Implement modular multivariate GCD (based on chinese remaindering algorithm).

[ginac.git] / ginac / normal.h

diff --git a/ginac/normal.h b/ginac/normal.h
index 5a735e346a8f485bfeaf1811ba329951b90c39c9..a352be8c8ef5f7fd5da48f8c6a95362db1667f26 100644 (file)
--- a/ginac/normal.h
+++ b/ginac/normal.h
@@ -37,8 +37,12 @@ struct gcd_options
 {
        enum {
                /**
-                * Usually GiNaC tries heuristic GCD algorithm before PRS.
-                * Some people don't like this, so here's a flag to disable it.
+                * Usually GiNaC tries heuristic GCD first, because typically
+                * it's much faster than anything else. Even if heuristic
+                * algorithm fails, the overhead is negligible w.r.t. cost
+                * of computing the GCD by some other method. However, some
+                * people dislike it, so here's a flag which tells GiNaC
+                * to NOT use the heuristic algorithm.
                 */
                no_heur_gcd = 2,
                /**
@@ -48,7 +52,14 @@ struct gcd_options
                 * factored polynomials. DON'T SET THIS unless you *really*
                 * know what are you doing!
                 */
-               no_part_factored = 4
+               no_part_factored = 4,
+               /**
+                * By default GiNaC uses modular GCD algorithm. Typically
+                * it's much faster than PRS (pseudo remainder sequence)
+                * algorithm. This flag forces GiNaC to use PRS algorithm
+                */
+               use_sr_gcd = 8
+
        };
 };