--- /dev/null
+typedef struct{
+ int set1;
+ int set2;
+ float distance;
+ float distance2;
+ } Union;
+
+extern Union *wards_cluster(float **clmat);
+extern Union *neighbour_joining(float **clmat);
+extern void printf_phylogeny(Union *tree, char *type);
+
+
+/* Auxiliary information in a Union tree:
+ tree[0].set1 contains the number of elements of tree, i.e.,
+ tree[tree[0].set1-1]] is the last one !!
+*/