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[ginac.git] / ginac / normal.h

diff --git a/ginac/normal.h b/ginac/normal.h
index 5a735e346a8f485bfeaf1811ba329951b90c39c9..eb579d6b4cb5aa3ebf181b02cd9f56e0269c0387 100644 (file)
--- a/ginac/normal.h
+++ b/ginac/normal.h
@@ -6,7 +6,7 @@
  *  computation, square-free factorization and rational function normalization. */
 
 /*
- *  GiNaC Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2019 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -23,22 +23,26 @@
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
-#ifndef __GINAC_NORMAL_H__
-#define __GINAC_NORMAL_H__
+#ifndef GINAC_NORMAL_H
+#define GINAC_NORMAL_H
 
 #include "lst.h"
 
 namespace GiNaC {
 
 /**
- * Flags to control the behaviour of gcd() and friends
+ * Flags to control the behavior of gcd() and friends
  */
 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
+
        };
 };
 
@@ -74,8 +85,8 @@ extern ex sprem(const ex &a, const ex &b, const ex &x, bool check_args = true);
 extern bool divide(const ex &a, const ex &b, ex &q, bool check_args = true);
 
 // Polynomial GCD in Z[X], cofactors are returned in ca and cb, if desired
-extern ex gcd(const ex &a, const ex &b, ex *ca = NULL, ex *cb = NULL,
-             bool check_args = true, unsigned options = 0);
+extern ex gcd(const ex &a, const ex &b, ex *ca = nullptr, ex *cb = nullptr,
+              bool check_args = true, unsigned options = 0);
 
 // Polynomial LCM in Z[X]
 extern ex lcm(const ex &a, const ex &b, bool check_args = true);
@@ -94,4 +105,4 @@ extern ex resultant(const ex & e1, const ex & e2, const ex & s);
 
 } // namespace GiNaC
 
-#endif // ndef __GINAC_NORMAL_H__
+#endif // ndef GINAC_NORMAL_H