模板 - 基于 std::valarray 实现的矩阵
基于 C++17 标准,实现了矩阵的运算,求逆,转置,秩,行列式,Gauss 消元,支持流式 IO
仅在 GCC 下测试过
使用说明
- 元素类型
Tp
须有接受 1 个整数的构造函数,Tp{0}
需为零元,Tp{1}
需为幺元 - Gauss-Jordan 消元法有普通版,辗转相除版与异或版,其中普通版推荐用于浮点数,辗转相除版推荐用于整数,异或版推荐用于
bool
, 这三种实现分别位于Matrix::matrix
,Matrix::matrix_int
,Matrix::matrix_bool
中
成员函数 & 友元函数列表
1 | template <class Tp, class Iszero_t = std::function<bool(Tp)>> |
代码
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1 | namespace Matrix { |
示例
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1 |
|
洛谷 P2447 [SDOI2010] 外星千足虫
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Luogu_P2447view raw 1
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329/*
* @Author: Tifa
* @Description: From <https://github.com/Tiphereth-A/CP-archives>
* !!! ATTENEION: All the context below is licensed under a
* GNU Affero General Public License, Version 3.
* See <https://www.gnu.org/licenses/agpl-3.0.txt>.
*/
using namespace std;
template <class Tp, class Iszero_t = std::function<bool(Tp)>>
class matrix {
using self = matrix<Tp, Iszero_t>;
protected:
constexpr bool
gauss_swapr__(size_t &row_, size_t row_pre_, size_t col_, size_t row_end) {
row_ = row_pre_;
for (size_t j = row_ + 1; j < row_end; ++j)
if (std::abs((*this)(j, col_)) > std::abs((*this)(row_, col_))) row_ = j;
if (row_ != row_pre_) {
swap_row(row_, row_pre_);
return true;
}
return false;
}
protected:
size_t r_sz, c_sz;
Iszero_t iszero;
std::valarray<Tp> data;
public:
matrix(size_t row, size_t col, Iszero_t iszero_func, const Tp &val = Tp{})
: r_sz(row), c_sz(col), iszero(iszero_func), data(val, row * col) {
ASSERT_(row > 0 && col > 0);
}
matrix(size_t row,
size_t col,
Iszero_t iszero_func,
const std::valarray<Tp> &data_)
: r_sz(row), c_sz(col), iszero(iszero_func), data(data_) {
ASSERT_(row > 0 && col > 0);
}
constexpr size_t row_size() const { return r_sz; }
constexpr size_t col_size() const { return c_sz; }
std::valarray<Tp> view() const { return data; }
Tp &operator()(size_t r, size_t c) { return data[r * col_size() + c]; }
Tp operator()(size_t r, size_t c) const { return data[r * col_size() + c]; }
friend std::istream &operator>>(std::istream &is, self &mat) {
for (auto &i : mat.data) is >> i;
return is;
}
friend std::ostream &operator<<(std::ostream &os, const self &mat) {
for (size_t i = 0; i < mat.row_size(); ++i)
for (size_t j = 0; j < mat.col_size(); ++j)
os << mat(i, j) << " \n"[j == mat.col_size() - 1];
return os;
}
INVOKES_SLICE__(row, size_t, r, {
return data[std::slice(r * col_size(), col_size(), 1)];
})
INVOKES_SLICE__(col, size_t, c, {
return data[std::slice(c, row_size(), col_size())];
})
INVOKES_SLICE__(diag_cycle, ptrdiff_t, d, {
return data[d >= 0 ?
std::slice(d, row_size(), col_size() + 1) :
std::slice(-d * row_size(), row_size(), col_size() + 1)];
})
self submatrix(size_t row_l, size_t row_r, size_t col_l, size_t col_r) const {
return self(row_r - row_l,
col_r - col_l,
data[std::gslice(row_l * col_size() + col_l,
{row_r - row_l, col_r - col_l},
{col_size(), 1})],
iszero);
}
std::gslice_array<Tp>
submatrix_raw(size_t row_l, size_t row_r, size_t col_l, size_t col_r) {
return data[std::gslice(row_l * col_size() + col_l,
{row_r - row_l, col_r - col_l},
{col_size(), 1})];
}
OPB__(==)
OPB__(!=)
OPB__(<)
OPB__(<=)
OPB__(>)
OPB__(>=)
OP__(+)
OP__(-)
OP__(%)
OP__(&)
OP__(^)
OP__(<<)
OP__(>>)
OPF__(*, {
ASSERT_(lhs.col_size() == rhs.row_size());
self ret(lhs.row_size(), rhs.col_size(), lhs.iszero, Tp{});
for (size_t i = 0; i < ret.row_size(); ++i) {
auto &&r_ = lhs.row(i);
for (size_t j = 0; j < ret.col_size(); ++j)
ret(i, j) = (r_ * rhs.col(j)).sum();
}
return ret;
})
OPF__(/, { return lhs * rhs.inverse(); })
OPF__(|, {
ASSERT_(lhs.row_size() == lhs.col_size() &&
rhs.row_size() == lhs.row_size());
self tmp_ = merge_lr(lhs, rhs);
ASSERTT_(std::abs(tmp_.do_gauss()) == lhs.row_size(), "Inverse not exist");
for (size_t i = 0; i < lhs.row_size(); ++i)
tmp_
.data[std::slice(i * (lhs.col_size() + rhs.col_size()) + lhs.col_size(),
rhs.col_size(),
1)] /= std::valarray<Tp>(tmp_(i, i), rhs.col_size());
return tmp_.submatrix(
0, rhs.row_size(), lhs.col_size(), lhs.col_size() + rhs.col_size());
})
friend self merge_ud(const self &lhs, const self &rhs) {
ASSERT_(lhs.col_size() == rhs.col_size());
self ret(lhs.row_size() + rhs.row_size(), lhs.col_size(), Tp{}, lhs.iszero);
ret.data[std::slice(0, lhs.row_size() * lhs.col_size(), 1)] = lhs.view();
ret.data[std::slice(
lhs.row_size() * lhs.col_size(), rhs.row_size() * rhs.col_size(), 1)] =
rhs.view();
return ret;
}
friend self merge_lr(const self &lhs, const self &rhs) {
ASSERT_(lhs.row_size() == rhs.row_size());
self ret(lhs.row_size(), lhs.col_size() + rhs.col_size(), Tp{}, lhs.iszero);
ret.data[std::gslice(
0, {lhs.row_size(), lhs.col_size()}, {ret.col_size(), 1})] = lhs.view();
ret.data[std::gslice(
lhs.col_size(), {rhs.row_size(), rhs.col_size()}, {ret.col_size(), 1})] =
rhs.view();
return ret;
}
constexpr void swap_row(size_t r1, size_t r2) {
std::valarray<Tp> __ = row(r1);
row(r1) = row(r2);
row(r2) = __;
}
constexpr void swap_col(size_t c1, size_t c2) {
std::valarray<Tp> __ = col(c1);
col(c1) = col(c2);
col(c2) = __;
}
constexpr void swap_diag_cycle(size_t d1, size_t d2) {
std::valarray<Tp> __ = diag_cycle(d1);
diag_cycle(d1) = diag_cycle(d2);
diag_cycle(d2) = __;
}
virtual ptrdiff_t
do_gauss_range(size_t row_start, size_t row_end, bool clear_all = true) {
assert(row_start < row_end && row_end <= row_size());
size_t rk = 0;
bool neg = false;
for (size_t i = row_start, now_row; i < std::min(row_end, col_size());
++i) {
neg ^= gauss_swapr__(now_row, rk, i, row_end);
if (iszero((*this)(rk, i))) continue;
std::valarray<Tp> tmp_ =
data[std::slice(rk * col_size() + i + 1, col_size() - i - 1, 1)];
for (size_t j = clear_all ? 0 : rk + 1; j < row_end; ++j) {
if (j == rk || iszero((*this)(j, i))) continue;
Tp &&_ = (*this)(j, i) / (*this)(rk, i);
(*this)(j, i) = 0;
data[std::slice(j * col_size() + i + 1, col_size() - i - 1, 1)] -=
tmp_ * _;
}
++rk;
}
return neg ? -ptrdiff_t(rk) : ptrdiff_t(rk);
}
ptrdiff_t do_gauss(bool clear_all = true) {
return do_gauss_range(0, std::min(row_size(), col_size()), clear_all);
}
self transpose() const {
self ret(col_size(), row_size(), iszero, Tp{});
for (size_t i = 0; i < row_size(); ++i) ret.col(i) = row(i);
return ret;
}
self inverse() const {
ASSERT_(row_size() == col_size());
self ret(row_size(), col_size(), iszero, Tp{});
ret.diag_cycle(0) = 1;
ASSERTT_(std::abs((ret = merge_lr(*this, ret)).do_gauss()) == row_size(),
"Inverse not exist");
for (size_t i = 0; i < row_size(); ++i)
ret.data[std::slice((i * 2 + 1) * col_size(), col_size(), 1)] /=
std::valarray<Tp>(ret(i, i), col_size());
ret = ret.submatrix(0, row_size(), col_size(), col_size() * 2);
return ret;
}
Tp trace() const { return diag_cycle(0).sum(); }
size_t rank() const { return std::abs(self(*this).do_gauss(false)); }
Tp det() const {
ASSERT_(row_size() == col_size());
self tmp_(*this);
ptrdiff_t rk_ = tmp_.do_gauss(false);
if (std::abs(rk_) != row_size()) return Tp{};
Tp ret = tmp_(0, 0);
for (size_t i = 1; i < row_size(); ++i) ret *= tmp_(i, i);
return rk_ < 0 ? -ret : ret;
}
friend self pow(self mat, size_t b) {
self res(mat.row_size(), mat.col_size(), mat.iszero, Tp{});
res.diag_cycle(0) = 1;
for (; b; b >>= 1, mat *= mat)
if (b & 1) res *= mat;
return res;
}
};
class matrix_bool: public matrix<bool> {
using self = matrix_bool;
using base = matrix<bool>;
private:
constexpr static auto isz__ = [](bool x) { return !x; };
public:
matrix_bool(size_t row, size_t col, bool val = false)
: base(row, col, isz__, val) {}
matrix_bool(size_t row, size_t col, const std::valarray<bool> &data_)
: base(row, col, isz__, data_) {}
ptrdiff_t do_gauss_range(size_t row_start,
size_t row_end,
bool clear_all = true) override {
assert(row_start < row_end && row_end <= row_size());
size_t rk = 0;
bool neg = false;
for (size_t i = row_start, now_row; i < std::min(row_end, col_size());
++i) {
neg ^= gauss_swapr__(now_row, rk, i, row_end);
if (iszero((*this)(rk, i))) continue;
std::valarray<bool> tmp_ =
data[std::slice(rk * col_size() + i + 1, col_size() - i - 1, 1)];
for (size_t j = clear_all ? 0 : rk + 1; j < row_end; ++j) {
if (j == rk || iszero((*this)(j, i))) continue;
(*this)(j, i) = false;
data[std::slice(j * col_size() + i + 1, col_size() - i - 1, 1)] ^= tmp_;
}
++rk;
}
return neg ? -ptrdiff_t(rk) : ptrdiff_t(rk);
}
};
auto solve([[maybe_unused]] int t_ = 0) -> void {
int n, m;
cin >> n >> m;
matrix_bool mat(m, n + 1);
string s;
for (int i = 0, x; i < m; ++i) {
cin >> s >> x;
for (int j = 0; j < n; ++j) mat(i, j) = s[j] & 1;
mat(i, n) = x;
}
int cnt = n, last_rk = 0;
while ((last_rk = abs(mat.do_gauss_range(0, n))) != n) {
for (int i = last_rk; i < n; ++i) {
if (cnt >= m) {
cout << "Cannot Determine\n";
return;
}
mat.swap_row(i, cnt++);
if (cnt >= m) {
cout << "Cannot Determine\n";
return;
}
}
}
cout << cnt << '\n';
for (int i = 0; i < n; ++i) cout << (mat(i, n) ? "?y7M#" : "Earth") << '\n';
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int i_ = 0;
solve(i_);
return 0;
}