1 files changed, 135 insertions, 0 deletions
diff --git a/src/3rdparty/adaptagrams/libcola/tests/scale_free.cpp b/src/3rdparty/adaptagrams/libcola/tests/scale_free.cpp
new file mode 100644
index 0000000..d9c2934
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+++ b/src/3rdparty/adaptagrams/libcola/tests/scale_free.cpp
@@ -0,0 +1,135 @@
+/*
+ * vim: ts=4 sw=4 et tw=0 wm=0
+ *
+ * libcola - A library providing force-directed network layout using the 
+ *           stress-majorization method subject to separation constraints.
+ *
+ * Copyright (C) 2006-2008  Monash University
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library in the file LICENSE; if not, 
+ * write to the Free Software Foundation, Inc., 59 Temple Place, 
+ * Suite 330, Boston, MA  02111-1307  USA
+ *
+*/
+
+// generates a random graph with a power-law distribution of node degrees
+// the algorithm is pretty much the Barabasi-Albert model but with an extra step
+// so that I can guarantee the number of nodes in the graph.
+// We begin with an initial chain of m nodes.
+// Then, we add new nodes, connecting them to existing nodes v with probability
+// degree(v)/(sum all degrees)
+// We perform an extra step, looking for disconnected nodes, connecting them
+// to other nodes again with probability dependent on degree
+#include<iostream>
+#include<vector>
+#include <cmath>
+#include <time.h>
+#include <valarray>
+
+#include "graphlayouttest.h"
+
+void scale_free(const unsigned n = 50) {
+    const unsigned m = 3; // begin with a chain of m nodes
+    const double g=0.08; // edge density, every time we add a node we add 1+g*rand(0-1) edges
+                  // connecting them to existing nodes with probability based on degree
+    unsigned d[n];
+    double defaultEdgeLength=100;
+    vector<Edge> es;
+    CompoundConstraints cx,cy;
+    for(unsigned i=0;i<n;i++) {
+        d[i]=0;
+    }
+    unsigned sumdegree=0;
+    for(unsigned i=1;i<m;i++) {
+        es.push_back(make_pair(i-1,i)); 
+        d[i]++;d[i-1]++;
+        sumdegree+=2;
+    }
+    srand(3);
+    for(unsigned i=2;i<n;i++) {
+        for(unsigned j=0;j<i;j++) {
+            double p=(double)d[j]/(double)sumdegree;
+            double r=(double)rand()/(double)RAND_MAX;
+            if(r*p>g) {
+                es.push_back(make_pair(j,i)); 
+                d[j]++;d[i]++;
+                sumdegree+=2;
+            }
+        }
+    }
+    for(unsigned i=0;i<n;i++) {
+        if(d[i]==0) {
+            double maxP=0;
+            unsigned end=0;
+            for(unsigned j=0;j<n;j++) {
+                if(j==i) continue;
+                double p=(double)d[j]/(double)sumdegree;
+                double r=(double)rand()/(double)RAND_MAX;
+                if(r*p>maxP) {
+                    maxP=r*p;
+                    end=j;
+                }
+            }
+            if(end>i) {
+                es.push_back(make_pair(i,end)); 
+            } else {
+                es.push_back(make_pair(end,i)); 
+            }
+            d[end]++;d[i]++;
+            sumdegree+=2;
+        }
+    }
+    valarray<double> eweights(es.size());
+    sort(d,d+n);
+    unsigned degree=0,ctr=0;
+    printf("degree distribution:\n");
+    for(unsigned i=0;i<n;i++) {
+        if(degree!=d[i]) {
+            if(degree!=0) printf("%d,%d\n",degree,ctr);
+            degree=d[i]; 
+            ctr=0;
+        }
+        ctr++;
+    }
+    printf("%d,%d\n",degree,ctr);
+    for(unsigned i=0;i<es.size();i++) {
+        unsigned a=es[i].first, b=es[i].second;
+        eweights[i]=1;
+        cy.push_back(new SeparationConstraint(a,b,defaultEdgeLength/3));
+    }
+
+    cout << "|V|="<<n<<endl;
+    double width=1000;
+    double height=1000;
+    vector<pair<double,double> > startpos(n);
+    for(unsigned i=0;i<n;i++) {
+        double x=getRand(width), y=getRand(height);
+        startpos[i]=make_pair(x,y);
+    }
+    const char *f="scalefree";
+    //run_test(startpos,es,defaultEdgeLength,cx,cy,CG,false,f,"cg");
+    //run_test(startpos,es,defaultEdgeLength,cx,cy,IP,false,f,"ip");
+    //run_test(startpos,es,defaultEdgeLength,cx,cy,UGP,false,f,"ugp");
+    //run_test(startpos,es,defaultEdgeLength,cx,cy,SGP,false,f,"sgp");
+    //run_test(startpos,es,defaultEdgeLength,cx,cy,IP,true,f,"cip");
+    //run_test(startpos,es,defaultEdgeLength,cx,cy,UGP,true,f,"cugp");
+    run_test(startpos,es,defaultEdgeLength,cx,cy,SGP,true,f,"csgp");
+}
+int main() {
+    for(unsigned i=1;i<2;i++) {
+        scale_free(i*50);
+    }
+    return 0;
+}
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=4:softtabstop=4:textwidth=99 :