def ctc_ref(acts, lbls, utt_lens, lbl_lens):
"""
CTC reference implementation
"""
warp_ctc = CTC(on_device='cpu')
max_t, bsz, nout = acts.shape
grads = np.zeros_like(acts)
costs = np.zeros(bsz, dtype=acts.dtype)
utt_lens = (utt_lens * max_t / 100).astype(np.int32)
warp_ctc.bind_to_cpu(acts,
lbls,
utt_lens,
lbl_lens,
grads,
costs,
n_threads=8)
return costs, grads
def ctc_cpu(acts, lbls, utt_lens, lbl_lens, grads, costs, n_threads=8):
global warp_ctc
if warp_ctc is None:
warp_ctc = CTC(on_device='cpu')
costs.fill(0.)
grads.fill(0.)
max_t, bsz, nout = acts.shape
utt_lens = (utt_lens * max_t / 100).astype(np.int32)
lbls = lbls.astype(np.int32)
lbl_lens = lbl_lens.astype(np.int32)
warp_ctc.bind_to_cpu(acts,
lbls,
utt_lens,
lbl_lens,
grads,
costs,
n_threads=n_threads)