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#pragma once
#include <functional>
#include <assert.h>
#include <fftw3.h>
#include <float.h>
#include <gsl/gsl_randist.h>
#include <gsl/gsl_rng.h>
#include <inttypes.h>
#include <cmath>
#include <stdbool.h>
#include <string.h>
#include <sys/types.h>
#include "types.h"
#include "rand.h"
#include "stack.h"
#include "convex.h"
#include "graph.h"
#include "tree.h"
#include "measurement.h"
#include "vector.h"
#include "orthogonal.h"
#include "dihedral.h"
#include "dihinf.h"
#include "yule_walker.h"
template <class T>
void init(T*);
template <class T>
T scalar_multiple(v_t a, T b);
template <class R_t, class X_t>
X_t act(R_t a, X_t b);
template <class R_t, class X_t>
X_t act_inverse(R_t a, X_t b);
template <class T>
T copy(T a);
template <class T>
void free_spin(T a);
template <class T>
T add(T, T);
template <class T>
T subtract(T, T);
template <class T>
T gen_rot(gsl_rng *r);
template <class R_t, class X_t>
class state_t {
public:
D_t D;
L_t L;
v_t nv;
v_t ne;
graph_t *g;
double T;
X_t *spins;
R_t R;
double E;
X_t M; // the "sum" of the spins, like the total magnetization
std::function <double(X_t, X_t)> J;
std::function <double(X_t)> H;
state_t(D_t D, L_t L, double T, std::function <double(X_t, X_t)> J, std::function <double(X_t)> H) : D(D), L(L), T(T), J(J), H(H) {
graph_t *h = graph_create_square(D, L);
nv = h->nv;
ne = h->ne;
g = graph_add_ext(h);
graph_free(h);
spins = (X_t *)malloc(nv * sizeof(X_t));
for (v_t i = 0; i < nv; i++) {
init (&(spins[i]));
}
init (&R);
E = - (double)ne * J(spins[0], spins[0]) - (double)nv * H(spins[0]);
M = scalar_multiple (nv, spins[0]);
}
~state_t() {
graph_free(g);
for (v_t i = 0; i < nv; i++) {
free_spin(spins[i]);
}
free(spins);
free_spin(R);
free_spin(M);
}
};
template <class R_t, class X_t>
v_t flip_cluster(state_t <R_t, X_t> *state, v_t v0, R_t r, gsl_rng *rand) {
v_t nv = 0;
ll_t *stack = NULL; // create a new stack
stack_push(&stack, v0); // push the initial vertex to the stack
bool *marks = (bool *)calloc(state->g->nv, sizeof(bool));
while (stack != NULL) {
v_t v = stack_pop(&stack);
if (!marks[v]) {
X_t si_old, si_new;
R_t R_old, R_new;
si_old = state->spins[v];
R_old = state->R;
marks[v] = true;
if (v == state->g->nv - 1) {
R_new = act (r, R_old);
} else {
si_new = act (r, si_old);
}
v_t nn = state->g->v_i[v + 1] - state->g->v_i[v];
for (v_t i = 0; i < nn; i++) {
v_t vn = state->g->v_adj[state->g->v_i[v] + i];
X_t sj;
if (vn != state->g->nv - 1) {
sj = state->spins[vn];
}
double prob;
bool is_ext = (v == state->g->nv - 1 || vn == state->g->nv - 1);
if (is_ext) {
X_t rs_old, rs_new;
if (vn == state->g->nv - 1) {
rs_old = act_inverse (R_old, si_old);
rs_new = act_inverse (R_old, si_new);
} else {
rs_old = act_inverse (R_old, sj);
rs_new = act_inverse (R_new, sj);
}
double dE = state->H(rs_old) - state->H(rs_new);
prob = 1.0 - exp(-dE / state->T);
subtract (state->M, rs_old);
add (state->M, rs_new);
state->E += dE;
free_spin (rs_old);
free_spin (rs_new);
} else {
double dE = state->J(si_old, sj) - state->J(si_new, sj);
prob = 1.0 - exp(-dE / state->T);
state->E += dE;
}
if (gsl_rng_uniform(rand) < prob) { // and with probability...
stack_push(&stack, vn); // push the neighboring vertex to the stack
}
}
if (v == state->g->nv - 1) {
free_spin(state->R);
state->R = R_new;
} else {
free_spin(state->spins[v]);
state->spins[v] = si_new;
}
if (v != state->g->nv - 1) { // count the number of non-external sites that flip
nv++;
}
}
}
free(marks);
return nv;
}
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