August 2013 - GiNaC-list

Multiplication of Boolean variables
by tklam 02 Sep '13

02 Sep '13

Hi, I am implementing an arithmetic system for only Boolean variables based on GiNaC. May I know how I can modify the behaviour of symbolic multiplication such that: x*x == x (instead of x*x==x^2), and the multiplication of numeric remains unchanged (eg 3*4 == 12) ? Using subs(x^2 == x) works but I found it is slow if my expressions are huge and there are many symbols. Thank you very much. Best regards, argama

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GiNaC Match Documentation
by Mark Round 15 Aug '13

15 Aug '13

I have been encountering problems with the GiNaC function match. Basically I can not understand the documentation. I wanted to detail my story in the hope that perhaps my problems are solved and in the future someone else can avoid my pitfalls. The documentation informs me that I need an associative array. I can not find how to construct such an array elsewhere in the documentation so I assume that I am supposed to use exhashmap. That was a point of confusion for me. Then I designed the following code snipet, symbol x("x"), y("y"); ex tmp=x+y; exhashmap <ex> array; tmp.match(wild(1)+y); which apparently works fine. Now I wish to fill 'array' with the replacement table. So I modified to, tmp.match(wild(1)+y,array); which returned the following compiler messages, momentum_integration.cpp: In function ‘GiNaC::ex bring_to_parameterisable_form(GiNaC::ex)’: momentum_integration.cpp:13:33: error: no matching function for call to ‘GiNaC::ex::match(const GiNaC::ex, GiNaC::exhashmap<GiNaC::ex>&)’ momentum_integration.cpp:13:33: note: candidates are: In file included from /usr/include/ginac/ginac.h:30:0, from momentum_integration.h:14, from momentum_integration.cpp:1: /usr/include/ginac/ex.h:150:7: note: bool GiNaC::ex::match(const GiNaC::ex&) const /usr/include/ginac/ex.h:150:7: note: candidate expects 1 argument, 2 provided /usr/include/ginac/ex.h:151:7: note: bool GiNaC::ex::match(const GiNaC::ex&, GiNaC::exmap&) const /usr/include/ginac/ex.h:151:7: note: no known conversion for argument 2 from ‘GiNaC::exhashmap<GiNaC::ex>’ to ‘GiNaC::exmap& {aka std::map<GiNaC::ex, GiNaC::ex, GiNaC::ex_is_less>&}’ make: *** [momentum_integration.o] Error 1 I attempted to use the command exmap but I can not find anything on that in the documentation. I tried several permutations around, exmap <ex,ex> array; which made the compiler return, momentum_integration.cpp: In function ‘GiNaC::ex bring_to_parameterisable_form(GiNaC::ex)’: momentum_integration.cpp:11:8: error: ‘GiNaC::exmap {aka std::map<GiNaC::ex, GiNaC::ex, GiNaC::ex_is_less>}’ is not a template make: *** [momentum_integration.o] Error 1 At which point it is unclear to me what else I should try. The code was ran on a 64-bit Linux Mint-Debian distribution with ginac-1.6.2.

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ginac 1.6.2-2 on mingw-32.
by testhandle 07 Aug '13

07 Aug '13

(most of this text was written using google translate. english is not good at me. so there's a possibility that the meaning is not transmitted.) there may be unnecessary operation and defects. however, it is forced by this operation, but it have confirmed the operation of the tutorial examples. * step 0, dependencies. gmp 5.0.1 cln (gmp) 1.3.3 gcc 4.7.2 ld 2.23.1 m4 1.4.16 autoconf 2.68 autoreconf 2.68 automake 1.11 libtool 2.4 python 2.7.3 bison 2.4.2 flex 2.5.35 * step 1. $ git clone git://www.ginac.de/ginac.git * step 2, modify the 'ginac/config/config.rpath'. line 67: replace mingw* | pw32* | os2*) -> pw32* | os2*) line 57: insert mingw*) wl='Wl,' ;; line 135: replace cygwin* | mingw* | pw32*) -> cygwin* | pw32*) line 185: replace cygwin* | mingw* | pw32*) -> cygwin* | pw32*) line 199: replace linux*) -> linux* | mingw*) * step 3. $ cd ginac $ autoreconf -i * step 4, modify the 'ginac/configure'. line 15539: delete * step 5, modify the 'ginsh/ginsh_lexer.lpp'. line 37: replace #include "ginsh_parser.hpp" -> #include "ginsh_parser.h" * step 6. $ export CLN_LIBS="-L/usr/local/lib -lcln -lgmp" $ export CLN_CFLAGS="-I/usr/local/include" $ ./configure $ make $ make install * test 1. // hello.cpp ---------------- #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main() { symbol x("x"), y("y"); ex poly; for (int i=0; i<3; ++i) poly += factorial(i+16)*pow(x,i)*pow(y,2-i); cout << poly << endl; return 0; } $ g++ -c -O3 -I/usr/local/include -L/usr/local/bin hello.cpp $ g++ -o hello hello.o -lginac -lcln -lgmp &> result.txt $ ./hello 355687428096000*x*y+20922789888000*y^2+6402373705728000*x^2 * test 2. // hello2.cpp ---------------- #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; ex HermitePoly(const symbol & x, int n) { ex HKer=exp(-pow(x, 2)); // uses the identity H_n(x) == (-1)^n exp(x^2) (d/dx)^n exp(-x^2) return normal(pow(-1, n) * diff(HKer, x, n) / HKer); } int main() { symbol z("z"); for (int i=0; i<6; ++i) cout << "H_" << i << "(z) == " << HermitePoly(z,i) << endl; return 0; } $ g++ -c -O3 -I/usr/local/include -L/usr/local/bin hello2.cpp $ g++ -o hello2 hello2.o -lginac -lcln -lgmp &> result.txt $ ./hello2 H_0(z) == 1 H_1(z) == 2*z H_2(z) == -2+4*z^2 H_3(z) == -12*z+8*z^3 H_4(z) == 12+16*z^4-48*z^2 H_5(z) == 120*z+32*z^5-160*z^3

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