo ya! http://www.yahoo.com.ar/respuestas

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I'm ready for the new release.
by Chris Dams 01 Feb '07

01 Feb '07

Dear all, I applied the patch that I was talking about. The points are (1) Added a simplification rules for powers that turns (x^a)^b into x^(a*b) in the case that x is positive and a is real. (2) Improved expansion of powers. In the case that a power is raised to an integer power, we should not simply be doing (x^a)^n -> expair(x, a*n) because this is wrong if x=y^2, a=1/2 and n=2. Then we get ((y^2)^(1/2))^2 -> expair(y^2, 1), which should be expair(y, 2). Happy releasing, Chris

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retrieving wildcard replacements on C++
by Charlls Quarra 01 Feb '07

01 Feb '07

Hi, suppose the following: symbol x("x"); ex foo = A*pow(x,2) + B*x; lst ocurrences; foo.find( wild(1)*x , ocurrences ); //the wildcard replacement is B how would you retrieve the wildcard replacement in this case? in ginsh you already get a list of the wildcards replacement, but after reading various times the relevant page of the tutorial, i couldn't find how is this done in c++ cheers __________________________________________________ Preguntá. Respondé. Descubrí. Todo lo que querías saber, y lo que ni imaginabas, está en Yahoo! Respuestas (Beta). ¡Probalo ya! http://www.yahoo.com.ar/respuestas

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array expressions with symbolic index
by Zhongxing Xu 01 Feb '07

01 Feb '07

Hello, Is there something like array expression in GiNaC? I want to do symbolic computation involving array expressions related to program verification. I would like to implement a theorem prover on top of GiNaC. So I also need conditional expressions. For example: x = mem[2] + 2; y = mem[i] -3; x >= 3; Can GiNaC represent these expressions? Note that array index might be a symbolic value. Thank you. - Zhongxing Xu

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Problems
by Jonathan Heinen 31 Jan '07

31 Jan '07

Hi, i want to use ginac as a lib under Mac OS X 10.4..8. I compiled cln 1.1.13 without problems. But compiling ginac 1.3.6 gave me the well known ginsh_parser.yy error: if g++ -DHAVE_CONFIG_H -I. -I. -I.. -I./../ginac -I../ginac - DIN_GINAC -I/usr/local/include -g -O2 -MT ginsh_parser.o -MD -MP - MF ".deps/ginsh_parser.Tpo" -c -o ginsh_parser.o 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:50:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:56:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:860:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:870:6: error: missing binary operator before token "wrapper" ginsh_parser.yy:922:6: error: missing binary operator before token "wrapper" ginsh_parser.yy: In function 'char** fcn_completion(const char*, int, int)': ginsh_parser.yy:859: error: invalid conversion from 'const char*' to 'char*' ginsh_parser.yy:869: error: invalid conversion from 'const char*' to 'char*' make[2]: *** [ginsh_parser.o] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 I'm using gcc --version i686-apple-darwin8-gcc-4.0.1 (GCC) 4.0.1 (Apple Computer, Inc. build 5363) Copyright (C) 2005 Free Software Foundation, Inc. and yacc --version bison (GNU Bison) 2.3 Written by Robert Corbett and Richard Stallman. Is there another thing i have to instal? O shold i use a different version of gcc/Yacc? Thanks Jonathan

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Bug report: Can't construct an expression from a string
by Mitch Watrous 20 Jan '07

20 Jan '07

Hello. After the latest version of GiNaC was installed on my machine, my programs are no longer able to construct an expression from a string. I am using version 1.3.6-1.fc5 of GiNaC. My operating system is Fedora Core 5, and I am using version 4.1.1 of the gcc compiler. Here is the code that causes the error, which is based on the example code from the GiNaC tutorial section on expression input: #include <ginac/ginac.h> int main() { using namespace GiNaC; symbol x("x"), y("y"); ex e("2*x+sin(y)", lst(x, y)); return 0; } Here is the error message I get when I execute the program main: terminate called after throwing an instance of 'std::runtime_error' what(): syntax error, unexpected ')' at ) Aborted Here is my Makefile: LDFLAGS = -L/usr/lib CPPFLAGS = -g -I/usr/include CC = g++ LIBS = -lcln -lginac main_OBJ = main.o .PHONY: all clean all: $(MAKE) main clean: -rm $(main_OBJ) -rm main -rm -rf ./tmp main: $(main_OBJ) $(CC) $(LDFLAGS) $^ -o $@ $(LIBS) %.o: %.cpp $(CC) -c $(CPPFLAGS) $(CFLAGS) $< Thanks for your help, Mitch Watrous

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Re: GiNaC-list Digest, Vol 22, Issue 5
by Eric Collins 06 Jan '07

06 Jan '07

Thank you for your assistance. I was able to properly serialize the ex class using char arrays, facilitated by the I/O capabilities of the archive class. Eric M. Collins On 12/24/06, ginac-list-request(a)ginac.de <ginac-list-request(a)ginac.de> wrote: > > 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. Serialization of datatypes (Eric Collins) > 2. Re: Serialization of datatypes (Chris.Dams(a)mi.infn.it) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 23 Dec 2006 10:14:51 -0600 > From: "Eric Collins" <emc2(a)ra.msstate.edu> > Subject: [GiNaC-list] Serialization of datatypes > To: ginac-list(a)ginac.de > Message-ID: > <805f78150612230814k3689154epd1d3f1bb5905992(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Would anyone be interested in helping me figure out how to serialize the > datatypes in GiNaC/CLN/GMP? I've looked at the source headers for some of > the datatypes and the use of reference counted pointers everywhere makes > this seem like a non-trivial task. > > I need to be able to pack all data relevant to a particular instantiation > of > a datatype (e.g. numeric or pseries), into a contiguous array. This data > would then be passed to another process where it would be unpacked into a > new instantiation of the same datatype. > > Any help, or suggestions of where to begin looking for relevant > information > would be much appreciated. > > Eric M. Collins > -- > Ad Astra Per Aspera >

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