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template <typename T>
T determinant(vector<vector<T> > a) {
int n = a.size();
REP (z, n) { // make A upper trianglar
if (a[z][z] == 0) { // swap rows to avoid zero-division
int x = z + 1;
for (; x < n; ++ x) {
if (a[x][z] != 0) {
a[z].swap(a[x]);
break;
}
}
if (x == n) return 0; // A is singular
}
REP3 (y, z + 1, n) {
T k = a[y][z] / a[z][z];
REP3 (x, z + 1, n) {
a[y][x] -= k * a[z][x]; // elim
}
a[y][z] = 0;
}
}
T acc = 1;
REP (z, n) acc *= a[z][z]; // product of the diagonal elems
return acc;
}
template <class T>
vector<vector<T> > small_matrix(vector<vector<T> > const & a) {
int n = a.size();
assert (n >= 1);
auto b = a;
b.resize(n - 1);
REP (y, n - 1) {
b[y].resize(n - 1);
}
return b;
}
template <typename T>
vector<T> gaussian_elimination(vector<vector<T> > f, vector<T> x) {
int n = x.size();
REP (y, n) {
int pivot = y;
while (pivot < n and abs(f[pivot][y]) < eps) ++ pivot;
assert (pivot < n);
swap(f[y], f[pivot]);
x[y] /= f[y][y];
REP3 (x, y + 1, n) f[y][x] /= f[y][y];
f[y][y] = 1;
REP (ny, n) if (ny != y) {
x[ny] -= f[ny][y] * x[y];
REP3 (x, y + 1, n) f[ny][x] -= f[ny][y] * f[y][x];
f[ny][y] = 0;
}
}
return x;
}
constexpr double eps = 1e-8;
template <typename T>
vector<vector<T> > inverse_matrix(vector<vector<T> > f) {
int n = f.size();
vector<vector<T> > g = unit_matrix<T>(n);
REP (y, n) {
int pivot = y;
while (pivot < n and abs(f[pivot][y]) < eps) ++ pivot;
assert (pivot < n);
swap(f[y], f[pivot]);
REP (x, n) g[y][x] /= f[y][y];
REP3 (x, y + 1, n) f[y][x] /= f[y][y];
f[y][y] = 1;
REP (ny, n) if (ny != y) {
REP (x, n) g[ny][x] -= f[ny][y] * g[y][x];
REP3 (x, y + 1, n) f[ny][x] -= f[ny][y] * f[y][x];
f[ny][y] = 0;
}
}
return g;
}
unittest {
vector<vector<double> > f { { 1, 2 }, { 3, 4 } };
auto g = f * inverse_matrix(f);
assert (abs(g[0][0] - 1) < eps);
assert (abs(g[0][1] ) < eps);
assert (abs(g[1][0] ) < eps);
assert (abs(g[1][1] - 1) < eps);
}
template <typename T>
vector<vector<T> > concat_matrix_vector(vector<vector<T> > const & f, vector<T> const & x) {
int h = f.size();
int w = f.fornt().size();
vector<vector<T> > fx(h);
REP (y, h) {
fx[y].resize(w + 1);
copy(whole(f[y]), fx[y].begin());
fx[y][w] = x[y];
}
return fx;
}
#line 1 "old/matrix.inc.cpp"
template <typename T>
T determinant(vector<vector<T> > a) {
int n = a.size();
REP (z, n) { // make A upper trianglar
if (a[z][z] == 0) { // swap rows to avoid zero-division
int x = z + 1;
for (; x < n; ++ x) {
if (a[x][z] != 0) {
a[z].swap(a[x]);
break;
}
}
if (x == n) return 0; // A is singular
}
REP3 (y, z + 1, n) {
T k = a[y][z] / a[z][z];
REP3 (x, z + 1, n) {
a[y][x] -= k * a[z][x]; // elim
}
a[y][z] = 0;
}
}
T acc = 1;
REP (z, n) acc *= a[z][z]; // product of the diagonal elems
return acc;
}
template <class T>
vector<vector<T> > small_matrix(vector<vector<T> > const & a) {
int n = a.size();
assert (n >= 1);
auto b = a;
b.resize(n - 1);
REP (y, n - 1) {
b[y].resize(n - 1);
}
return b;
}
template <typename T>
vector<T> gaussian_elimination(vector<vector<T> > f, vector<T> x) {
int n = x.size();
REP (y, n) {
int pivot = y;
while (pivot < n and abs(f[pivot][y]) < eps) ++ pivot;
assert (pivot < n);
swap(f[y], f[pivot]);
x[y] /= f[y][y];
REP3 (x, y + 1, n) f[y][x] /= f[y][y];
f[y][y] = 1;
REP (ny, n) if (ny != y) {
x[ny] -= f[ny][y] * x[y];
REP3 (x, y + 1, n) f[ny][x] -= f[ny][y] * f[y][x];
f[ny][y] = 0;
}
}
return x;
}
constexpr double eps = 1e-8;
template <typename T>
vector<vector<T> > inverse_matrix(vector<vector<T> > f) {
int n = f.size();
vector<vector<T> > g = unit_matrix<T>(n);
REP (y, n) {
int pivot = y;
while (pivot < n and abs(f[pivot][y]) < eps) ++ pivot;
assert (pivot < n);
swap(f[y], f[pivot]);
REP (x, n) g[y][x] /= f[y][y];
REP3 (x, y + 1, n) f[y][x] /= f[y][y];
f[y][y] = 1;
REP (ny, n) if (ny != y) {
REP (x, n) g[ny][x] -= f[ny][y] * g[y][x];
REP3 (x, y + 1, n) f[ny][x] -= f[ny][y] * f[y][x];
f[ny][y] = 0;
}
}
return g;
}
unittest {
vector<vector<double> > f { { 1, 2 }, { 3, 4 } };
auto g = f * inverse_matrix(f);
assert (abs(g[0][0] - 1) < eps);
assert (abs(g[0][1] ) < eps);
assert (abs(g[1][0] ) < eps);
assert (abs(g[1][1] - 1) < eps);
}
template <typename T>
vector<vector<T> > concat_matrix_vector(vector<vector<T> > const & f, vector<T> const & x) {
int h = f.size();
int w = f.fornt().size();
vector<vector<T> > fx(h);
REP (y, h) {
fx[y].resize(w + 1);
copy(whole(f[y]), fx[y].begin());
fx[y][w] = x[y];
}
return fx;
}