/// <summary>
/// Copy one FST to another, preserving only lowest-cost arcs.
/// This is useful for visualization.
/// </summary>
/// <param name="dst">The destination. Will be cleared before copying.</param>
/// <param name="src">The FST to copy.</param>
public static void fst_copy_best_arcs_only(IGenericFst dst, IGenericFst src)
{
dst.Clear();
int n = src.nStates();
for (int i = 0; i < n; i++)
{
dst.NewState();
}
dst.SetStart(src.GetStart());
for (int i = 0; i < n; i++)
{
dst.SetAccept(i, src.GetAcceptCost(i));
Intarray targets = new Intarray(), outputs = new Intarray(), inputs = new Intarray();
Floatarray costs = new Floatarray();
src.Arcs(inputs, targets, outputs, costs, i);
int inlen = inputs.Length();
if (inlen != targets.Length())
{
throw new Exception("ASSERT: inputs.length() == targets.length()");
}
if (inlen != outputs.Length())
{
throw new Exception("ASSERT: inputs.length() == outputs.length()");
}
if (inlen != costs.Length())
{
throw new Exception("ASSERT: inputs.length() == costs.length()");
}
Dictionary <int, int> hash = new Dictionary <int, int>();
for (int j = 0; j < n; j++)
{
int t = targets[j];
int best_so_far = -1;
if (hash.ContainsKey(t))
{
best_so_far = hash[t];
}
if (best_so_far == -1 || costs[j] < costs[best_so_far])
{
hash[t] = j;
}
}
Intarray keys = new Intarray();
//hash.keys(keys);
keys.Clear();
foreach (int key in hash.Keys)
{
keys.Push(key);
}
for (int k = 0; k < keys.Length(); k++)
{
int j = hash[keys[k]];
dst.AddTransition(i, targets[j], outputs[j], costs[j], inputs[j]);
}
}
}
