exam_misc \
exam_mod_gcd \
bugme_chinrem_gcd \
+ pgcd_relatively_prime_bug \
exam_cra
TIMES = time_dennyfliegner \
bugme_chinrem_gcd_SOURCES = bugme_chinrem_gcd.cpp
bugme_chinrem_gcd_LDADD = ../ginac/libginac.la
+pgcd_relatively_prime_bug_SOURCES = pgcd_relatively_prime_bug.cpp
+pgcd_relatively_prime_bug_LDADD = ../ginac/libginac.la
AM_CPPFLAGS = -I$(srcdir)/../ginac -I../ginac -DIN_GINAC
--- /dev/null
+/** @file pgcd_relatively_prime_bug.cpp
+ *
+ * A program exposing historical bug in the pgcd() function.
+ */
+#include <string>
+#include <iostream>
+#include <utility>
+#include "ginac.h"
+using namespace std;
+using namespace GiNaC;
+
+int main(int argc, char** argv)
+{
+ cout << "Checking for pgcd() bug regarding relatively prime polynomials: " << flush;
+ const symbol q("q");
+ parser reader;
+ reader.get_syms().insert(make_pair(string("q"), q));
+
+ ex t = reader("-E20^16*E4^8*E5^8*E1^16*q^4"
+ "-(E10^24-E20^8*E5^16)*E4^16*E1^8"
+ "+E2^24*E20^16*E5^8*q^4");
+ ex g = gcd(t.expand(), t.diff(q).expand()) - 1;
+ if (!g.is_zero()) {
+ cout << " oops!" << endl <<
+ "** Error: should be 0, got " << g << endl << flush;
+ throw std::logic_error("gcd was miscalculated");
+ }
+ cout << "not found" << endl << flush;
+ return 0;
+}
+
// evaluation point is bad. Skip it.
continue;
}
+ if (img_gcd_deg == 0)
+ return cont_gcd;
// Image has the same degree as the previous one
// (or at least not higher than the limit)
if (divide_in_z_p(Aprim, C, dummy1, vars, p) &&
divide_in_z_p(Bprim, C, dummy2, vars, p))
return (cont_gcd*C).expand().smod(pn);
- else if (img_gcd_deg == 0)
- return cont_gcd;
// else continue building the candidate
}
} while(true);