1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
/*=============================================================================
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) 2008, 2009 William Hart
Copyright (C) 2010 Sebastian Pancratz
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_vec.h"
#include "fmpz_poly.h"
void
_fmpz_poly_div_basecase(fmpz * Q, fmpz * R, const fmpz * A, slong lenA,
const fmpz * B, slong lenB)
{
const fmpz * leadB = B + lenB - 1;
slong B1, iQ = lenA - lenB;
slong alloc;
while (lenA >= lenB && fmpz_cmpabs(A + lenA - 1, leadB) < 0)
{
fmpz_zero(Q + iQ);
iQ--;
lenA--;
}
if (lenA < lenB)
return;
alloc = (R == NULL) ? lenA : 0;
if (alloc)
R = _fmpz_vec_init(alloc);
if (R != A)
_fmpz_vec_set(R + lenB - 1, A + lenB - 1, lenA - lenB + 1);
B1 = lenB - 1;
while (lenA >= lenB)
{
if (fmpz_cmpabs(R + lenA - 1, leadB) < 0)
fmpz_zero(Q + iQ);
else
{
fmpz_fdiv_q(Q + iQ, R + lenA - 1, leadB);
_fmpz_vec_scalar_submul_fmpz(R + lenA - B1 - 1, B, B1, Q + iQ);
}
if (B1 >= lenA - lenB + 1)
{
B++;
B1--;
}
lenA--;
iQ--;
}
if (alloc)
_fmpz_vec_clear(R, alloc);
}
void
fmpz_poly_div_basecase(fmpz_poly_t Q,
const fmpz_poly_t A, const fmpz_poly_t B)
{
slong lenq;
fmpz *q;
if (B->length == 0)
{
flint_printf("Exception (fmpz_poly_div_basecase). Division by zero.\n");
abort();
}
if (A->length < B->length)
{
fmpz_poly_zero(Q);
return;
}
lenq = A->length - B->length + 1;
if ((Q == A) || (Q == B))
q = _fmpz_vec_init(lenq);
else
{
fmpz_poly_fit_length(Q, lenq);
q = Q->coeffs;
}
_fmpz_poly_div_basecase(q, NULL, A->coeffs, A->length,
B->coeffs, B->length);
if ((Q == A) || (Q == B))
{
_fmpz_vec_clear(Q->coeffs, Q->alloc);
Q->coeffs = q;
Q->alloc = lenq;
Q->length = lenq;
}
else
_fmpz_poly_set_length(Q, lenq);
_fmpz_poly_normalise(Q);
}
|
