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[ginac.git] / ginac / polynomial / remainder.h

diff --git a/ginac/polynomial/remainder.h b/ginac/polynomial/remainder.h
index 3b62ec4a485e470ab8bd57fa6447f3331562d04c..5e82149825a027bf6f3ea185e9ce51be11deb5e5 100644 (file)
--- a/ginac/polynomial/remainder.h
+++ b/ginac/polynomial/remainder.h
@@ -1,68 +1,36 @@
-#ifndef GINAC_UPOLY_REMAINDER_TCC
-#define GINAC_UPOLY_REMAINDER_TCC
-#include "upoly.h"
-#include "ring_traits.h"
-#include "upoly_io.h"
-#include "debug.h"
+/** @file remainder.h
+ *
+ *  Functions calculating remainders. */
 
-namespace GiNaC
-{
-/**
- * @brief Polynomial remainder for univariate polynomials over fields
+/*
+ *  GiNaC Copyright (C) 1999-2019 Johannes Gutenberg University Mainz, Germany
  *
- * Given two univariate polynomials \f$a, b \in F[x]\f$, where F is
- * a finite field (presumably Z/p) computes the remainder @a r, which is
- * defined as \f$a = b q + r\f$. Returns true if the remainder is zero
- * and false otherwise.
+ *  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
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
-static bool
-remainder_in_field(umodpoly& r, const umodpoly& a, const umodpoly& b)
-{
-       typedef cln::cl_MI field_t;
-
-       if (degree(a) < degree(b)) {
-               r = a;
-               return false;
-       }
-       // The coefficient ring is a field, so any 0 degree polynomial
-       // divides any other polynomial.
-       if (degree(b) == 0) {
-               r.clear();
-               return true;
-       }
-
-       r = a;
-       const field_t b_lcoeff = lcoeff(b);
-       for (std::size_t k = a.size(); k-- >= b.size(); ) {
-
-               // r -= r_k/b_n x^{k - n} b(x)
-               if (zerop(r[k]))
-                       continue;
 
-               field_t qk = div(r[k], b_lcoeff);
-               bug_on(zerop(qk), "division in a field yield zero: "
-                                  << r[k] << '/' << b_lcoeff);
+#ifndef GINAC_UPOLY_REMAINDER_H
+#define GINAC_UPOLY_REMAINDER_H
 
-               // Why C++ is so off-by-one prone?
-               for (std::size_t j = k, i = b.size(); i-- != 0; --j) {
-                       if (zerop(b[i]))
-                               continue;
-                       r[j] = r[j] - qk*b[i];
-               }
-               bug_on(!zerop(r[k]), "polynomial division in field failed: " <<
-                                     "r[" << k << "] = " << r[k] << ", " <<
-                                     "r = " << r << ", b = " << b);
+#include "upoly.h"
+#include "ring_traits.h"
+#include "upoly_io.h"
+#include "debug.h"
 
-       }
+namespace GiNaC {
 
-       // Canonicalize the remainder: remove leading zeros. Give a hint
-       // to canonicalize(): we know degree(remainder) < degree(b) 
-       // (because the coefficient ring is a field), so 
-       // c_{degree(b)} \ldots c_{degree(a)} are definitely zero.
-       std::size_t from = degree(b) - 1;
-       canonicalize(r, from);
-       return r.empty();
-}
+bool remainder_in_field(umodpoly& r, const umodpoly& a, const umodpoly& b);
 
 /**
  * @brief Polynomial remainder for univariate polynomials over a ring. 
@@ -110,7 +78,7 @@ bool remainder_in_ring(T& r, const T& a, const T& b)
        canonicalize(r);
        return r.empty();
 }
-} // namespace GiNaC
 
-#endif // GINAC_UPOLY_REMAINDER_TCC
+} // namespace GiNaC
 
+#endif // GINAC_UPOLY_REMAINDER_H