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
/*
Copyright (C) 2012, 2018 Fredrik Johansson
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 "arb.h"
#include "arb_mat.h"
void
arb_mat_mul_classical(arb_mat_t C, const arb_mat_t A, const arb_mat_t B, slong prec)
{
slong ar, ac, br, bc, i, j, k;
if (A == B && (arb_mat_nrows(A) <= 2 ||
(prec >= 1024 && arb_mat_nrows(A) < 8)))
{
arb_mat_sqr_classical(C, A, prec);
return;
}
ar = arb_mat_nrows(A);
ac = arb_mat_ncols(A);
br = arb_mat_nrows(B);
bc = arb_mat_ncols(B);
if (ac != br || ar != arb_mat_nrows(C) || bc != arb_mat_ncols(C))
{
flint_throw(FLINT_ERROR, "arb_mat_mul: incompatible dimensions\n");
}
if (br == 0)
{
arb_mat_zero(C);
return;
}
if (A == C || B == C)
{
arb_mat_t T;
arb_mat_init(T, ar, bc);
arb_mat_mul_classical(T, A, B, prec);
arb_mat_swap_entrywise(T, C);
arb_mat_clear(T);
return;
}
if (br <= 2)
{
for (i = 0; i < ar; i++)
{
for (j = 0; j < bc; j++)
{
/* todo: efficient fmma code */
arb_mul(arb_mat_entry(C, i, j),
arb_mat_entry(A, i, 0),
arb_mat_entry(B, 0, j), prec);
for (k = 1; k < br; k++)
{
arb_addmul(arb_mat_entry(C, i, j),
arb_mat_entry(A, i, k),
arb_mat_entry(B, k, j), prec);
}
}
}
}
else
{
for (i = 0; i < ar; i++)
for (j = 0; j < bc; j++)
arb_dot(arb_mat_entry(C, i, j), NULL, 0,
arb_mat_entry(A, i, 0), 1,
arb_mat_entry(B, 0, j), B->stride, br, prec);
}
}