added new compile flag NOFIELD, which when defined compiles a version of wolff for use with zero field

2 files changed, 25 insertions, 8 deletions

diff --git a/lib/cluster.h b/lib/cluster.h
index 9dcf50d..f57bb68 100644
--- a/lib/cluster.h
+++ b/lib/cluster.h
@@ -25,24 +25,28 @@ void flip_cluster(state_t<R_t, X_t>& s, v_t v0, const R_t& r, gsl_rng *rand) {
     stack.pop();
 
     if (!marks[v]) { // don't reprocess anyone we've already visited!
+      marks[v] = true;
+
       X_t si_new;
+#ifndef NOFIELD
       R_t R_new;
 
-      marks[v] = true;
-
       bool v_is_ghost = (v == s.nv); // ghost site has the last index
 
       if (v_is_ghost) {
         R_new = r.act(s.R); // if we are, then we're moving the transformation
-      } else {
+      } else
+#endif
+      {
         si_new = r.act(s.spins[v]); // otherwise, we're moving the spin at our site
       }
 
       for (const v_t &vn : s.g.v_adj[v]) {
-        bool vn_is_ghost = (vn == s.nv); // any of our neighbors could be the ghost
-
         double dE, prob;
 
+#ifndef NOFIELD
+        bool vn_is_ghost = (vn == s.nv); // any of our neighbors could be the ghost
+
         if (v_is_ghost || vn_is_ghost) { // this is a ghost-involved bond
           X_t rs_old, rs_new;
           v_t non_ghost;
@@ -69,7 +73,9 @@ void flip_cluster(state_t<R_t, X_t>& s, v_t v0, const R_t& r, gsl_rng *rand) {
 
           s.update_magnetization(rs_old, rs_new);
           s.update_fourierZero(non_ghost, rs_old, rs_new);
-        } else { // this is a perfectly normal bond!
+        } else // this is a perfectly normal bond!
+#endif
+        {
           dE = s.J(s.spins[v], s.spins[vn]) - s.J(si_new, s.spins[vn]);
 
 #ifdef FINITE_STATES
@@ -88,9 +94,12 @@ void flip_cluster(state_t<R_t, X_t>& s, v_t v0, const R_t& r, gsl_rng *rand) {
         }
       }
 
+#ifndef NOFIELD
       if (v_is_ghost) {
         s.R = R_new;
-      } else {
+      } else
+#endif
+      {
         s.spins[v] = si_new;
         nv++;
       }
diff --git a/lib/state.h b/lib/state.h
index 3bbed39..cad453c 100644
--- a/lib/state.h
+++ b/lib/state.h
@@ -29,14 +29,22 @@ class state_t {
     std::vector<typename X_t::F_t> ImF;
 
     std::function <double(const X_t&, const X_t&)> J;
+#ifndef NOFIELD
     std::function <double(const X_t&)> H;
 
     state_t(D_t D, L_t L, double T, std::function <double(const X_t&, const X_t&)> J, std::function <double(const X_t&)> H) : D(D), L(L), g(D, L), T(T), R(), J(J), H(H) {
+#else
+    state_t(D_t D, L_t L, double T, std::function <double(const X_t&, const X_t&)> J) : D(D), L(L), g(D, L), T(T), R(), J(J) {
+#endif
       nv = g.nv;
       ne = g.ne;
-      g.add_ext();
       spins.resize(nv);
+#ifndef NOFIELD
+      g.add_ext();
       E = - (double)ne * J(spins[0], spins[0]) - (double)nv * H(spins[0]);
+#else
+      E = - (double)ne * J(spins[0], spins[0]);
+#endif
       M = spins[0] * nv;
       last_cluster_size = 0;
       ReF.resize(D);