in whisper/timing.py [0:0]
def dtw_cpu(x: np.ndarray):
N, M = x.shape
cost = np.ones((N + 1, M + 1), dtype=np.float32) * np.inf
trace = -np.ones((N + 1, M + 1), dtype=np.float32)
cost[0, 0] = 0
for j in range(1, M + 1):
for i in range(1, N + 1):
c0 = cost[i - 1, j - 1]
c1 = cost[i - 1, j]
c2 = cost[i, j - 1]
if c0 < c1 and c0 < c2:
c, t = c0, 0
elif c1 < c0 and c1 < c2:
c, t = c1, 1
else:
c, t = c2, 2
cost[i, j] = x[i - 1, j - 1] + c
trace[i, j] = t
return backtrace(trace)