From 2af9351db3aa97da9b0d3f23d53a593bc96c8a8e Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Fri, 2 Feb 2018 18:33:22 -0500
Subject: does potts now, no external libraries

---
 lib/graph.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 lib/graph.c

(limited to 'lib/graph.c')

diff --git a/lib/graph.c b/lib/graph.c
new file mode 100644
index 0000000..a1edf13
--- /dev/null
+++ b/lib/graph.c
@@ -0,0 +1,67 @@
+
+#include "graph.h"
+
+graph_t *graph_create_square(D_t D, L_t L) {
+  v_t nv = pow(L, D);
+  v_t ne = D * nv;
+
+  v_t *v_i = (v_t *)malloc((nv + 1) * sizeof(v_t));
+
+  for (v_t i = 0; i < nv + 1; i++) {
+    v_i[i] = 2 * D * i;
+  }
+
+  v_t *v_adj = (v_t *)malloc(2 * D * nv * sizeof(v_t));
+
+  for (v_t i = 0; i < nv; i++) {
+    for (D_t j = 0; j < D; j++) {
+      v_adj[v_i[i] + 2 * j] = pow(L, j + 1) * (i / ((v_t)pow(L, j + 1))) + fmod(i + pow(L, j), pow(L, j + 1));
+      v_adj[v_i[i] + 2 * j + 1] = pow(L, j + 1) * (i / ((v_t)pow(L, j + 1))) + fmod(pow(L, j+1) + i - pow(L, j), pow(L, j + 1));
+    }
+  }
+
+  graph_t *g = (graph_t *)malloc(sizeof(graph_t));
+
+  g->ne = ne;
+  g->nv = nv;
+  g->v_i = v_i;
+  g->v_adj = v_adj;
+
+  return g;
+}
+
+graph_t *graph_add_ext(const graph_t *G) {
+  graph_t *tG = (graph_t *)calloc(1, sizeof(graph_t));
+
+  tG->nv = G->nv + 1;
+  tG->ne = G->ne + G->nv;
+
+  tG->v_i = (v_t *)malloc((tG->nv + 1) * sizeof(v_t));
+  tG->v_adj = (v_t *)malloc(2 * tG->ne * sizeof(v_t));
+
+  for (v_t i = 0; i < G->nv + 1; i++) {
+    tG->v_i[i] = G->v_i[i] + i;
+  }
+
+  tG->v_i[tG->nv] = 2 * tG->ne;
+
+  for (v_t i = 0; i < G->nv; i++) {
+    v_t nn = G->v_i[i + 1] - G->v_i[i];
+
+    for (v_t j = 0; j < nn; j++) {
+      tG->v_adj[tG->v_i[i] + j] = G->v_adj[G->v_i[i] + j];
+    }
+
+    tG->v_adj[tG->v_i[i] + nn] = G->nv;
+    tG->v_adj[tG->v_i[G->nv] + i] = i;
+  }
+
+  return tG;
+}
+
+void graph_free(graph_t *g) {
+  free(g->v_i);
+  free(g->v_adj);
+  free(g);
+}
+
-- 
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