ALL: Add flint

external/flint-2.4.3/nmod_poly/compose_mod_horner.c

@@ -0,0 +1,133 @@
+/*=============================================================================
+
+    This file is part of FLINT.
+
+    FLINT 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.
+
+    FLINT 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 FLINT; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+
+=============================================================================*/
+/******************************************************************************
+
+   Copyright (C) 2011 Fredrik Johansson
+
+******************************************************************************/
+
+#include <gmp.h>
+#include "flint.h"
+#include "nmod_vec.h"
+#include "nmod_poly.h"
+#include "ulong_extras.h"
+
+void
+_nmod_poly_compose_mod_horner(mp_ptr res,
+    mp_srcptr f, slong lenf, mp_srcptr g, mp_srcptr h, slong lenh, nmod_t mod)
+{
+    slong i, len;
+    mp_ptr t;
+
+    if (lenh == 1)
+        return;
+
+    if (lenf == 1)
+    {
+        res[0] = f[0];
+        return;
+    }
+
+    if (lenh == 2)
+    {
+        res[0] = _nmod_poly_evaluate_nmod(f, lenf, g[0], mod);
+        return;
+    }
+
+    len = lenh - 1;
+    i = lenf - 1;
+    t = _nmod_vec_init(len);
+
+    _nmod_vec_scalar_mul_nmod(res, g, len, f[i], mod);
+    i--;
+    if (i >= 0)
+        res[0] = nmod_add(res[0], f[i], mod);
+
+    while (i > 0)
+    {
+        i--;
+        _nmod_poly_mulmod(t, res, len, g, len, h, lenh, mod);
+        _nmod_poly_add(res, t, len, f + i, 1, mod);
+    }
+
+    _nmod_vec_clear(t);
+}
+
+void
+nmod_poly_compose_mod_horner(nmod_poly_t res, 
+                    const nmod_poly_t poly1, const nmod_poly_t poly2,
+                    const nmod_poly_t poly3)
+{
+    slong len1 = poly1->length;
+    slong len2 = poly2->length;
+    slong len3 = poly3->length;
+    slong len = len3 - 1;
+
+    mp_ptr ptr2;
+
+    if (len3 == 0)
+    {
+        flint_printf("Exception (nmod_poly_compose_mod_horner). Division by zero.\n");
+        abort();
+    }
+
+    if (len1 == 0 || len3 == 1)
+    {
+        nmod_poly_zero(res);
+        return;
+    }
+
+    if (len1 == 1)
+    {
+        nmod_poly_set(res, poly1);
+        return;
+    }
+
+    if (res == poly3 || res == poly1)
+    {
+        nmod_poly_t tmp;
+        nmod_poly_init_preinv(tmp, res->mod.n, res->mod.ninv);
+        nmod_poly_compose_mod_horner(tmp, poly1, poly2, poly3);
+        nmod_poly_swap(tmp, res);
+        nmod_poly_clear(tmp);
+        return;
+    }
+
+    ptr2 = _nmod_vec_init(len);
+
+    if (len2 <= len)
+    {
+        flint_mpn_copyi(ptr2, poly2->coeffs, len2);
+        flint_mpn_zero(ptr2 + len2, len - len2);
+    }
+    else
+    {
+        _nmod_poly_rem(ptr2, poly2->coeffs, len2,
+                             poly3->coeffs, len3, res->mod);
+    }
+
+    nmod_poly_fit_length(res, len);
+    _nmod_poly_compose_mod_horner(res->coeffs,
+        poly1->coeffs, len1, ptr2, poly3->coeffs, len3, res->mod);
+    res->length = len;
+    _nmod_poly_normalise(res);
+
+    _nmod_vec_clear(ptr2);
+}