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
|
/*======================================================================
SIGNP1(c,P1,I)
Signatures of Projection factors, $1$--level.
\Input
\parm{c} is the root cell.
\parm{P1} is the list of the $1$--level projection factors.
\parm{I} is a list of the real roots of $P_1$ (see CONSTRUCT).
\Output
The signatures of~$P_1$ on the cells
in the stack over the root cell~$c$
are determined and attached to them.
======================================================================*/
#include "qepcad.h"
#include <vector>
using namespace std;
void SIGNP1(Word c, Word P1, Word I)
{
Word c1,cb,I1;
Step1: /* Compute the signatures of $P_1$. */
vector<BDigit> S;
for(Word P = P1; P != NIL; P = RED(P)) {
Word p = FIRST(P);
if (LELTI(p,PO_TYPE) == PO_POINT || EVEN(PDEG(LELTI(p,PO_POLY))))
S.push_back(1);
else
S.push_back(-1); }
vector< vector<BDigit> > M;
M.push_back(S);
int i = 1;
while(I != NIL) {
M.push_back(M[i-1]);
M.push_back(M[i-1]);
i += 2;
ADV(I,&I1,&I);
for(Word L = THIRD(I1); L != NIL; L = RED(L)) {
Word a = FIRST(L);
BDigit j = 1;
for(Word T = P1; FIRST(T) != a; T = RED(T), j++);
M[i-2][j-1] = 0;
M[i-1][j-1] = -M[i-3][j-1]; }
}
Step2: /* Attach the signatures to the cells. */
int k = 0;
cb = LELTI(c,CHILD);
while (cb != NIL)
{
ADV(cb,&c1,&cb);
Word s = NIL; for(int i = S.size()-1; i >= 0; i--) s = COMP(M[k][i],s);
SFIRST(LELTI(c1,SIGNPF),s);
k++;
}
goto Return;
Return: /* Prepare for return. */
return;
}
|
