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[SCM] GiNaC -- a C++ library for symbolic computations branch, ginac_1-4, updated. release_1-4-0-53-g1043ee1
by git＠ginac.de 17 Jul '08

17 Jul '08

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, ginac_1-4 has been updated via 1043ee1e38b7a70e737870e6b87f07607c0e9639 (commit) from 165d6495d53e1af1073a88a3640a6f364dcb5e9b (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 1043ee1e38b7a70e737870e6b87f07607c0e9639 Author: Richard B. Kreckel <kreckel(a)ginac.de> Date: Tue Jul 15 23:57:43 2008 +0200 documentation: it is get_dim(), not get_dimension() This was misdocumented ever since GiNaC-0.8.0. ----------------------------------------------------------------------- Summary of changes: doc/tutorial/ginac.texi | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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Questions about expairseq::match().
by Alexei Sheplyakov 15 Jul '08

15 Jul '08

Hi! I've stumbled upon the following code in ginac/exparseq.cpp:expairseq::match() 422 // Now, for every term of the pattern, look for a matching term in 423 // the expression and remove the match 424 for (size_t i=0; i<pattern.nops(); i++) { 425 ex p = pattern.op(i); 426 if (has_global_wildcard && p.is_equal(global_wildcard)) 427 continue; 428 exvector::iterator it = ops.begin(), itend = ops.end(); 429 while (it != itend) { So far so good... 430 lst::const_iterator last_el = repl_lst.end(); 431 --last_el; 432 if (it->match(p, repl_lst)) { 433 ops.erase(it); 434 goto found; 435 } This fragment looks a bit confusing. it->match(p, repl_lst) can change repl_lst, so iterators become invalid. Fortunately, in that case match returns true, so we jump out of the loop. So, we can initialize the iterator last_el *after* checking for possible matches, like this: if (it->match(p, repl_lst)) { ops.erase(it); goto found; } lst::const_iterator last_el = repl_lst.end(); --last_el; Unless I'm missing something this code is equivalent to the previous variant, but it's more readable (i.e. no confusion about possible invalidation of last_el iterator). 436 while(true) { 437 lst::const_iterator next_el = last_el; 438 ++next_el; 439 if(next_el == repl_lst.end()) 440 break; 441 else 442 repl_lst.remove_last(); 443 } There's definitely something fishy about this chunk. First of all, it seems like next_el at the line 439 is always repl_lst.end(), so this code doesn't do anything at all. Secondly, if it next_el ever changes its value from repl_lst.end(), repl_lst.remove_last() invalidates iterators (both next_el *and* last_el), so the result of next iteration is unpredictable. So, the questions are: 1. What I'm missing here? 2. What is the actual purpose of this code (lines 436 -- 443)? 3. According to git-blame, this (a little bit strange) code was introduced by commit 73f0ce4cf8d91f073f35a45443f5fbe886921c5c. The commit message says: "Fixed bug in ::match." What was the bug in first place? Could anyone please enlighten me? Best regards, Alexei -- All science is either physics or stamp collecting.

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-48-gcb078db
by git＠ginac.de 15 Jul '08

15 Jul '08

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via cb078dba2a491d80a34924b29bd8d3992c18b7fe (commit) from 37d324b137fcb61384203b711e91d8919535f237 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit cb078dba2a491d80a34924b29bd8d3992c18b7fe Author: Alexei Sheplyakov <varg(a)theor.jinr.ru> Date: Mon Jul 14 17:46:25 2008 +0400 clifford_unit: fix possible bugs due to wrong operator[!=]= usage. ----------------------------------------------------------------------- Summary of changes: ginac/clifford.cpp | 17 ++++++++++++++--- 1 files changed, 14 insertions(+), 3 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations branch, ginac_1-4, updated. release_1-4-0-52-g165d649
by git＠ginac.de 25 Jun '08

25 Jun '08

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, ginac_1-4 has been updated via 165d6495d53e1af1073a88a3640a6f364dcb5e9b (commit) from 9968ebfc60c121b8373f270d79f08d85ca37ccb5 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 165d6495d53e1af1073a88a3640a6f364dcb5e9b Author: Jens Vollinga <jensv(a)nikhef.nl> Date: Wed Jun 25 11:28:11 2008 +0200 Removed left-over debugging line. ----------------------------------------------------------------------- Summary of changes: check/exam_clifford.cpp | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-47-g37d324b
by git＠ginac.de 25 Jun '08

25 Jun '08

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via 37d324b137fcb61384203b711e91d8919535f237 (commit) from 26c31eb89fe38c4d232f90b62c8acbeaaa0454f4 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 37d324b137fcb61384203b711e91d8919535f237 Author: Jens Vollinga <jensv(a)nikhef.nl> Date: Wed Jun 25 11:28:11 2008 +0200 Removed left-over debugging line. ----------------------------------------------------------------------- Summary of changes: check/exam_clifford.cpp | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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Patches
by Jens Vollinga 25 Jun '08

25 Jun '08

Hi all, I just put the gcd patch (2008-04-24) and the clifford patch (2008-04-26) into the public repository. For the clifford patch I had to change additionally three lines in clifford.cpp (removing the static keywords). Somehow wrong information is kept there, which causes an exception if more than one clifford_unit with different dimensions is to be created. Regards, Jens

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-46-g26c31eb
by git＠ginac.de 25 Jun '08

25 Jun '08

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via 26c31eb89fe38c4d232f90b62c8acbeaaa0454f4 (commit) via fd4fbeaa409cd807e4f2f7501d278e835e964d69 (commit) from 6850c16435de33396ccd505ff26b4d4574fa74cf (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 26c31eb89fe38c4d232f90b62c8acbeaaa0454f4 Author: Jens Vollinga <jensv(a)nikhef.nl> Date: Wed Jun 25 11:17:55 2008 +0200 Make the behaviour of class function more consistent with respect to ncmul::eval(). [V.Kisil] commit fd4fbeaa409cd807e4f2f7501d278e835e964d69 Author: Jens Vollinga <jensv(a)nikhef.nl> Date: Tue Jun 24 21:26:58 2008 +0200 Improve heur_gcd() so it can handle rational polynomials, and add a test case. Previously heur_gcd() worked only with integer polynomials, and did not check if the inputs are indeed integer polynomials. That lead to an endless loop or a miscomputed gcd. [A.Sheplyakov] ----------------------------------------------------------------------- Summary of changes: check/Makefile.am | 4 ++ check/exam_clifford.cpp | 17 ++++++++ check/heur_gcd_bug.cpp | 39 +++++++++++++++++++ ginac/clifford.cpp | 11 ++++- ginac/function.pl | 11 +++++ ginac/normal.cpp | 96 ++++++++++++++++++++++++++++++++++++++-------- 6 files changed, 158 insertions(+), 20 deletions(-) create mode 100644 check/heur_gcd_bug.cpp hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations branch, ginac_1-4, updated. release_1-4-0-51-g9968ebf
by git＠ginac.de 25 Jun '08

25 Jun '08

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, ginac_1-4 has been updated via 9968ebfc60c121b8373f270d79f08d85ca37ccb5 (commit) via 65196b339fbcc7d0e2eb3036fa64e5fa47b56379 (commit) from 314595d10b4a4471bd4637a9038b18dde4780513 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 9968ebfc60c121b8373f270d79f08d85ca37ccb5 Author: Jens Vollinga <jensv(a)nikhef.nl> Date: Wed Jun 25 11:17:55 2008 +0200 Make the behaviour of class function more consistent with respect to ncmul::eval(). [V.Kisil] commit 65196b339fbcc7d0e2eb3036fa64e5fa47b56379 Author: Jens Vollinga <jensv(a)nikhef.nl> Date: Tue Jun 24 21:26:58 2008 +0200 Improve heur_gcd() so it can handle rational polynomials, and add a test case. Previously heur_gcd() worked only with integer polynomials, and did not check if the inputs are indeed integer polynomials. That lead to an endless loop or a miscomputed gcd. [A.Sheplyakov] ----------------------------------------------------------------------- Summary of changes: check/Makefile.am | 4 ++ check/exam_clifford.cpp | 17 ++++++++ check/heur_gcd_bug.cpp | 39 +++++++++++++++++++ ginac/clifford.cpp | 11 ++++- ginac/function.pl | 11 +++++ ginac/normal.cpp | 96 ++++++++++++++++++++++++++++++++++++++-------- 6 files changed, 158 insertions(+), 20 deletions(-) create mode 100644 check/heur_gcd_bug.cpp hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[PATCH] Function and ncmul
by Vladimir Kisil 26 Apr '08

26 Apr '08

Dear All, Consider the following program: #include <ginac/ginac.h> #include <fstream> using namespace std; using namespace GiNaC; int main(){ realsymbol a("a"); varidx mu(symbol("mu", "\\mu"), 1); ex e = clifford_unit(mu, diag_matrix(lst(-1))), e0=e.subs(mu==0); cout << e0*e0*exp(a*e0) << endl; // -> exp(e0*a) cout << exp(a*e0)*e0*e0 << endl; // -> exp(e0*a)*e0*e0 } The expression in the second output is not simplified for the following reason. When the method ncmul::eval() collects non-commuting terms, the function exp(e0*a) gets the type of its first noncommuting argument, i.e. e0 (this is defined by function::return_type()). So all three factors are of the same type. However, later on, when ncmul::eval() calls the method eval_ncmul() for the first term in the product, e.i. exp(e0*a), it falls back to basic::eval_ncmul() not clifford::eval_ncmul() as one may expect. I am providing below a small patch which makes the behaviour of class function more consistent in this respect. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk -- www: http://maths.leeds.ac.uk/~kisilv/ Parent: 6850c16435de33396ccd505ff26b4d4574fa74cf (Fixed bug in mLi summation causing premature drop-out and made Nielsen polylog) Branch: master Follows: release_1-4-0 Precedes: Method function::eval_ncmul() is defined to match the behaviour of function::return_type() ------------------------------ ginac/function.pl ------------------------------ index e91278c..3b22143 100644 @@ -507,6 +507,7 @@ public: ex expand(unsigned options=0) const; ex eval(int level=0) const; ex evalf(int level=0) const; + ex eval_ncmul(const exvector & v) const; unsigned calchash() const; ex series(const relational & r, int order, unsigned options = 0) const; ex thiscontainer(const exvector & v) const; @@ -1053,6 +1054,16 @@ ${evalf_switch_statement} throw(std::logic_error("function::evalf(): invalid nparams")); } +/* +* This method is defined to be in line with behaviour of function::return_type() +*/ +ex function::eval_ncmul(const exvector & v) const +{ + // If this function is called then the list of arguments is non-empty + // and the first argument is non-commutative, see function::return_type() + return seq.begin()->eval_ncmul(v); +} + unsigned function::calchash() const { unsigned v = golden_ratio_hash(golden_ratio_hash((p_int)tinfo()) ^ serial);

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Function and ncmul
by Vladimir V. Kisil 26 Apr '08

26 Apr '08

Dear All, Consider the following program: #include <ginac/ginac.h> #include <fstream> using namespace std; using namespace GiNaC; int main(){ realsymbol a("a"); varidx mu(symbol("mu", "\\mu"), 1); ex e = clifford_unit(mu, diag_matrix(lst(-1))), e0=e.subs(mu==0), p1=e0*exp(a*e0), p2=exp(a*e0)*e0; cout << e0*p1 << endl; // -> exp(e0*a) cout << p2*e0 << endl; // -> exp(e0*a)*e0*e0 } The expression in the second output is not simplified for the following reason. When the method ncmul::eval() collects non-commuting the terms exp(e0*a) gets the type of its first noncommuting element, i.e. e0 (this is defined by function::return_type()). So all three factors are in the same type group. However when later ncmul::eval() calls the method eval_ncmul() for the first term in the product, e.i. exp(e0*a), it falls back to basic::eval_ncmul() not clifford::eval_ncmul() as one may expect. I provide below a small patch which makes the behaviour of class function more consistent in this respect. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk -- www: http://maths.leeds.ac.uk/~kisilv/ Parent: 6850c16435de33396ccd505ff26b4d4574fa74cf (Fixed bug in mLi summation causing premature drop-out and made Nielsen polylog) Branch: master Follows: release_1-4-0 Precedes: Method function::eval_ncmul() is defined to match the behaviour of function::return_type() ------------------------------ ginac/function.pl ------------------------------ index e91278c..3b22143 100644 @@ -507,6 +507,7 @@ public: ex expand(unsigned options=0) const; ex eval(int level=0) const; ex evalf(int level=0) const; + ex eval_ncmul(const exvector & v) const; unsigned calchash() const; ex series(const relational & r, int order, unsigned options = 0) const; ex thiscontainer(const exvector & v) const; @@ -1053,6 +1054,16 @@ ${evalf_switch_statement} throw(std::logic_error("function::evalf(): invalid nparams")); } +/* +* This method is defined to be in line with behaviour of function::return_type() +*/ +ex function::eval_ncmul(const exvector & v) const +{ + // If this function is called then the list of arguments is non-empty + // and the first argument is non-commutative, see function::return_type() + return seq.begin()->eval_ncmul(v); +} + unsigned function::calchash() const { unsigned v = golden_ratio_hash(golden_ratio_hash((p_int)tinfo()) ^ serial);

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