Hi,
How ca I Implement the algorithm for calculating the transitive closure given a set of functional dependencies? I have sent the detail of this algorithm in a ZIP file.
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Farhan ShariffPosted Jun 2, 2016, 4:35 PM
/*
1 let dist be a |V| × |V| array of minimum distances initialized to ∞ (infinity)
2 for each vertex v
3 dist[v][v] ← 0 4 for each edge (u,v)
5 dist[u][v] ← w(u,v) // the weight of the edge (u,v)
6 for k from 1 to |V|
7 for i from 1 to |V|
8 for j from 1 to |V|
9 if dist[i][j] > dist[i][k] + dist[k][j]
10 dist[i][j] ← dist[i][k] + dist[k][j]
11 end if
*/
#include
// Number of vertices in the graph
#define V 4
// A function to print the solution matrix
void printSolution(int reach[][V]);
void transitiveClosure(int graph[][V])
{
/* reach[][] will be the output matrix that will finally have the
shortest distances between every pair of vertices */
int reach[V][V], i, j, k;
/* Initialize the solution matrix same as input graph matrix. Or
we can say the initial values of shortest distances are based
on shortest paths considering no intermediate vertex. */
for (i = 0; i < V; i++)
for (j = 0; j < V; j++)
reach[i][j] = graph[i][j];
/* Add all vertices one by one to the set of intermediate vertices.
---> Before start of a iteration, we have reachability values for
all pairs of vertices such that the reachability values
consider only the vertices in set {0, 1, 2, .. k-1} as
intermediate vertices.
----> After the end of a iteration, vertex no. k is added to the
set of intermediate vertices and the set becomes {0, 1, .. k} */
for (k = 0; k < V; k++)
{
// Pick all vertices as source one by one
for (i = 0; i < V; i++)
{
// Pick all vertices as destination for the
// above picked source
for (j = 0; j < V; j++)
{
// If vertex k is on a path from i to j,
// then make sure that the value of reach[i][j] is 1
reach[i][j] = reach[i][j] || (reach[i][k] && reach[k][j]);
}
}
}
// Print the shortest distance matrix
printSolution(reach);
}
/* A utility function to print solution */
void printSolution(int reach[][V])
{
printf ("Following matrix is transitive closure of the given graph\n");
for (int i = 0; i < V; i++)
{
for (int j = 0; j < V; j++)
printf ("%d ", reach[i][j]);
printf("\n");
}
}
int main()
{
int graph[V][V] = { {1, 1, 0, 1},
{0, 1, 1, 0},
{0, 0, 1, 1},
{0, 0, 0, 1}
};
// Print the solution
transitiveClosure(graph);
return 0;
}
Ranjan DailataPosted Apr 4, 2016, 8:52 AM