def test_dwt_idwt_inverse():
"""dwt/idwt should invert each other (to machine precision)"""
from electrolib.filters.dwtfile import WaveletFilter as W
x = np.sin(np.arange(0,10,0.1))
w = W.wavelet('db2')
zi = W.zero_state(w)
cA, cD, zf = W.dwt(x, w, zi)
x_rec = W.idwt(cA, cD, w)
assert np.allclose(x, x_rec)
def test_dwt_blocks():
"""dwt block filtering should be nearly equal to dwt1 in one go"""
# Basic setup
from electrolib.filters.dwtfile import WaveletFilter as W
x = np.sin(np.arange(0,10,0.1))
w = W.wavelet('db2')
zi = W.zero_state(w)
overlap = len(zi[0])
# Prepare for loop
nstep = 10
cA = np.zeros(len(x)/2)
cD = np.zeros_like(cA)
state = zi
for n in range(0, len(x), nstep):
cAn, cDn, state = W.dwt(x[n:n+nstep], w, state)
cA[n/2:(n+nstep)/2] = cAn[:-overlap]
cD[n/2:(n+nstep)/2] = cDn[:-overlap]
# Do in one go
cA1, cD1, zf = W.dwt(x, w, zi)
cA1 = cA1[:-overlap]
cD1 = cD1[:-overlap]
assert np.allclose(cA1, cA)
assert np.allclose(cD1, cD)