September 2004 - GiNaC-devel

symbolic integration.
by Chris Dams 12 Oct '04

12 Oct '04

Dear all, Here's a patch plus two new files for GiNaC that add a class to symbolically represent an integral. Details can be found in the patch, since it also patches the documentation. Best, Chris

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problem with dbgprint.
by Chris Dams 06 Oct '04

06 Oct '04

Dear all, I found out that the program #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main(int argc, char** argv) { symbol x("x"); ex_to<power>(x*x).dbgprint(); return 0; } gives the output [power object] This is because in basic::dbgprint a print_context is constructed from std::cerr and not a print_dflt. Changing, in basic::dbgprint, the line this->print(std::cerr); into this->print(print_dflt(std::cerr)); solves this problem. Now the output is x^2 as expected. Best, Chris

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segmentation fault in substituting.
by Chris Dams 30 Sep '04

30 Sep '04

Dear GiNaCers, I found that basic::subs_one_level sometimes gives a segementation fault. This is because the branch that takes care of the no_pattern option, tries to find *this in the exmap that contains the substitution. This invokes the construction of a temporary ex from *this. If it turns out that .eval() wants to change the ex in something else, the this pointer is going to be deleted, because, presumably, it was allocated with the dynallocated flag set, by basic::subs. If no substitution is found, it is tried to return the just deleted this pointer. Not a good idea... I suggest the change below in the basic::subs_one_level function in basic.cpp. *************** *** 603,611 **** exmap::const_iterator it; if (options & subs_options::no_pattern) { ! it = m.find(*this); if (it != m.end()) return it->second; } else { for (it = m.begin(); it != m.end(); ++it) { lst repl_lst; --- 617,627 ---- exmap::const_iterator it; if (options & subs_options::no_pattern) { ! ex thisex=*this; ! it = m.find(thisex); if (it != m.end()) return it->second; + return thisex; } else { for (it = m.begin(); it != m.end(); ++it) { lst repl_lst; Best, Chris

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(no subject)
by Vladimir Kisil 26 Sep '04

26 Sep '04

Dear All, I wish to propose a further patches for clifford.cpp and clifford.h. Its make: 1. Fixes a nasty behaviour when a simplification creates nested indexed objects like (eta.psi.xi).nu.mu. 2. Contains two new functions described in the clifford.h. Hope they will be useful, at least I employ them to create some graphics of conformal maps already. 3. Other bits are small improvements and spaces fixed. I hope to contribute some documentation for expanded clifford.cpp as well. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk -- www: http://maths.leeds.ac.uk/~kisilv/ Index: ginac/clifford.h =================================================================== RCS file: /home/cvs/GiNaC/ginac/clifford.h,v retrieving revision 1.51 diff -r1.51 clifford.h 278c278 < ex delete_ONE(const ex &e); --- > ex delete_ONE(const ex & e); 294a295,318 > /** An inverse function to lst_to_clifford(). For given Clifford vector extracts > * its components with respect to given Clifford unit. Obtained components may > * contain Clifford units with a different metric. Extraction is based on > * the algebraic formula (e * c.i + c.i * e)/ pow(e.i, 2) for non-degenerate cases > * (i.e. neither pow(e.i, 2) = 0). > * > * @param e Clifford expresion to be decomposed into components > * @param c Clifford unit defining the metric for splitting (should have numeric dimension of indices) > * @param algebraic Use algebraic or symbolic algorythm for extractions */ > lst clifford_to_lst(const ex & e, const ex & c, bool algebraic=true); > > /** Calculations of Moebius transformations (conformal map) defined by a 2x2 Clifford matrix > * (a b\\c d) in linear spaces with arbitrary signature. The expression is > * (a * x + b)/(c * x + d), where x is a vector buid from list v with metric G. > * (see Jan Cnops. An introduction to {D}irac operators on manifolds, v.24 of > * Progress in Mathematical Physics. Birkhauser Boston Inc., Boston, MA, 2002.) > * > * @param a (1,1) entry of the defining matrix > * @param b (1,2) entry of the defining matrix > * @param c (2,1) entry of the defining matrix > * @param d (2,2) entry of the defining matrix > * @param v Vector to be transformed > * @param G Metric of the surrounding space */ > ex moebius(const ex & a, const ex & b, const ex & c, const ex & d, const ex & v, const ex & G); Index: ginac/clifford.cpp =================================================================== RCS file: /home/cvs/GiNaC/ginac/clifford.cpp,v retrieving revision 1.79 diff -r1.79 clifford.cpp 680c680,685 < return clifford(unit, mu, metr, rl); --- > if (is_a<indexed>(metr)) > return clifford(unit, mu, metr.op(0), rl); > else if(is_a<tensmetric>(metr) || is_a<matrix>(metr)) > return clifford(unit, mu, metr, rl); > else > throw(std::invalid_argument("metric for Clifford unit must be of type indexed, tensormetric or matrix")); 990c995 < ex clifford_prime(const ex &e) --- > ex clifford_prime(const ex & e) 1005c1010 < ex delete_ONE(const ex &e) --- > ex delete_ONE(const ex & e) 1022c1027 < ex clifford_norm(const ex &e) --- > ex clifford_norm(const ex & e) 1024c1029 < return sqrt(delete_ONE((e * clifford_bar(e)).simplify_indexed())); --- > return sqrt(delete_ONE(canonicalize_clifford(e * clifford_bar(e)).simplify_indexed())); 1027c1032 < ex clifford_inverse(const ex &e) --- > ex clifford_inverse(const ex & e) 1031a1037,1038 > else > throw(std::invalid_argument("Cannot find inverse of Clifford number with zero norm!")); 1068a1076,1158 > /** Auxiliary structure to define a function for striping one Clifford unit > * from vectors. Used in clifford_to_lst(). */ > ex get_clifford_comp(const ex & e, const ex & c) > { > pointer_to_map_function_1arg<const ex &> fcn(get_clifford_comp, c); > > if (is_a<add>(e)) > return e.map(fcn); > else if (is_a<ncmul>(e) || is_a<mul>(e)) { > //find a Clifford unit with the same metric, delete it and substitute its index > size_t ind = e.nops() + 1; > for (size_t j = 0; j < e.nops(); j++) > if (is_a<clifford>(e.op(j)) && ex_to<clifford>(c).same_metric(e.op(j))) > if (ind > e.nops()) > ind = j; > else > throw(std::invalid_argument("Expression is a Clifford multi-vector")); > if (ind < e.nops()) { > ex S = 1; > for(size_t j=0; j < e.nops(); j++) > if (j != ind) { > exvector ind_vec = ex_to<indexed>(e.op(j)).get_dummy_indices(ex_to<indexed>(e.op(ind))); > if (ind_vec.size() > 0) { > exvector::const_iterator it = ind_vec.begin(), itend = ind_vec.end(); > while (it != itend) { > S = S * e.op(j).subs(ex_to<varidx>(*it) == ex_to<idx>(c.op(1)).get_value()); > it++; > } > } else > S = S * e.op(j); > } > return S; > } else > throw(std::invalid_argument("Expression is not a Clifford vector to the given units")); > } else { > throw(std::invalid_argument("Expression is not handlable as a Clifford vector")); > } > } > > > lst clifford_to_lst (const ex & e, const ex & c, bool algebraic) > { > GINAC_ASSERT(is_a<clifford>(c)); > varidx mu = ex_to<varidx>(c.op(1)); > if (! mu.is_dim_numeric()) > throw(std::invalid_argument("Index should have a numeric dimension")); > unsigned int D = ex_to<numeric>(mu.get_dim()).to_int(); > > if (algebraic) // check if algebraic method is applicable > for (unsigned int i = 0; i < D; i++) > if (pow(c.subs(mu == i), 2) == 0) > algebraic = false; > lst V; > if (algebraic) > for (unsigned int i = 0; i < D; i++) > V.append(delete_ONE(simplify_indexed(canonicalize_clifford(e * c.subs(mu == i) + c.subs(mu == i) * e))/(2*pow(c.subs(mu == i), 2)))); > else { > ex e1 = canonicalize_clifford(e); > for (unsigned int i = 0; i < D; i++) > V.append(get_clifford_comp(e1, c.subs(c.op(1) == i))); > } > return V; > } > > > ex moebius(const ex & a, const ex & b, const ex & c, const ex & d, const ex & v, const ex & G) > { > ex x, D; > if (is_a<indexed>(G)) > D = ex_to<varidx>(G.op(1)); > else > throw(std::invalid_argument("metric should be an indexed object")); > > varidx mu ((new symbol)->setflag(status_flags::dynallocated), ex_to<varidx>(D).get_dim()); > > if (! is_a<matrix>(v) && ! is_a<lst>(v)) > throw(std::invalid_argument("parameter v should be either vector or list")); > > x = lst_to_clifford(v, mu, G); > ex e = simplify_indexed(canonicalize_clifford((a * x + b) * clifford_inverse(c * x + d))); > ex cu = clifford_unit(mu, G); > return clifford_to_lst(e, cu); > }

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patch for power
by Chris Dams 24 Sep '04

24 Sep '04

Dear all, I found that the program #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main(int argc, char** argv) { symbol x("x"),y("y"); ex e=sin(x)*sin(x); if(e.info(info_flags::polynomial)) cout << e << " is polynomial" << endl; else cout << e << " is not polynomial" << endl; e=sin(x)*sin(y); if(e.info(info_flags::polynomial)) cout << e << " is polynomial" << endl; else cout << e << " is not polynomial" << endl; return 0; } gives the output sin(x)^2 is polynomial sin(x)*sin(y) is not polynomial which I find very awkward. The attached patch unpolynomializes sin(x)^2. Best, Chris

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GiNaC-1.2.3 and nestedsums-1.4.5 on Mac OS X
by Gregory Wright 07 Sep '04

07 Sep '04

Hi, Since Bruno Haible posted his patches to cln-1.1.8, it's built cleanly on Mac OS X, and allowed me to build GiNaC-1.2.3. On my machine, an 800 MHz tiBook running OS X 10.3.5, and using g++ 3.3 from Xcode 1.5, it passes all the tests in 'make check'. When I try to build nestedsums-1.4.5, I get build failures caused by the inability to adjust pointers in convariant returns: make all-recursive Making all in nestedsums if /bin/sh ../libtool --mode=compile g++ -DHAVE_CONFIG_H -I. -I. -I.. -I/opt/local/include -I/opt/local/include -I/opt/local/include -I/opt/local/include -g -O2 -MT root_of_unity.lo -MD -MP -MF ".deps/root_of_unity.Tpo" -c -o root_of_unity.lo root_of_unity.cc; \ then mv -f ".deps/root_of_unity.Tpo" ".deps/root_of_unity.Plo"; else rm -f ".deps/root_of_unity.Tpo"; exit 1; fi g++ -DHAVE_CONFIG_H -I. -I. -I.. -I/opt/local/include -I/opt/local/include -I/opt/local/include -I/opt/local/include -g -O2 -MT root_of_unity.lo -MD -MP -MF .deps/root_of_unity.Tpo -c root_of_unity.cc -fno-common -DPIC -o .libs/root_of_unity.o Euler_Zagier_sum.h:48: sorry, unimplemented: adjusting pointers for covariant returns Euler_Zagier_sum.h:48: sorry, unimplemented: adjusting pointers for covariant returns harmonic_sum.h:49: sorry, unimplemented: adjusting pointers for covariant returns harmonic_sum.h:49: sorry, unimplemented: adjusting pointers for covariant returns multiple_polylog.h:54: sorry, unimplemented: adjusting pointers for covariant returns multiple_polylog.h:54: sorry, unimplemented: adjusting pointers for covariant returns harmonic_polylog.h:50: sorry, unimplemented: adjusting pointers for covariant returns (There are more header files that it complains about; I can send the full output if you wish.) I emailed Stefan Weinzierl and he pointed out that this comes from the macros GINAC_DECLARE_REGISTERED_CLASS and GINAC_IMPLEMENT_REGISTERED_CLASS Two questions: 1. Is there a workaround for this? (Since I am trying to port xloops/nestedsums/GiNac/cln to the darwinports system, I would prefer no to have to add build another g++ compiler. I could, if absolutely necessary, do that.) 2. Why does this happen for the nestedsums library and not for GiNaC? Does GiNaC allow covariant returns but not actually use them? Any help is appreciated. Best Wishes, Greg Gregory Wright Antiope Associates gwright(a)antiope.com

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