<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><p style="font:14px/1.5 Lucida Grande;margin:0;">Dear <span style="white-space: pre-wrap;">Vladimir,</span></p><p style="font:14px/1.5 Lucida Grande;margin:0;"><br></p><p style="font:14px/1.5 Lucida Grande;margin:0;">Thanks very much for the quick reply!</p><p style="font:14px/1.5 Lucida Grande;margin:0;"><br></p><p style="font:14px/1.5 Lucida Grande;margin:0;">Indeed, when I remove the calchash method, I get the expected result.</p><p style="font:14px/1.5 Lucida Grande;margin:0;"><br></p><p style="font:14px/1.5 Lucida Grande;margin:0;">So when writting to an archive, GiNaC will use the hash internally, </p><p style="font:14px/1.5 Lucida Grande;margin:0;">and I still have a question,</p><p style="font-stretch: normal; line-height: 1.5; margin: 0px;">why does the first console output give the result: "<font color="#000000"><span style="caret-color: rgb(0, 0, 0); white-space: pre-wrap;">read: {k1^2,k2^2}”?</span></font></p><p style="font:14px/1.5 Lucida Grande;margin:0;"><br></p><p style="font:14px/1.5 Lucida Grande;margin:0;">Thanks again!</p><p style="font:14px/1.5 Lucida Grande;margin:0;"><br></p><p style="font:14px/1.5 Lucida Grande;margin:0;">Best regards!</p><p style="font:14px/1.5 Lucida Grande;margin:0;">Feng</p><span style="font: 14px/1.5 'Lucida Grande';color:#333;"><br></span><div class="foxmail_blockquote_fromhere_element" style="font: 12px/1.5 'Lucida Grande';padding:2px 0 2px 0;"> </div><div style="border-left: solid 3px #EAEAEA; padding-left: 10px"><div style="font: 12px/1.5 'PingFangSC-Regular';color:#70727B;">在 2021年12月18日 19:10，Vladimir V. Kisil<V.Kisil@leeds.ac.uk> 写道：</div><br><div class="mail_quote_55A04C4153304B51B7DB00ED5ED87BFB" style="font: 14px/1.5 'Lucida Grande';color:#333;"><pre style="white-space:pre-wrap;">>>>>> On Sat, 18 Dec 2021 16:22:22 +0800, Feng Feng <<a href="mailto:f.feng@outlook.com" title="mailto:f.feng@outlook.com">f.feng@outlook.com</a>> said:
FF> I got a strange behaviour while implementing the archive in
FF> user-defined class, to make the behaviour more explicitly, let
If you will delete the method Symbol::calchash() from your class you
will get the expected behaviour.
--
Vladimir V. Kisil <a href="http://www.maths.leeds.ac.uk/~kisilv/" title="http://www.maths.leeds.ac.uk/~kisilv/">http://www.maths.leeds.ac.uk/~kisilv/</a>
Book: Geometry of Mobius Maps <a href="https://doi.org/10.1142/p835" title="https://doi.org/10.1142/p835">https://doi.org/10.1142/p835</a>
Soft: Geometry of cycles <a href="http://moebinv.sourceforge.net/" title="http://moebinv.sourceforge.net/">http://moebinv.sourceforge.net/</a>
Jupyter notebooks: <a href="https://github.com/vvkisil?tab=repositories" title="https://github.com/vvkisil?tab=repositories">https://github.com/vvkisil?tab=repositories</a>
>>>>> On Sat, 18 Dec 2021 16:22:22 +0800, Feng Feng <<a href="mailto:f.feng@outlook.com" title="mailto:f.feng@outlook.com">f.feng@outlook.com</a>> said:
FF> Dear all,
FF> I got a strange behaviour while implementing the archive in
FF> user-defined class, to make the behaviour more explicitly, let
FF> me post the C++ code here:
FF> #include <ginac/ginac.h> #include <fstream>
FF> using namespace GiNaC; using namespace std;
FF> class Symbol : public symbol {
FF> GINAC_DECLARE_REGISTERED_CLASS(Symbol, symbol) public:
FF> Symbol(const string &s); void archive(archive_node & n) const
FF> override; void read_archive(const archive_node& n, lst& sym_lst)
FF> override; unsigned calchash() const override; };
FF> GINAC_DECLARE_UNARCHIVER(Symbol);
FF> GINAC_IMPLEMENT_REGISTERED_CLASS(Symbol, symbol)
FF> GINAC_BIND_UNARCHIVER(Symbol);
FF> const symbol & get_symbol(const string & s) { static map<string,
FF> symbol> dict; if (dict.find(s) == dict.end()) dict[s] =
FF> symbol(s); return dict[s]; }
FF> Symbol::Symbol() { } Symbol::Symbol(const string &s) :
FF> symbol(get_symbol(s)) { } int Symbol::compare_same_type(const
FF> basic &other) const { const Symbol &o = static_cast<const Symbol
FF> &>(other); int ret = get_name().compare(o.get_name());
FF> if(ret==0) return 0; else if(ret<0) return -1; else return 1; }
FF> void Symbol::archive(archive_node & n) const {
FF> inherited::archive(n); }
FF> void Symbol::read_archive(const archive_node& n, lst& sym_lst) {
FF> inherited::read_archive(n, sym_lst); *this = Symbol(get_name());
FF> }
FF> unsigned Symbol::calchash() const { static auto hash =
FF> symbol("_").gethash(); return hash; }
FF> int main() { Symbol k1("k1"), k2("k2"); auto garfn = "tmp.gar";
FF> { archive ar; ex val = lst{ k1*k1, k2*k2 };
FF> ar.archive_ex(val, "key"); ofstream out(garfn); out << ar;
FF> out.close(); cout << "writed: " << val << endl; } { archive ar;
FF> ifstream in(garfn); in >> ar; in.close(); auto val =
FF> ar.unarchive_ex(lst{}, "key"); cout << "read: " << val << endl;
FF> } // console output is // writed: {k1^2,k2^2} // read:
FF> {k1^2,k2^2}
FF> { archive ar; ex val = lst{ k1*k1==0, k2*k2==0 };
FF> ar.archive_ex(val, "key"); ofstream out(garfn); out << ar;
FF> out.close(); cout << "writed: " << val << endl; } { archive ar;
FF> ifstream in(garfn); in >> ar; in.close(); auto val =
FF> ar.unarchive_ex(lst{}, "key"); cout << "read: " << val << endl;
FF> } // console output is // writed: {k1^2==0,k2^2==0} // read:
FF> {k1^2==0,k1^2==0} // Note that the last line above, both items
FF> are the same: k1^2==0
FF> return 0; }
FF> Here I want to introduce a class Symbol, when one defines Symbol
FF> a(“a”), b(“a”);, then a and b will be the same or equal, so I
FF> override the method compare_same_type.
FF> The last console output seems very strange to me, the both items
FF> are the same, while the expected result is "read:
FF> {k1^2==0,k2^2==0}”.
FF> Thanks very much!
FF> Best regards! Feng
FF> ----------------------------------------------------
FF> Alternatives:
FF> ----------------------------------------------------
FF> _______________________________________________ GiNaC-list
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