/// <summary>
/// Copy one FST to another.
/// </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(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()");
}
for (int j = 0; j < inputs.Length(); j++)
{
dst.AddTransition(i, targets.At1d(j), outputs.At1d(j), costs.At1d(j), inputs.At1d(j));
}
}
}
/// <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]);
}
}
}
protected static void read_header_and_symbols(IGenericFst fst, BinaryReader reader)
{
if (read_int32_LE(reader) != OPENFST_MAGIC)
{
throw new Exception("invalid magic number");
}
read_magic_string(reader, "vector");
read_magic_string(reader, "standard");
int version = read_int32_LE(reader);
if (version < MIN_VERSION)
{
throw new Exception("file has too old version");
}
int flags = read_int32_LE(reader);
read_int64_LE(reader); // properties
Int64 start = read_int64_LE(reader);
Int64 nstates = read_int64_LE(reader);
if (nstates < 0)
{
return; // to prevent creating 2^31 nodes in case of sudden EOF
}
fst.Clear();
for (int i = 0; i < nstates; i++)
{
fst.NewState();
}
fst.SetStart((int)start);
read_int64_LE(reader); // narcs
if ((flags & FLAG_HAS_ISYMBOLS) > 0)
{
skip_symbol_table(reader);
}
if ((flags & FLAG_HAS_OSYMBOLS) > 0)
{
skip_symbol_table(reader);
}
}
/// <summary>
/// Reverse the FST's arcs, adding a new start vertex (former accept).
/// </summary>
public static void fst_copy_reverse(IGenericFst dst, IGenericFst src, bool no_accept = false)
{
dst.Clear();
int n = src.nStates();
for (int i = 0; i <= n; i++)
{
dst.NewState();
}
if (!no_accept)
{
dst.SetAccept(src.GetStart());
}
dst.SetStart(n);
for (int i = 0; i < n; i++)
{
dst.AddTransition(n, i, 0, src.GetAcceptCost(i), 0);
Intarray targets = new Intarray(), outputs = new Intarray(), inputs = new Intarray();
Floatarray costs = new Floatarray();
src.Arcs(inputs, targets, outputs, costs, i);
if (inputs.Length() != targets.Length())
{
throw new Exception("ASSERT: inputs.length() == targets.length()");
}
if (inputs.Length() != outputs.Length())
{
throw new Exception("ASSERT: inputs.length() == outputs.length()");
}
if (inputs.Length() != costs.Length())
{
throw new Exception("ASSERT: inputs.length() == costs.length()");
}
for (int j = 0; j < inputs.Length(); j++)
{
dst.AddTransition(targets.At1d(j), i, outputs.At1d(j), costs.At1d(j), inputs.At1d(j));
}
}
}
/// <summary>
/// Output the segmentation into a segmentation graph.
/// Construct a state for each of the segments, then
/// add transitions between states (segments)
/// from min(segments[i]) to max(segments[i])+1.
/// </summary>
public override void GetLattice(IGenericFst fst)
{
fst.Clear();
int final = NarrayUtil.Max(labels) + 1;
Intarray states = new Intarray(final + 1);
states.Fill(-1);
for (int i = 1; i < states.Length(); i++)
{
states[i] = fst.NewState();
}
fst.SetStart(states[1]);
fst.SetAccept(states[final]);
for (int i = 0; i < boxes.Length(); i++)
{
int start = NarrayUtil.Min(segments.At1d(i));
int end = NarrayUtil.Max(segments.At1d(i));
int id = (start << 16) + end;
if (segments.At1d(i).Length() == 0)
{
id = 0;
}
float yes = spaces[i, 0];
float no = spaces[i, 1];
// if no space is set, assume no space is present
if (yes == float.PositiveInfinity && no == float.PositiveInfinity)
{
no = 0.0f;
}
for (int j = 0; j < class_costs[i].Length(); j++)
{
float cost = class_costs[i][j];
string str = class_outputs[i][j];
int n = str.Length;
int last = start;
for (int k = 0; k < n; k++)
{
int c = (int)str[k];
if (k < n - 1)
{
// add intermediate states/transitions for all but the last character
states.Push(fst.NewState());
fst.AddTransition(states[last], states.Last(), c, 0.0f, 0);
last = states.Length() - 1;
}
else
{
// for the last character, handle the spaces as well
if (no < 1000.0f)
{
// add the last character as a direct transition with no space
fst.AddTransition(states[last], states[end + 1], c, cost + no, id);
}
if (yes < 1000.0f)
{
// insert another state to handle spaces
states.Push(fst.NewState());
int space_state = states.Last();
fst.AddTransition(states[start], space_state, c, cost, id);
fst.AddTransition(space_state, states[end + 1], (int)' ', yes, 0);
}
}
} // for k
} // for j
} // for i
}
