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
126
127
128
129
130
131
132
133
134
135
136
137
|
// Copyright 2013 Michael E. Stillman
#ifndef __matrix_stream_hhp__
#define __matrix_stream_hhp__
#include "poly.hpp"
#include "matrix.hpp"
#include "matrix-con.hpp"
#if 0
// Example of the calls used to create an ideal (one rowed matrix), over a poly ring
// over a prime finite field.
// After this. s.value() returns the Matrix with these elements as columns.
s.idealBegin(2);
s.appendPolynomialBegin(2); // x^2 - y
s.appendTermBegin(0);
s.appendExponent(0,2);
s.appendTermDone(1);
s.appendTermBegin(0);
s.appendExponent(1,1);
s.appendTermDone(s.modulus() - 1);
s.appendPolynomialDone();
s.appendPolynomialBegin(2); // x^3-z
s.appendTermBegin(0);
s.appendExponent(0,3);
s.appendTermDone(1);
s.appendTermBegin(0);
s.appendExponent(2,1);
s.appendTermDone(s.modulus() - 1);
s.appendPolynomialDone();
s.idealDone();
#endif
class MatrixStream
{
public:
MatrixStream(const FreeModule* F);
~MatrixStream();
const PolyRing& ring() const { return *mPolyRing; }
const Matrix* value() const
{
return mValue;
} // This will return null before idealDone() is called.
// Fields required for the general stream interface (see mathicgb::mathicgb.h)
typedef int Coefficient;
// typedef long Coefficient;
typedef size_t VarIndex;
typedef int Exponent;
typedef unsigned int Component;
Coefficient modulus() const
{
return static_cast<int>(mPolyRing->characteristic());
}
VarIndex varCount() const { return mPolyRing->n_vars(); }
Component comCount() const { return mFreeModule->rank(); }
void idealBegin(size_t polyCount);
void appendPolynomialBegin(size_t termCount);
void appendTermBegin(Component com);
void appendExponent(VarIndex index, Exponent exponent);
void appendTermDone(Coefficient coefficient);
void appendPolynomialDone();
void idealDone();
private:
const PolyRing* mPolyRing;
const FreeModule* mFreeModule;
MatrixConstructor mMatrixConstructor;
const Matrix* mValue;
Exponent* mCurrentExponents;
Component mCurrentComponent;
Nterm** mCurrentColumn; // array 0..numcomps-1
Nterm** mLastTerms;
};
template <typename T>
void matrixToStream(const Matrix* M, T& stream)
{
const Ring* R = M->get_ring();
const PolyRing* P = R->cast_to_PolyRing();
assert(P != 0);
const Ring* KK = P->getCoefficientRing();
size_t nvars = P->n_vars();
size_t ncols = M->n_cols();
int charac = static_cast<int>(P->characteristic());
assert(charac > 0);
exponents exp =
ALLOCATE_EXPONENTS(EXPONENT_BYTE_SIZE(nvars)); // allocated on stack
stream.idealBegin(ncols);
Matrix::iterator i(M);
for (int c = 0; c < ncols; c++)
{
i.set(c);
// We need the length of this column, in number of monomials
size_t nterms = 0;
for (; i.valid(); i.next())
{
Nterm* t = i.entry();
for (Nterm* s = t; s != 0; s = s->next) nterms++;
}
stream.appendPolynomialBegin(nterms);
i.set(c);
// Now we process each column, sending it to the stream
for (; i.valid(); i.next())
{
Nterm* t = i.entry();
for (Nterm* s = t; s != 0; s = s->next)
{
P->getMonoid()->to_expvector(s->monom, exp);
stream.appendTermBegin(i.row());
for (size_t j = 0; j < nvars; j++)
if (exp[j] != 0) stream.appendExponent(j, exp[j]);
std::pair<bool, long> b = KK->coerceToLongInteger(s->coeff);
assert(b.first);
int a = static_cast<int>(
b.second); // This will fit, as the charac fits into an int
if (a < 0) a += charac;
stream.appendTermDone(a);
}
}
stream.appendPolynomialDone();
}
stream.idealDone();
}
#endif
// Local Variables:
// compile-command: "make -C $M2BUILDDIR/Macaulay2/e "
// indent-tabs-mode: nil
// End:
|
