File: shift_left.c

package info (click to toggle)
flint 2.5.2-19
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 30,308 kB
  • sloc: ansic: 289,367; cpp: 11,210; python: 1,280; sh: 649; makefile: 283
file content (71 lines) | stat: -rw-r--r-- 2,060 bytes parent folder | download | duplicates (4)
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
/*=============================================================================

    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 <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"

void
_fmpz_poly_shift_left(fmpz * res, const fmpz * poly, slong len, slong n)
{
    slong i;

    /* Copy in reverse to avoid writing over unshifted coefficients */
    if (res != poly)
    {
        for (i = len; i--; )
            fmpz_set(res + n + i, poly + i);
    }
    else
    {
        for (i = len; i--; )
            fmpz_swap(res + n + i, res + i);
    }

    for (i = 0; i < n; i++)
        fmpz_zero(res + i);
}

void
fmpz_poly_shift_left(fmpz_poly_t res, const fmpz_poly_t poly, slong n)
{
    if (n == 0)
    {
        fmpz_poly_set(res, poly);
        return;
    }

    if (poly->length == 0)
    {
        fmpz_poly_zero(res);
        return;
    }

    fmpz_poly_fit_length(res, poly->length + n);
    _fmpz_poly_shift_left(res->coeffs, poly->coeffs, poly->length, n);
    _fmpz_poly_set_length(res, poly->length + n);
}