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
/*
Copyright (C) 2017 Daniel Schultz
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "mpoly.h"
void mpoly_get_cmpmask(ulong * cmpmask, slong N, flint_bitcnt_t bits,
const mpoly_ctx_t mctx)
{
slong i;
if (mctx->rev)
{
/* DEGREVLEX has a bit set everywhere except the in most significant field */
if (bits <= FLINT_BITS)
{
for (i = 0; i + 1 < N; i++)
cmpmask[i] = -UWORD(1);
cmpmask[N - 1] = (UWORD(1) << (mctx->nvars%(FLINT_BITS/bits)*bits)) - UWORD(1);
}
else
{
for (i = 0; i < N - (slong) bits/FLINT_BITS; i++)
cmpmask[i] = -UWORD(1);
for (; i < N; i++)
cmpmask[i] = UWORD(0);
}
}
else
{
/* LEX and DEGLEX use a clear mask */
for (i = 0; i < N; i++)
cmpmask[i] = UWORD(0);
}
}