pgcd(), chinrem_gcd(): use appropriate definition of the degree.

[ginac.git] / ginac / polynomial / pgcd.cpp

diff --git a/ginac/polynomial/pgcd.cpp b/ginac/polynomial/pgcd.cpp
index 0de0f70e5e0606e645f48b48d530d90c01700fea..a33b02d78a7dfc2fdb9fc20818b9c30271c52fb2 100644 (file)
--- a/ginac/polynomial/pgcd.cpp
+++ b/ginac/polynomial/pgcd.cpp
@@ -80,7 +80,8 @@ ex pgcd(const ex& A, const ex& B, const exvector& vars, const long p)
        const ex lc_gcd = euclid_gcd(AL, BL, mainvar, p);
 
        // The estimate of degree of the gcd of Ab and Bb
-       int gcd_deg = std::min(degree(Aprim, mainvar), degree(Bprim, mainvar));
+       exp_vector_t gcd_deg = std::min(degree_vector(Aprim, restvars),
+                                       degree_vector(Bprim, restvars));
        eval_point_finder::value_type b;
 
        eval_point_finder find_eval_point(p);
@@ -105,8 +106,11 @@ ex pgcd(const ex& A, const ex& B, const exvector& vars, const long p)
                const cln::cl_I correct_lc = smod(lcb_gcd*recip(Cblc, p), p);
                Cb = (Cb*numeric(correct_lc)).smod(pn);
 
+               const exp_vector_t img_gcd_deg = degree_vector(Cb, restvars);
+               // Test for relatively prime polynomials
+               if (zerop(img_gcd_deg))
+                       return cont_gcd;
                // Test for unlucky homomorphisms
-               const int img_gcd_deg = Cb.degree(restvars.back());
                if (img_gcd_deg < gcd_deg) {
                        // The degree decreased, previous homomorphisms were
                        // bad, so we have to start it all over.
@@ -121,8 +125,6 @@ ex pgcd(const ex& A, const ex& B, const exvector& vars, const long p)
                        // 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)
@@ -134,8 +136,6 @@ ex pgcd(const ex& A, const ex& B, const exvector& vars, const long p)
                const ex H_lcoeff = lcoeff_wrt(H, restvars);
 
                if (H_lcoeff.is_equal(lc_gcd)) {
-                       if ((Hprev-H).expand().smod(pn).is_zero())
-                               continue;
                        ex C /* primitive part of H */, contH /* dummy */;
                        primpart_content(C, contH, H, vars, p);
                        // Normalize GCD so that leading coefficient is 1