rand-fst.h
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#ifndef FST_TEST_RAND_FST_H_
#define FST_TEST_RAND_FST_H_
#include <fst/log.h>
#include <fst/mutable-fst.h>
#include <fst/verify.h>
namespace fst {
// Generates a random FST.
template <class Arc, class WeightGenerator>
void RandFst(const int num_random_states, const int num_random_arcs,
const int num_random_labels, const float acyclic_prob,
WeightGenerator *weight_generator, MutableFst<Arc> *fst) {
typedef typename Arc::Label Label;
typedef typename Arc::StateId StateId;
typedef typename Arc::Weight Weight;
// Determines direction of the arcs wrt state numbering. This way we
// can force acyclicity when desired.
enum ArcDirection {
ANY_DIRECTION = 0,
FORWARD_DIRECTION = 1,
REVERSE_DIRECTION = 2,
NUM_DIRECTIONS = 3
};
ArcDirection arc_direction = ANY_DIRECTION;
if (rand() / (RAND_MAX + 1.0) < acyclic_prob)
arc_direction = rand() % 2 ? FORWARD_DIRECTION : REVERSE_DIRECTION;
fst->DeleteStates();
StateId ns = rand() % num_random_states;
if (ns == 0) return;
for (StateId s = 0; s < ns; ++s) fst->AddState();
StateId start = rand() % ns;
fst->SetStart(start);
size_t na = rand() % num_random_arcs;
for (size_t n = 0; n < na; ++n) {
StateId s = rand() % ns;
Arc arc;
arc.ilabel = rand() % num_random_labels;
arc.olabel = rand() % num_random_labels;
arc.weight = (*weight_generator)();
arc.nextstate = rand() % ns;
if ((arc_direction == FORWARD_DIRECTION ||
arc_direction == REVERSE_DIRECTION) &&
s == arc.nextstate) {
continue; // skips self-loops
}
if ((arc_direction == FORWARD_DIRECTION && s > arc.nextstate) ||
(arc_direction == REVERSE_DIRECTION && s < arc.nextstate)) {
StateId t = s; // reverses arcs
s = arc.nextstate;
arc.nextstate = t;
}
fst->AddArc(s, arc);
}
StateId nf = rand() % (ns + 1);
for (StateId n = 0; n < nf; ++n) {
StateId s = rand() % ns;
Weight final = (*weight_generator)();
fst->SetFinal(s, final);
}
VLOG(1) << "Check FST for sanity (including property bits).";
CHECK(Verify(*fst));
// Get/compute all properties.
uint64 props = fst->Properties(kFstProperties, true);
// Select random set of properties to be unknown.
uint64 mask = 0;
for (int n = 0; n < 8; ++n) {
mask |= rand() & 0xff;
mask <<= 8;
}
mask &= ~kTrinaryProperties;
fst->SetProperties(props & ~mask, mask);
}
} // namespace fst
#endif // FST_TEST_RAND_FST_H_